At present,carbon capture and storage(CCS)is the only mature and commercialized technology capable of effectively and economically reducing greenhouse gas emissions to achieve a significant and immedi-ate impact on th...At present,carbon capture and storage(CCS)is the only mature and commercialized technology capable of effectively and economically reducing greenhouse gas emissions to achieve a significant and immedi-ate impact on the CO_(2) level on Earth.Notably,long-term geological storage of captured CO_(2) has emerged as a primary storage method,given its minimal impact on surface ecological environments and high level of safety.The integrity of CO_(2) storage wellbores can be compromised by the corrosion of steel casings and degradation of cement in supercritical CO_(2) storage environments,potentially leading to the leakage of stored CO_(2) from the sites.This critical review endeavors to establish a knowledge foundation for the cor-rosion and materials degradation associated with geological CO_(2) storage through an in-depth examina-tion and analysis of the environments,operation,and the state-of-the-art progress in research pertaining to the topic.This article discusses the physical and chemical properties of CO_(2) in its supercrit-ical phase during injection and storage.It then introduces the principle of geological CO_(2) storage,consid-erations in the construction of storage systems,and the unique geo-bio-chemical environment involving aqueous media and microbial communities in CO_(2) storage.After a comprehensive analysis of existing knowledge on corrosion in CO_(2) storage,including corrosion mechanisms,parametric effects,and corro-sion rate measurements,this review identifies technical gaps and puts forward potential avenues for fur-ther research in steel corrosion within geological CO_(2) storage systems.展开更多
Nanostructured Al_(2)O_(3)-10wt.%TiO_(2)-nCeO_(2)ceramic coatings(where n is 0 wt.%,0.2 wt.%,0.5 wt.%,and 0.8 wt.%)were prepared on a 304 stainless steel substrate using atmospheric plasma spraying.The phase compositi...Nanostructured Al_(2)O_(3)-10wt.%TiO_(2)-nCeO_(2)ceramic coatings(where n is 0 wt.%,0.2 wt.%,0.5 wt.%,and 0.8 wt.%)were prepared on a 304 stainless steel substrate using atmospheric plasma spraying.The phase composition and microstructure of the coatings were characterized using an X-ray diffractometer and a scanning electron microscope.The corrosion resistance of the coatings was as-sessed through electrochemical experiments and chloride ion corrosion tests.The results indicated that the coatings comprised both partially and fully melted regions,with spherical particles and pores present on the coating surfaces.The incorporation of CeO_(2)en-hanced the melting of the sprayed powder during the spraying process.When the CeO_(2)content was 0.2 wt.%,the melting of the sprayed powder was optimal.The porosity of the coating was minimized to 2.45%.CeO_(2)also positively influenced the grain refine-ment of the coating;at 0.2 wt.%CeO_(2),the grain size was at its minimum.The grain size of this coating was calculated to be 21.135 nm using the Scherrer formula.This coating demonstrated the best corrosion resistance,with a corrosion potential of-596.31 mV and a corrosion current density of 1.65×10^(-6)A/cm^(2),resulting in a weight loss of 0.0170 g due to chloride ion corrosion.展开更多
The corrosion behavior of Ni-Co-CeO_(2) composite coating was investigated under a simulated high-temperature marine atmosphere alongside Ni-Co coating. The corrosion kinetics, phase composition and microstructure evo...The corrosion behavior of Ni-Co-CeO_(2) composite coating was investigated under a simulated high-temperature marine atmosphere alongside Ni-Co coating. The corrosion kinetics, phase composition and microstructure evolution of the coatings were analyzed. A multi-layered oxide scale formed due to the synergistic corrosion by H_(2)O and NaCl. The growth mechanism of the Co_(3)O_(4), Fe_(3)O_(4), Fe_(2)O3, CoFe_(2)O_(4), NiFe_(2)O_(4) and NiO in the scale was proposed according to the distribution of the CeO_(2) particles. Compared to Ni-Co cating, the Ni-Co-CeO_(2) coating exhibited superior corrosion resistance in the H_(2)O/NaCl steam, which is beacause the CeO_(2) exerted a blocking effect on retarding the diffusion of Fe atoms and corrosive medium, contributing to a reduced corrosion rate and an improved oxide adhesion compared to Ni-Co coating.展开更多
Copper is a versatile material,commonly utilized in power transmission and electronic devices,but its relative high reactivity necessