Magnesium and its alloys have gained relevance for their light-weight combined with a high value of strength-to-weight ratio,which makes them useful in fields such as aerospace,automotive as well as biomedical enginee...Magnesium and its alloys have gained relevance for their light-weight combined with a high value of strength-to-weight ratio,which makes them useful in fields such as aerospace,automotive as well as biomedical engineering.Unfortunately,the poor corrosion resistance of Mg-alloys limits their wide acceptance.Advanced composite coatings which are self-healing,superhydrophobic anti corrosive,and wear resistant are new synthetic materials for abating these challenges.The superimposed superhydrophobic surfaces help in minimizing their water contact,thus slowing down the electrochemical reactions on the surface of the alloys,while their self-healing characteristics autonomously aid in the repair of any induced micro-crack,defect or damage towards ensuring the metal's long-term protection.In addition,the integration of wear-resistant materials further improves the durability of coatings under mechanical stress.The most recent research efforts have been directed towards the preparation of multifunctional composites,with an emphasis on nanomaterials,functional polymers,and state-of-the-art fabrication techniques in order to take advantage of their synergistic effects.Some of the methods that have so far exhibited promising potentials in fabricating these materials include the sol-gel method,layer-by-layer assembly,and plasma treatments.However,most of the fabricated products are still faced with significant challenges ranging from long-term stability to homogeneous adhesion of the coatings and their scalability for industrial applications.This review discusses the recent progress and the relationship between corrosion inhibition and self-healing efficiencies of wear resistant polymer nanocomposite coatings.Some challenges related to optimizing coating performance were also discussed.In addition,future directions ranging from the consideration of bioinspired designs,novel hybrid nanocomposite materials,and environmentally sustainable solutions integrated with smart protective coatings were also proposed as new wave technologies that can potentially revolutionize the corrosion protection offered by Mg alloys while opening up prospects for improved performance and sustainability.展开更多
Cu–Ni and Cu–Co–Ni superhydrophobic films were constructed on the surface of B10 copper–nickel alloy welded joints using a two-step process of electrodeposition and stearic acid modification.The chemical compositi...Cu–Ni and Cu–Co–Ni superhydrophobic films were constructed on the surface of B10 copper–nickel alloy welded joints using a two-step process of electrodeposition and stearic acid modification.The chemical composition of the film surface was determined using surface characterization techniques.The corrosion resistance of the films was characterized using electrochemical impedance spectroscopy,potentiodynamic polarization,and scanning Kelvin probe microscopy at multiple scales.The thermal stability,mechanical stability,and self-cleaning properties of the films were also characterized.It was determined that the Cu–Co–Ni superhydrophobic film exhibited the best performance,with a static water contact angle of 159.3°,a roll-off angle of 2.3°,a charge transfer resistance 3300 times higher than the substrate,a self-corrosion current density nearly three orders of magnitude lower,and a surface Kelvin potential increase of 420 mV.The film demonstrated good thermal stability,excellent mechanical stability,and outstanding self-cleaning properties.Combining with previous studies,it was found that Co elements in the film contribute to the formation of a uniform and dense film,Ni elements enhance the adhesion and corrosion resistance between the films,and the combination of Co and Ni elements promotes uniform surface potential and further improves the corrosion resistance and interfilm adhesion of the films.展开更多
Wrought and laser powder bed fusion(LPBF)Ti−6Al−4V(Ti-6-4)specimens were comparatively evaluated,with the objective to determine LPBF Ti−6Al−4V’s suitability for biomedical applications.Testing included nanoindentati...Wrought and laser powder bed fusion(LPBF)Ti−6Al−4V(Ti-6-4)specimens were comparatively evaluated,with the objective to determine LPBF Ti−6Al−4V’s suitability for biomedical applications.Testing included nanoindentation,cyclic polarization in simulated body fluid(SBF,37°C),and dry and SBF“ball-on-plate”sliding.Wrought Ti-6-4 exhibited a lamellarα+βmicrostructure,whereas LPBF Ti-6-4 displayed a fine-grainedα′-martensite microstructure.LPBF Ti-6-4 demonstrated~3%higher indentation modulus and~32%higher hardness,while wrought Ti-6-4 showed~8%higher plasticity.Both alloys exhibited low corrosion rates(10−5 mA/cm^(2)order)and true passivity(10−4 mA/cm^(2)order).No localized corrosion was observed in either two alloys,except for occasional metastable pitting in the LPBF alloy.However,LPBF Ti-6-4 presented higher corrosion rate and passive current,ascribed to its martensitic structure.During dry sliding,LPBF Ti-6-4 exhibited~14%lower volume loss compared to wrought Ti-6-4.Sliding in SBF increased volume losses for both alloys,with wear resistances nearly equalized,as the advantage of LPBF Ti-6-4 decreased due to more intense wear-accelerated corrosion induced by the stressed martensite.Overall,the results demonstrate the suitability of LPBF Ti-6-4 for biomedical uses.展开更多
BACKGROUND Corrosive ingestion remains an important global pathology with high morbidity and mortality.Data on the acute management of adult corrosive injuries from sub-Saharan Africa is scarce,with international inve...BACKGROUND Corrosive ingestion remains an important global pathology with high morbidity and mortality.Data on the acute management of adult corrosive injuries from sub-Saharan Africa is scarce,with international investigative algorithms,relying heavily on computed tomography(CT),having limited availability in this setting.AIM To investigate the corrosive injury spectrum in a low-resource setting and the applicability of parameters for predicting full-thickness(FT)necrosis and mortality.METHODS A retrospective analysis of a prospective corrosive injury registry(March 1,2017–October 31,2023)was performed to include all adult patients with acute corrosive ingestion managed at a single,academic referral centre in Cape Town,South Africa.Patient demographics,corrosive ingestion details,initial investigations,management,and short-term outcomes were described using descriptive statistics while multivariate analysis with receiver operator characteristic area under the curve graphs(ROC AUC)were used to identify factors predictive of FT necrosis and 30-day mortality.RESULTS One-hundred patients were included,with a mean age of 32 years(SD:11.2 years)and a male predominance(65.0%).The majority(73.0%)were intentional suicide attempts.Endoscopy on admission was the most frequent initial investigation performed(95 patients),while only 17 were assessed with CT.Seventeen patients had full thickness necrosis at surgery,of which eleven underwent emergency resection and six were palliated.Thirty-day morbidity and mortality were 27.0%and 14.0%,respectively.Patients with full thickness necrosis and those with an established perforation had a 30-day mortality of 58.8%and 91.0%,respectively.Full thickness necrosis was associated with a cumulative 2-year survival of only 17.6%.Multivariate analyses with ROC AUC showed admission endoscopy findings,CT findings,and blood gas findings(pH,base excess,lactate),to all have significant predictive value for full thickness necrosis,with endoscopy proving to have the best predictive value(AUC 0.850).CT and endoscopy findings were the only factors predictive of early mortality,with CT performing better than endoscopy(AUC 0.798 vs 0.759).CONCLUSION Intentional corrosive injuries result in devastating morbidity and mortality.Locally,early endoscopy remains the mainstay of severity assessment,but referral for CT imaging should be considered especially when blood gas findings are abnormal.展开更多
The self-assembly of hybrid inorganic-organic materials on stationary platforms plays a critical role in improving their structural stability and wide usability.In this work,a novel two-step hydrothermal approach is p...The self-assembly of hybrid inorganic-organic materials on stationary platforms plays a critical role in improving their structural stability and wide usability.In this work,a novel two-step hydrothermal approach is proposed for synthesizing stable and advanced hybrid coatings on metal-oxide platforms through the surface modification of layered double hydroxide(LDH)films using novel metal-organic frameworks(MOFs).Initially,Mg-Al LDH nanocontainers,grown on a magnesium oxide layer produced through plasma electrolytic oxidation(PEO)of AZ31 Mg alloy substrate,were intercalated with cobalt via an oxidation route,providing the metallic coordination center for the MOF formation.In the subsequent step,a pioneering technique is introduced,utilizing tryptophan as the organic linker for the first time at a pH of 10.The self-assembly of cobalt-tryptophan complex,driven by the strong bonding between electrophilic sites of monomers and nucleophilic sites,facilitated the formation of a MOF network having a cloud-like structure on the surface of MgAl LDH's film.The resulting MOF-LDH encapsulation containers demonstrate exceptional electrochemical stability when exposed to a 3.5 wt.%NaCl solution,surpassing the performance of PEO and pure LDH coatings.This enhanced stability is attributed to the development of a dense top layer and a stable composition within the self-assembled MOF,effectively sealing flaws and preventing the infiltration of corrosive ions into the underlying metallic substrate.The formation mechanism of MOFs on LDH galleries is investigated using density functional theory calculations.展开更多
Owing to the significant potential of alkalin seawater electrolysis for converting surplus power into eco friendly hydrogen fuel,we developed bifunctional elec trodes that integrate low-crystalline NiFe LDHs and amorp...Owing to the significant potential of alkalin seawater electrolysis for converting surplus power into eco friendly hydrogen fuel,we developed bifunctional elec trodes that integrate low-crystalline NiFe LDHs and amorphous NiFe alloy on a Ni foam(NF)substrate to enhance this process.Driven by the battery-like charac teristics of NiFe LDHs,an anti-corrosive and active oute layer of NiFe^(vac)OOH continuously forms over time in th hybrid on the anode for the oxygen evolution reaction(OER),effectively mitigating powder shedding caused by corrosion induced by multiple anions in seawater.Mean while,the strong bond between the hybrid and the NF substrate maintains intact hybrid coatings to ensure a rel atively high overall conductivity of the electrodes,signif icantly reducing the negative effects of structura degradation during the OER and hydrogen evolution reaction(HER),as well as the accumulation of contami nants on the electrode surfaces.In long-term tests,thes bifunctionalhybridelectrodesmaintained stable performance,even at a high current density o500 mA·cm^(-2).The cell voltage increased by only 88 m V over 1000 h to 1.970 V during saline electrolysis and by103 mV over 500 h to 2.062 V during seawater electroly sis.Hence,this study provides valuable insights into efficient and stable seawater electrolysis using NiFe LDHs–NiFe alloy hybrids.展开更多
Coatings or surface modification are a very attractive strategy for protecting metal against corrosion in construction,chemical industries,automotive,ships and aerospace applications.The original idea to mitigate the ...Coatings or surface modification are a very attractive strategy for protecting metal against corrosion in construction,chemical industries,automotive,ships and aerospace applications.The original idea to mitigate the corrosion process aims to prepare a coating or pretreatment layer to isolate the corrosive environment and the traditional field of metal materials to provide physical barrier.Nowadays,with the development of the novel coating composition,machine learning(ML)techniques prediction,which was endowed unprecedented functionality,such as self healing,self-reporting,self-lubrication and anti-fouling properties,is driving the field of application also extend to microelectronics and energy(anode material,metal batteries).展开更多
Advanced hybrid materials with unique properties are essential for addressing the demands of increasingly complex applications.Despite their importance,the self-assembly of layered double hydroxides(LDH)with metallic ...Advanced hybrid materials with unique properties are essential for addressing the demands of increasingly complex applications.Despite their importance,the self-assembly of layered double hydroxides(LDH)with metallic oxide nanoparticles and dicarboxylic acids is constrained by a limited understanding of the formation mechanisms and difficulties in evaluating their anticorrosive performance.In this study,we developed a novel anticorrosive system by intercalating CeNiLDH with a complex of vanadium pentoxide(V2O5)nanoparticles and(2E)-but-2-enedioic acid((2E)-BDA)on a MgO layer created through plasma-electrolysis of AZ31 Mg alloy.This system was compared with LDH films intercalated with either V2O5 or(2E)-BDA alone.The intercalation of LDH with V_(2)O_(5)and(2E)-BDA resulted in a flower-like structure,while modification with their complex led to a more compact,cloud-like formation.These cloud-like structures,driven by enhanced absorption and robust hydrogen bonding throughout the hierarchical network,effectively suppress corrosion by delaying the movement of corrosive anions.This was reflected in a polarization resistance of 1.51×10^(10)Ω·cm^(2),which is approximately two orders of magnitude times higher than the resistance of the unmodified LDH film(3.41×10^(8)Ω·cm^(2)).Additionally,the corrosion current density(icorr)of the VOBDA sample showed a decrease by four orders of magnitude compared to the unmodified LDH sample,emphasizing the superior anticorrosive performance of this hybrid coating.Density functional theory(DFT)was used to elucidate the bonding and formation mechanisms between LDH and the inorganic-organic complex.展开更多
In this paper, through the data treatment of correlation coefficients and the clustering technique of pattern recognition, both the matrix of correlation coefficients and the pedigree of factor clusters show that some...In this paper, through the data treatment of correlation coefficients and the clustering technique of pattern recognition, both the matrix of correlation coefficients and the pedigree of factor clusters show that some factors affecting soil corrosivity are interrelated closely, and some independent relatively. The data analytical method used in this paper has certain assistance to the selection of major soil factors during the prediction and evaluation of soil corrosivity.展开更多
BACKGROUND Aorto-oesophageal fistula(AOF)are uncommon and exceedingly rare after corrosive ingestion.The authors report a case of AOF after corrosive ingestion that survived.A comprehensive literature review was perfo...BACKGROUND Aorto-oesophageal fistula(AOF)are uncommon and exceedingly rare after corrosive ingestion.The authors report a case of AOF after corrosive ingestion that survived.A comprehensive literature review was performed to identify all cases of AOF after corrosive ingestion to determine the incidence of this condition,how it is best managed and what the outcomes are.CASE SUMMARY A previously healthy 30-year-old male,presented with a corrosive oesophageal injury after drain cleaner ingestion.He did not require acute surgical resection,but developed long-segment oesophageal stricturing,which was initially managed with cautious dilatation and later stenting.An AOF was suspected at endoscopy performed two months after the ingestion,when the patient represented with massive upper gastrointestinal bleeding.The fistula was confirmed on computerised tomographic angiography.The initial bleeding at endoscopy was temporised by oesophageal stenting;a second stent was placed when bleeding recurred later the same day.The stenting successfully achieved temporary bleeding control,but resulted in sudden respiratory distress,which was found to be due to left main bronchus compression caused by the overlapping oesophageal stents.Definitive bleeding control was achieved by endovascular aortic stent-grafting.A retrosternal gastroplasty was subsequently performed to achieve gastrointestinal diversion to reduce the risk of stent-graft sepsis.He was subsequently successfully discharged and remains well one year post injury.CONCLUSION AOF after corrosive ingestion is exceedingly rare,with a very high mortality.Most occur weeks to months after the initial corrosive ingestion.Conservative management is ill-advised.展开更多
Galvanic corrosion of tri-metallic couples is more complicated than that of bi-metallic couples. In this study, the effect of the pH of corrosive media on the galvanic corrosion of 2024 A1 alloy/Q235 mild steel/304 st...Galvanic corrosion of tri-metallic couples is more complicated than that of bi-metallic couples. In this study, the effect of the pH of corrosive media on the galvanic corrosion of 2024 A1 alloy/Q235 mild steel/304 stainless steel tri-metallic couples was investigated using potentiodynamic polarization, scanning electron microscopy, scanning vibrating electrode technique and a multi-channel galvanic corrosion meter. The results show that 2024 always acts as the only anode in 3.5 wt% NaCl at pH 5.56,9.72 and 12.0, while both Q235 and 2024 act as anodes at pH 2.39 in the initial stage and then the role of Q235 changes at longer coupling time, which can be attributed to the effect of pH on the surface film of 2024. It is also found that the galvanic current density of a tri-metallic couple is the superposition of two bi-metallic couples when cathodic reactions are controlled by the diffusion of oxygen, otherwise it is smaller than that of the sum of two bi-metallic couples. The localized corrosion instead of uniform corrosion of anodic metal is accelerated by galvanic corrosion.展开更多
Tribological properties of impregnated graphite are greatly influenced by preparation technology and working conditions and it’s highly susceptible to corrosion environmental impacts,but the experimental research abo...Tribological properties of impregnated graphite are greatly influenced by preparation technology and working conditions and it’s highly susceptible to corrosion environmental impacts,but the experimental research about it are few.In this paper,three kinds of impregnated graphite samples are prepared with different degree of graphitization,the tribological properties of these samples in the dry friction environment and in a corrosive environment are analyzed and contrasted.The tribo-test results show that the friction coefficient of samples is reduced and the amount of wear of samples increase when the graphitization degree of samples increases in dry friction condition.While in a corrosive environment（samples are soaked N2O4）,the friction coefficient and amount of wear are changed little if the graphitization degree of samples are low.If the degree of graphitization increase,the friction coefficient and amount of wear of samples increase too,the amount of wear is 2 to 3 times as the samples tested in the non-corrosive environment under pv value of 30MPa？m/s.The impregnated graphite,which friction coefficient is stable and graphitization degree is in mid level,such#2,is more appropriate to have a work in the corrosion conditions.In this paper,preparation and tribological properties especially in corrosive environment of the impregnated graphite is studied,the research conclusion can provide an experimental and theoretical basis for the selection and process improvement of graphite materials,and also provide some important design parameters for contact seal works in a corrosive environment.展开更多
Anaerobic, aerobic, and facultative bacteria are all present in corrosive environments. However, as previous studies to address corrosion in the marine environment have largely focused on anaerobic bacteria, limited a...Anaerobic, aerobic, and facultative bacteria are all present in corrosive environments. However, as previous studies to address corrosion in the marine environment have largely focused on anaerobic bacteria, limited attention has been paid to the composition and function of aerobic and facultative bacteria in this process. For analysis in this study, ten samples were collected from rust layers on steel plates that had been immersed in seawater for diff erent periods (i.e., six months and eight years) at Sanya and Xiamen, China. The cultivable aerobic bacterial community structure as well as the number of sulfate-reducing bacteria (SRB) were analyzed in both cases, while the proportion of facultative SRB among the isolated aerobic bacteria in each sample was also evaluated using a novel approach. Bacterial abundance results show that the proportions are related to sea location and immersion time;abundances of culturable aerobic bacteria (CAB) and SRB from Sanya were greater in most corrosion samples than those from Xiamen, and abundances of both bacterial groups were greater in samples immersed for six months than for eight years. A total of 213 isolates were obtained from all samples in terms of CAB community composition, and a phylogenetic analysis revealed that the taxa comprised four phyla and 31 genera. Bacterial species composition is related to marine location;the results show that Firmicutes and Proteobacteria were the dominant phyla, accounting for 98.13% of the total, while Bacillus and Vibrio were the dominant genera, accounting for 53.06% of the total. An additional sixfacultative SRB strains were also screened from the isolates obtained and were found to encompass the genus Vibrio (four strains), Staphylococcus (one strain), and Photobacterium (one strain). It is noteworthy that mentions of Photobacterium species have so far been absent from the literature, both in terms of its membership of the SRB group and its relationship to corrosion.展开更多
This paper deals with a correction method for corrosive crack width caused by non-uniform corrosion. Considering the corrosion cracking characteristics of a reinforced concrete structure, a correction model of corrosi...This paper deals with a correction method for corrosive crack width caused by non-uniform corrosion. Considering the corrosion cracking characteristics of a reinforced concrete structure, a correction model of corrosive crack width involving the mutual impacts between adjacent measuring points is established. The calculation model for steel bar corrosion rate for single point is obtained through quantitative analysis and accelerated corrosion tests on more than 70 reinforced cubic members. Two methods are suggested by combining two models, the correction and the corrosion calculation ones. Electrolyte accelerated cor- rosion tests on seven beams are carried out to verify these methods. The experimental results show that the ratio between the maximum corrosion rate by the indirect method and the measured average value ranges from 1.4 to 2.4, and the indirect method is shown to be an effective method for calculating the maximum corrosion rate.展开更多
Expandable rock bolts are widely used in hard rock mines as an efficient ground control product.However, capacity and service life can be significantly reduced if the metallic body is subjected to corrosion.In some ha...Expandable rock bolts are widely used in hard rock mines as an efficient ground control product.However, capacity and service life can be significantly reduced if the metallic body is subjected to corrosion.In some hard rock mines in the U.S., highly corrosive ground conditions exist, and it has been reported that inflatable rock bolts have corroded within a few months after installation.To provide mining industry a cost-effective inflatable bolt and combat the corrosion issues, Jennmar Corporation, Inc.,and its subsidiary Keystone Mining Services, LLC(KMS), analyzed corroded bolt samples, identified root causes, evaluated properties of various coating materials, and developed a new inflatable rock bolt,Python M3^(TM), that is protected with an innovative PyFlexU2^(TM)coating.The new generation Python M3^(TM) features improved steel chemistry for reliable performance, modified profile for better inflation, and surface preparation and coating application.The PyFlexU2^(TM)is impervious to liquid and air, durable, and UV resistant.With a flexible, adhesive, and highly corrosion-resistant undercoating, and a very hard sacrificial surface coating, the PyFlexU2^(TM)coating system provides the Python M3^(TM)superior protection against chemical corrosion and physical scratch damage.The under-coating has exceptional flexibility and adhesion to prevent coating micro-cracks or fractures after bolt inflation and possesses excellent corrosion resistance to acids(pH < 3), alkalis(p H > 11), fuels, and salt solvents.The corrosion and scratch resistant PyFlexU2^(TM)coating offers very effective bolt protection for extra longevity in highly corrosive environments.The Python M3^(TM)coated with PyFlexU2^(TM)has been tested in the most challenging conditions,including laboratory corrosion tests in extreme acidic and basic solvents, rock slurry, and borehole scratch insertion tests.With demonstrated corrosion and scratch resistance, the product has been greatly welcomed by hard rock mines in the West and is currently installed in large scale.This paper identifies the root causes of the bolt corrosion, discusses the analysis process, and details laboratory and underground tests carried out on the Python M3^(TM)coated with PyFlexU2^(TM).The Python M3^(TM)and PyFlexU2^(TM) are subjects covered by pending U.S.Patent Applications assigned to FCI Holdings Delaware, LLC.展开更多
The corrosion, corrosive wear and dry sliding wear of nanocomposites, are extremely complicated and involve various chemical, physical anbd mechanical factors. The aim of this work is to investigate the effects of nan...The corrosion, corrosive wear and dry sliding wear of nanocomposites, are extremely complicated and involve various chemical, physical anbd mechanical factors. The aim of this work is to investigate the effects of nanosized SiC content on the hardness, dry sliding wear, corrosion and corrosive wear of Al/SiC nanocomposites synthesized by mechanical milling cold pressing and hot extrusion. The corrosion resistance of these composites in 3%NaCl solution was investigated by electrochemical polarization testing and their dry sliding as well as corrosive wear resistance in the same solution was evaluated using a pin-on-disc tester. The microstructures of the samples and their worn surfaces were examined using scanning electron microscopy. It was shown that the dry sliding wear and corrosion resistance of these nanocomposites were improved with the increase of SiC content. It was concluded that due to the lubrication effect of the solution, both the friction coefficient and frictional heat that might soften the material were reduced. In addition, the improved strength of the nanocomposites combined with their better corrosion resistance contributed to their increased corrosive wear resistance, compared with the base alloy. The prominent wear mechanism in the unreinforced alloy was adhesive wear, in the Al/SiC nanocomposites, the wear mechanism changed to abrasive.展开更多
TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. In this paper, it was demonstrated that by addition of yttrium, hardness properties and resistance to...TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. In this paper, it was demonstrated that by addition of yttrium, hardness properties and resistance to wear and corrosive wear of TiNi alloy were improved. New yttrium rich regions were formed in microstructure of TiNi alloy. The improved properties of this alloy by the yttrium addition could be attributed to the formation of these regions. The results showed that there was an optimum content for addition of yttrium between 2% and 5% （in wt%）, and above this content the improvement in properties of TiNi became minor.展开更多
The colon is an alternative graft organ for esophageal reconstruction.The present study reviewed our experience with the colon interposition for esophageal replacement following corrosive ingestion,to evaluate the out...The colon is an alternative graft organ for esophageal reconstruction.The present study reviewed our experience with the colon interposition for esophageal replacement following corrosive ingestion,to evaluate the outcomes of colon interposition based on our surgical experience. The clinical data of 119 patients who underwent colon interposition for esophageal replacement from January 2005 to March 2017 were retrospectively analyzed. The routes of the colon interposition were retrosternal in 119 (100%). The median operative time was 390 min (range: 290-610 min) and the median blood loss was 615 mL (range:270-2500 mL). Of these 119 patients, the cervical anastomosis was performed at the hypopharynx (n=20,16.8%), the larynx (n=3,2.5%), and the cervical esophagus (n=96, 80.7%). Five patients experienced cervical anastomotic leakage (4 cases for esophagus-colon, and one for hypopharynx-colon).One patient experienced wound infection of the abdominal wall. Three patients had injury of recurrent laryngeal nerve and hoarseness. Three patients had stress ulcer with bleeding and treated with octreotide. Two patients suffered from incomplete intestinal obstruction. The postoperative follow-up was made for 12 months in all patients and all of them were alive. In conclusion, The colon is well-suited for esophageal reconstruction. The selection of the colon graft should be flexible and be based on the inspection of blood supply and the length needed. We must therefore make every effort to reduce the number of postoperative complications, and improve the quality of life for patients.展开更多
Plasma electrolytic oxidation(PEO)is a promising surface treatment to generate adherent and thick anti-corrosive coating on light-weight metals(Al,Mg,Ti,etc.)using an eco-friendly alkaline electrolyte.High energy plas...Plasma electrolytic oxidation(PEO)is a promising surface treatment to generate adherent and thick anti-corrosive coating on light-weight metals(Al,Mg,Ti,etc.)using an eco-friendly alkaline electrolyte.High energy plasma,however,inevitably generates porous structures that limit their practical performance.The present study proposes a straight-forward simple method by utilizing sub-zero electrolyte(268 K)to alter the plasma characteristics during formation of the protective coating on AZ31 Mg alloy via PEO with a comparison to the electrolyte at room temperature(298 K).In refrigerated electrolyte,the formation of micro-defects is suppressed relatively at the expense of low coating growth,which is measured to be twice lower than that at 298 K due to the temperature-dependent soft plasma discharges contributing to the development of the present coating.As a consequence,corrosion resistance of the sample processed at 268 K is superior to that of 298K,implying that the effect of coating thickness is less dominant than that of compactness.This phenomenon is interpreted in relation to the ionic movement and oxide solidification controlled by soft plasma discharges arising from the temperature gradient between electrolyte and surface of the substrate during PEO.展开更多
Co30Cr8W1.6C3Ni1.4Si coatings were fabricated on Ti6Al4V alloy using a laser thermal spraying(LTS).The surface and cross-section morphologies,phases and bonding strength of obtained coatings were investigated using sc...Co30Cr8W1.6C3Ni1.4Si coatings were fabricated on Ti6Al4V alloy using a laser thermal spraying(LTS).The surface and cross-section morphologies,phases and bonding strength of obtained coatings were investigated using scanning electronic microscopy(SEM),X-ray diffraction(XRD),and scratch test,respectively.The effects of laser power on the coefficients of friction(COFs)and corrosive-wear behaviors of Co30Cr8W1.6C3Ni1.4Si coatings were investigated using a wear tester in 3.5%NaCl solution,and the electrochemical corrosion performance was analyzed using an electrochemical workstation.The experimental results show that the Co30Cr8W1.6C3Ni1.4Si coating is bonded with the substrate in the metallurgical form,and the bonding strengths of Co30Cr8W1.6C3Ni1.4Si coatings fabricated at the laser power of 1000,1200,and 1400 W are 76.5,56.5,and 55.6 N,respectively.The average COFs of Co30Cr8W1.6C3Ni1.4Si coatings fabricated at the laser power of 1000,1200,and 1400 W are 0.769,0.893,and 0.941,respectively;and the corresponding wear rates are 0.267×105,0.3178×105,and 0.325×105μm3/Nm,respectively,which increases with the increase of laser power,the wear mechanism is primarily abrasive wear.The corrosion potential of Co30Cr8W1.6C3Ni1.4Si coatings fabricated at the laser power of 1000,1200,and 1400 W is-0.05,-0.25,and-0.31 V,respectively,higher than-0.45 V of substrate which enhances the electrochemical corrosion resistance of substrate.展开更多
文摘Magnesium and its alloys have gained relevance for their light-weight combined with a high value of strength-to-weight ratio,which makes them useful in fields such as aerospace,automotive as well as biomedical engineering.Unfortunately,the poor corrosion resistance of Mg-alloys limits their wide acceptance.Advanced composite coatings which are self-healing,superhydrophobic anti corrosive,and wear resistant are new synthetic materials for abating these challenges.The superimposed superhydrophobic surfaces help in minimizing their water contact,thus slowing down the electrochemical reactions on the surface of the alloys,while their self-healing characteristics autonomously aid in the repair of any induced micro-crack,defect or damage towards ensuring the metal's long-term protection.In addition,the integration of wear-resistant materials further improves the durability of coatings under mechanical stress.The most recent research efforts have been directed towards the preparation of multifunctional composites,with an emphasis on nanomaterials,functional polymers,and state-of-the-art fabrication techniques in order to take advantage of their synergistic effects.Some of the methods that have so far exhibited promising potentials in fabricating these materials include the sol-gel method,layer-by-layer assembly,and plasma treatments.However,most of the fabricated products are still faced with significant challenges ranging from long-term stability to homogeneous adhesion of the coatings and their scalability for industrial applications.This review discusses the recent progress and the relationship between corrosion inhibition and self-healing efficiencies of wear resistant polymer nanocomposite coatings.Some challenges related to optimizing coating performance were also discussed.In addition,future directions ranging from the consideration of bioinspired designs,novel hybrid nanocomposite materials,and environmentally sustainable solutions integrated with smart protective coatings were also proposed as new wave technologies that can potentially revolutionize the corrosion protection offered by Mg alloys while opening up prospects for improved performance and sustainability.
基金fnancial support by the National Natural Science Foundation of China(Grant No.42176209)the Natural Science Foundation of Shandong Province(Grant No.ZR2021MD064).
文摘Cu–Ni and Cu–Co–Ni superhydrophobic films were constructed on the surface of B10 copper–nickel alloy welded joints using a two-step process of electrodeposition and stearic acid modification.The chemical composition of the film surface was determined using surface characterization techniques.The corrosion resistance of the films was characterized using electrochemical impedance spectroscopy,potentiodynamic polarization,and scanning Kelvin probe microscopy at multiple scales.The thermal stability,mechanical stability,and self-cleaning properties of the films were also characterized.It was determined that the Cu–Co–Ni superhydrophobic film exhibited the best performance,with a static water contact angle of 159.3°,a roll-off angle of 2.3°,a charge transfer resistance 3300 times higher than the substrate,a self-corrosion current density nearly three orders of magnitude lower,and a surface Kelvin potential increase of 420 mV.The film demonstrated good thermal stability,excellent mechanical stability,and outstanding self-cleaning properties.Combining with previous studies,it was found that Co elements in the film contribute to the formation of a uniform and dense film,Ni elements enhance the adhesion and corrosion resistance between the films,and the combination of Co and Ni elements promotes uniform surface potential and further improves the corrosion resistance and interfilm adhesion of the films.
基金supported by the Ministry of Education and Science of Ukraine(No.0123U101834)support in the framework of the“EU Next generation EU through the Recovery and Resilience Plan for Slovakia”(Nos.09I03-03-V01-00061 and 09I03-03-V01-00099)。
文摘Wrought and laser powder bed fusion(LPBF)Ti−6Al−4V(Ti-6-4)specimens were comparatively evaluated,with the objective to determine LPBF Ti−6Al−4V’s suitability for biomedical applications.Testing included nanoindentation,cyclic polarization in simulated body fluid(SBF,37°C),and dry and SBF“ball-on-plate”sliding.Wrought Ti-6-4 exhibited a lamellarα+βmicrostructure,whereas LPBF Ti-6-4 displayed a fine-grainedα′-martensite microstructure.LPBF Ti-6-4 demonstrated~3%higher indentation modulus and~32%higher hardness,while wrought Ti-6-4 showed~8%higher plasticity.Both alloys exhibited low corrosion rates(10−5 mA/cm^(2)order)and true passivity(10−4 mA/cm^(2)order).No localized corrosion was observed in either two alloys,except for occasional metastable pitting in the LPBF alloy.However,LPBF Ti-6-4 presented higher corrosion rate and passive current,ascribed to its martensitic structure.During dry sliding,LPBF Ti-6-4 exhibited~14%lower volume loss compared to wrought Ti-6-4.Sliding in SBF increased volume losses for both alloys,with wear resistances nearly equalized,as the advantage of LPBF Ti-6-4 decreased due to more intense wear-accelerated corrosion induced by the stressed martensite.Overall,the results demonstrate the suitability of LPBF Ti-6-4 for biomedical uses.
文摘BACKGROUND Corrosive ingestion remains an important global pathology with high morbidity and mortality.Data on the acute management of adult corrosive injuries from sub-Saharan Africa is scarce,with international investigative algorithms,relying heavily on computed tomography(CT),having limited availability in this setting.AIM To investigate the corrosive injury spectrum in a low-resource setting and the applicability of parameters for predicting full-thickness(FT)necrosis and mortality.METHODS A retrospective analysis of a prospective corrosive injury registry(March 1,2017–October 31,2023)was performed to include all adult patients with acute corrosive ingestion managed at a single,academic referral centre in Cape Town,South Africa.Patient demographics,corrosive ingestion details,initial investigations,management,and short-term outcomes were described using descriptive statistics while multivariate analysis with receiver operator characteristic area under the curve graphs(ROC AUC)were used to identify factors predictive of FT necrosis and 30-day mortality.RESULTS One-hundred patients were included,with a mean age of 32 years(SD:11.2 years)and a male predominance(65.0%).The majority(73.0%)were intentional suicide attempts.Endoscopy on admission was the most frequent initial investigation performed(95 patients),while only 17 were assessed with CT.Seventeen patients had full thickness necrosis at surgery,of which eleven underwent emergency resection and six were palliated.Thirty-day morbidity and mortality were 27.0%and 14.0%,respectively.Patients with full thickness necrosis and those with an established perforation had a 30-day mortality of 58.8%and 91.0%,respectively.Full thickness necrosis was associated with a cumulative 2-year survival of only 17.6%.Multivariate analyses with ROC AUC showed admission endoscopy findings,CT findings,and blood gas findings(pH,base excess,lactate),to all have significant predictive value for full thickness necrosis,with endoscopy proving to have the best predictive value(AUC 0.850).CT and endoscopy findings were the only factors predictive of early mortality,with CT performing better than endoscopy(AUC 0.798 vs 0.759).CONCLUSION Intentional corrosive injuries result in devastating morbidity and mortality.Locally,early endoscopy remains the mainstay of severity assessment,but referral for CT imaging should be considered especially when blood gas findings are abnormal.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(no.2022R1A2C1006743)。
文摘The self-assembly of hybrid inorganic-organic materials on stationary platforms plays a critical role in improving their structural stability and wide usability.In this work,a novel two-step hydrothermal approach is proposed for synthesizing stable and advanced hybrid coatings on metal-oxide platforms through the surface modification of layered double hydroxide(LDH)films using novel metal-organic frameworks(MOFs).Initially,Mg-Al LDH nanocontainers,grown on a magnesium oxide layer produced through plasma electrolytic oxidation(PEO)of AZ31 Mg alloy substrate,were intercalated with cobalt via an oxidation route,providing the metallic coordination center for the MOF formation.In the subsequent step,a pioneering technique is introduced,utilizing tryptophan as the organic linker for the first time at a pH of 10.The self-assembly of cobalt-tryptophan complex,driven by the strong bonding between electrophilic sites of monomers and nucleophilic sites,facilitated the formation of a MOF network having a cloud-like structure on the surface of MgAl LDH's film.The resulting MOF-LDH encapsulation containers demonstrate exceptional electrochemical stability when exposed to a 3.5 wt.%NaCl solution,surpassing the performance of PEO and pure LDH coatings.This enhanced stability is attributed to the development of a dense top layer and a stable composition within the self-assembled MOF,effectively sealing flaws and preventing the infiltration of corrosive ions into the underlying metallic substrate.The formation mechanism of MOFs on LDH galleries is investigated using density functional theory calculations.
基金supported by the National Natural Science Foundation of China(No.22209054)the Natural Science Foundation of Hunan Province(Nos.2023JJ30017 and 2023JJ30030)the Natural Science Foundation of Changsha(No.kq2208223)。
文摘Owing to the significant potential of alkalin seawater electrolysis for converting surplus power into eco friendly hydrogen fuel,we developed bifunctional elec trodes that integrate low-crystalline NiFe LDHs and amorphous NiFe alloy on a Ni foam(NF)substrate to enhance this process.Driven by the battery-like charac teristics of NiFe LDHs,an anti-corrosive and active oute layer of NiFe^(vac)OOH continuously forms over time in th hybrid on the anode for the oxygen evolution reaction(OER),effectively mitigating powder shedding caused by corrosion induced by multiple anions in seawater.Mean while,the strong bond between the hybrid and the NF substrate maintains intact hybrid coatings to ensure a rel atively high overall conductivity of the electrodes,signif icantly reducing the negative effects of structura degradation during the OER and hydrogen evolution reaction(HER),as well as the accumulation of contami nants on the electrode surfaces.In long-term tests,thes bifunctionalhybridelectrodesmaintained stable performance,even at a high current density o500 mA·cm^(-2).The cell voltage increased by only 88 m V over 1000 h to 1.970 V during saline electrolysis and by103 mV over 500 h to 2.062 V during seawater electroly sis.Hence,this study provides valuable insights into efficient and stable seawater electrolysis using NiFe LDHs–NiFe alloy hybrids.
文摘Coatings or surface modification are a very attractive strategy for protecting metal against corrosion in construction,chemical industries,automotive,ships and aerospace applications.The original idea to mitigate the corrosion process aims to prepare a coating or pretreatment layer to isolate the corrosive environment and the traditional field of metal materials to provide physical barrier.Nowadays,with the development of the novel coating composition,machine learning(ML)techniques prediction,which was endowed unprecedented functionality,such as self healing,self-reporting,self-lubrication and anti-fouling properties,is driving the field of application also extend to microelectronics and energy(anode material,metal batteries).
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(No.2022R1A2C1006743).
文摘Advanced hybrid materials with unique properties are essential for addressing the demands of increasingly complex applications.Despite their importance,the self-assembly of layered double hydroxides(LDH)with metallic oxide nanoparticles and dicarboxylic acids is constrained by a limited understanding of the formation mechanisms and difficulties in evaluating their anticorrosive performance.In this study,we developed a novel anticorrosive system by intercalating CeNiLDH with a complex of vanadium pentoxide(V2O5)nanoparticles and(2E)-but-2-enedioic acid((2E)-BDA)on a MgO layer created through plasma-electrolysis of AZ31 Mg alloy.This system was compared with LDH films intercalated with either V2O5 or(2E)-BDA alone.The intercalation of LDH with V_(2)O_(5)and(2E)-BDA resulted in a flower-like structure,while modification with their complex led to a more compact,cloud-like formation.These cloud-like structures,driven by enhanced absorption and robust hydrogen bonding throughout the hierarchical network,effectively suppress corrosion by delaying the movement of corrosive anions.This was reflected in a polarization resistance of 1.51×10^(10)Ω·cm^(2),which is approximately two orders of magnitude times higher than the resistance of the unmodified LDH film(3.41×10^(8)Ω·cm^(2)).Additionally,the corrosion current density(icorr)of the VOBDA sample showed a decrease by four orders of magnitude compared to the unmodified LDH sample,emphasizing the superior anticorrosive performance of this hybrid coating.Density functional theory(DFT)was used to elucidate the bonding and formation mechanisms between LDH and the inorganic-organic complex.
文摘In this paper, through the data treatment of correlation coefficients and the clustering technique of pattern recognition, both the matrix of correlation coefficients and the pedigree of factor clusters show that some factors affecting soil corrosivity are interrelated closely, and some independent relatively. The data analytical method used in this paper has certain assistance to the selection of major soil factors during the prediction and evaluation of soil corrosivity.
文摘BACKGROUND Aorto-oesophageal fistula(AOF)are uncommon and exceedingly rare after corrosive ingestion.The authors report a case of AOF after corrosive ingestion that survived.A comprehensive literature review was performed to identify all cases of AOF after corrosive ingestion to determine the incidence of this condition,how it is best managed and what the outcomes are.CASE SUMMARY A previously healthy 30-year-old male,presented with a corrosive oesophageal injury after drain cleaner ingestion.He did not require acute surgical resection,but developed long-segment oesophageal stricturing,which was initially managed with cautious dilatation and later stenting.An AOF was suspected at endoscopy performed two months after the ingestion,when the patient represented with massive upper gastrointestinal bleeding.The fistula was confirmed on computerised tomographic angiography.The initial bleeding at endoscopy was temporised by oesophageal stenting;a second stent was placed when bleeding recurred later the same day.The stenting successfully achieved temporary bleeding control,but resulted in sudden respiratory distress,which was found to be due to left main bronchus compression caused by the overlapping oesophageal stents.Definitive bleeding control was achieved by endovascular aortic stent-grafting.A retrosternal gastroplasty was subsequently performed to achieve gastrointestinal diversion to reduce the risk of stent-graft sepsis.He was subsequently successfully discharged and remains well one year post injury.CONCLUSION AOF after corrosive ingestion is exceedingly rare,with a very high mortality.Most occur weeks to months after the initial corrosive ingestion.Conservative management is ill-advised.
基金supported financially by the National Key Research and Development Program of China (No. 2017YFB0702100)the Natural Science Foundation of Liaoning Province (No. 20170540666)
文摘Galvanic corrosion of tri-metallic couples is more complicated than that of bi-metallic couples. In this study, the effect of the pH of corrosive media on the galvanic corrosion of 2024 A1 alloy/Q235 mild steel/304 stainless steel tri-metallic couples was investigated using potentiodynamic polarization, scanning electron microscopy, scanning vibrating electrode technique and a multi-channel galvanic corrosion meter. The results show that 2024 always acts as the only anode in 3.5 wt% NaCl at pH 5.56,9.72 and 12.0, while both Q235 and 2024 act as anodes at pH 2.39 in the initial stage and then the role of Q235 changes at longer coupling time, which can be attributed to the effect of pH on the surface film of 2024. It is also found that the galvanic current density of a tri-metallic couple is the superposition of two bi-metallic couples when cathodic reactions are controlled by the diffusion of oxygen, otherwise it is smaller than that of the sum of two bi-metallic couples. The localized corrosion instead of uniform corrosion of anodic metal is accelerated by galvanic corrosion.
基金Supported by National Natural Science Foundation of China(Grant No.51175408)
文摘Tribological properties of impregnated graphite are greatly influenced by preparation technology and working conditions and it’s highly susceptible to corrosion environmental impacts,but the experimental research about it are few.In this paper,three kinds of impregnated graphite samples are prepared with different degree of graphitization,the tribological properties of these samples in the dry friction environment and in a corrosive environment are analyzed and contrasted.The tribo-test results show that the friction coefficient of samples is reduced and the amount of wear of samples increase when the graphitization degree of samples increases in dry friction condition.While in a corrosive environment（samples are soaked N2O4）,the friction coefficient and amount of wear are changed little if the graphitization degree of samples are low.If the degree of graphitization increase,the friction coefficient and amount of wear of samples increase too,the amount of wear is 2 to 3 times as the samples tested in the non-corrosive environment under pv value of 30MPa？m/s.The impregnated graphite,which friction coefficient is stable and graphitization degree is in mid level,such#2,is more appropriate to have a work in the corrosion conditions.In this paper,preparation and tribological properties especially in corrosive environment of the impregnated graphite is studied,the research conclusion can provide an experimental and theoretical basis for the selection and process improvement of graphite materials,and also provide some important design parameters for contact seal works in a corrosive environment.
基金Supported by the National Basic Research Program of China(973 Program)(No.2014CB643304)the National Natural Science Foundation of China(No.41576080)the Key Research and Development Program of Shandong Province(No.2018GHY115003)
文摘Anaerobic, aerobic, and facultative bacteria are all present in corrosive environments. However, as previous studies to address corrosion in the marine environment have largely focused on anaerobic bacteria, limited attention has been paid to the composition and function of aerobic and facultative bacteria in this process. For analysis in this study, ten samples were collected from rust layers on steel plates that had been immersed in seawater for diff erent periods (i.e., six months and eight years) at Sanya and Xiamen, China. The cultivable aerobic bacterial community structure as well as the number of sulfate-reducing bacteria (SRB) were analyzed in both cases, while the proportion of facultative SRB among the isolated aerobic bacteria in each sample was also evaluated using a novel approach. Bacterial abundance results show that the proportions are related to sea location and immersion time;abundances of culturable aerobic bacteria (CAB) and SRB from Sanya were greater in most corrosion samples than those from Xiamen, and abundances of both bacterial groups were greater in samples immersed for six months than for eight years. A total of 213 isolates were obtained from all samples in terms of CAB community composition, and a phylogenetic analysis revealed that the taxa comprised four phyla and 31 genera. Bacterial species composition is related to marine location;the results show that Firmicutes and Proteobacteria were the dominant phyla, accounting for 98.13% of the total, while Bacillus and Vibrio were the dominant genera, accounting for 53.06% of the total. An additional sixfacultative SRB strains were also screened from the isolates obtained and were found to encompass the genus Vibrio (four strains), Staphylococcus (one strain), and Photobacterium (one strain). It is noteworthy that mentions of Photobacterium species have so far been absent from the literature, both in terms of its membership of the SRB group and its relationship to corrosion.
基金Project supported by the Western Transportation Construction Sci-ence&Technology Program,Ministry of Transport of China(No.201332849A090)
文摘This paper deals with a correction method for corrosive crack width caused by non-uniform corrosion. Considering the corrosion cracking characteristics of a reinforced concrete structure, a correction model of corrosive crack width involving the mutual impacts between adjacent measuring points is established. The calculation model for steel bar corrosion rate for single point is obtained through quantitative analysis and accelerated corrosion tests on more than 70 reinforced cubic members. Two methods are suggested by combining two models, the correction and the corrosion calculation ones. Electrolyte accelerated cor- rosion tests on seven beams are carried out to verify these methods. The experimental results show that the ratio between the maximum corrosion rate by the indirect method and the measured average value ranges from 1.4 to 2.4, and the indirect method is shown to be an effective method for calculating the maximum corrosion rate.
文摘Expandable rock bolts are widely used in hard rock mines as an efficient ground control product.However, capacity and service life can be significantly reduced if the metallic body is subjected to corrosion.In some hard rock mines in the U.S., highly corrosive ground conditions exist, and it has been reported that inflatable rock bolts have corroded within a few months after installation.To provide mining industry a cost-effective inflatable bolt and combat the corrosion issues, Jennmar Corporation, Inc.,and its subsidiary Keystone Mining Services, LLC(KMS), analyzed corroded bolt samples, identified root causes, evaluated properties of various coating materials, and developed a new inflatable rock bolt,Python M3^(TM), that is protected with an innovative PyFlexU2^(TM)coating.The new generation Python M3^(TM) features improved steel chemistry for reliable performance, modified profile for better inflation, and surface preparation and coating application.The PyFlexU2^(TM)is impervious to liquid and air, durable, and UV resistant.With a flexible, adhesive, and highly corrosion-resistant undercoating, and a very hard sacrificial surface coating, the PyFlexU2^(TM)coating system provides the Python M3^(TM)superior protection against chemical corrosion and physical scratch damage.The under-coating has exceptional flexibility and adhesion to prevent coating micro-cracks or fractures after bolt inflation and possesses excellent corrosion resistance to acids(pH < 3), alkalis(p H > 11), fuels, and salt solvents.The corrosion and scratch resistant PyFlexU2^(TM)coating offers very effective bolt protection for extra longevity in highly corrosive environments.The Python M3^(TM)coated with PyFlexU2^(TM)has been tested in the most challenging conditions,including laboratory corrosion tests in extreme acidic and basic solvents, rock slurry, and borehole scratch insertion tests.With demonstrated corrosion and scratch resistance, the product has been greatly welcomed by hard rock mines in the West and is currently installed in large scale.This paper identifies the root causes of the bolt corrosion, discusses the analysis process, and details laboratory and underground tests carried out on the Python M3^(TM)coated with PyFlexU2^(TM).The Python M3^(TM)and PyFlexU2^(TM) are subjects covered by pending U.S.Patent Applications assigned to FCI Holdings Delaware, LLC.
基金Iranian Nanotechnology Initiative (INI) for finical support of the research work
文摘The corrosion, corrosive wear and dry sliding wear of nanocomposites, are extremely complicated and involve various chemical, physical anbd mechanical factors. The aim of this work is to investigate the effects of nanosized SiC content on the hardness, dry sliding wear, corrosion and corrosive wear of Al/SiC nanocomposites synthesized by mechanical milling cold pressing and hot extrusion. The corrosion resistance of these composites in 3%NaCl solution was investigated by electrochemical polarization testing and their dry sliding as well as corrosive wear resistance in the same solution was evaluated using a pin-on-disc tester. The microstructures of the samples and their worn surfaces were examined using scanning electron microscopy. It was shown that the dry sliding wear and corrosion resistance of these nanocomposites were improved with the increase of SiC content. It was concluded that due to the lubrication effect of the solution, both the friction coefficient and frictional heat that might soften the material were reduced. In addition, the improved strength of the nanocomposites combined with their better corrosion resistance contributed to their increased corrosive wear resistance, compared with the base alloy. The prominent wear mechanism in the unreinforced alloy was adhesive wear, in the Al/SiC nanocomposites, the wear mechanism changed to abrasive.
文摘TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. In this paper, it was demonstrated that by addition of yttrium, hardness properties and resistance to wear and corrosive wear of TiNi alloy were improved. New yttrium rich regions were formed in microstructure of TiNi alloy. The improved properties of this alloy by the yttrium addition could be attributed to the formation of these regions. The results showed that there was an optimum content for addition of yttrium between 2% and 5% （in wt%）, and above this content the improvement in properties of TiNi became minor.
文摘The colon is an alternative graft organ for esophageal reconstruction.The present study reviewed our experience with the colon interposition for esophageal replacement following corrosive ingestion,to evaluate the outcomes of colon interposition based on our surgical experience. The clinical data of 119 patients who underwent colon interposition for esophageal replacement from January 2005 to March 2017 were retrospectively analyzed. The routes of the colon interposition were retrosternal in 119 (100%). The median operative time was 390 min (range: 290-610 min) and the median blood loss was 615 mL (range:270-2500 mL). Of these 119 patients, the cervical anastomosis was performed at the hypopharynx (n=20,16.8%), the larynx (n=3,2.5%), and the cervical esophagus (n=96, 80.7%). Five patients experienced cervical anastomotic leakage (4 cases for esophagus-colon, and one for hypopharynx-colon).One patient experienced wound infection of the abdominal wall. Three patients had injury of recurrent laryngeal nerve and hoarseness. Three patients had stress ulcer with bleeding and treated with octreotide. Two patients suffered from incomplete intestinal obstruction. The postoperative follow-up was made for 12 months in all patients and all of them were alive. In conclusion, The colon is well-suited for esophageal reconstruction. The selection of the colon graft should be flexible and be based on the inspection of blood supply and the length needed. We must therefore make every effort to reduce the number of postoperative complications, and improve the quality of life for patients.
基金the Mid-Level Researcher National Project of the National Research Foundation(NRF)funded by the Ministry of Science and ICT,Republic of Korea(NRF-2020R1A2C2004192)supported partly by the Competency Development Program for Industry Specialist of the Korea Institute for Advancement of Technology(KIAT)funded by the Ministry of Trade,Industry,and Energy,Republic of Korea(P0002019)。
文摘Plasma electrolytic oxidation(PEO)is a promising surface treatment to generate adherent and thick anti-corrosive coating on light-weight metals(Al,Mg,Ti,etc.)using an eco-friendly alkaline electrolyte.High energy plasma,however,inevitably generates porous structures that limit their practical performance.The present study proposes a straight-forward simple method by utilizing sub-zero electrolyte(268 K)to alter the plasma characteristics during formation of the protective coating on AZ31 Mg alloy via PEO with a comparison to the electrolyte at room temperature(298 K).In refrigerated electrolyte,the formation of micro-defects is suppressed relatively at the expense of low coating growth,which is measured to be twice lower than that at 298 K due to the temperature-dependent soft plasma discharges contributing to the development of the present coating.As a consequence,corrosion resistance of the sample processed at 268 K is superior to that of 298K,implying that the effect of coating thickness is less dominant than that of compactness.This phenomenon is interpreted in relation to the ionic movement and oxide solidification controlled by soft plasma discharges arising from the temperature gradient between electrolyte and surface of the substrate during PEO.
基金Funded by the Key Research and Development Project of Jiangsu Province(BE2016052)。
文摘Co30Cr8W1.6C3Ni1.4Si coatings were fabricated on Ti6Al4V alloy using a laser thermal spraying(LTS).The surface and cross-section morphologies,phases and bonding strength of obtained coatings were investigated using scanning electronic microscopy(SEM),X-ray diffraction(XRD),and scratch test,respectively.The effects of laser power on the coefficients of friction(COFs)and corrosive-wear behaviors of Co30Cr8W1.6C3Ni1.4Si coatings were investigated using a wear tester in 3.5%NaCl solution,and the electrochemical corrosion performance was analyzed using an electrochemical workstation.The experimental results show that the Co30Cr8W1.6C3Ni1.4Si coating is bonded with the substrate in the metallurgical form,and the bonding strengths of Co30Cr8W1.6C3Ni1.4Si coatings fabricated at the laser power of 1000,1200,and 1400 W are 76.5,56.5,and 55.6 N,respectively.The average COFs of Co30Cr8W1.6C3Ni1.4Si coatings fabricated at the laser power of 1000,1200,and 1400 W are 0.769,0.893,and 0.941,respectively;and the corresponding wear rates are 0.267×105,0.3178×105,and 0.325×105μm3/Nm,respectively,which increases with the increase of laser power,the wear mechanism is primarily abrasive wear.The corrosion potential of Co30Cr8W1.6C3Ni1.4Si coatings fabricated at the laser power of 1000,1200,and 1400 W is-0.05,-0.25,and-0.31 V,respectively,higher than-0.45 V of substrate which enhances the electrochemical corrosion resistance of substrate.
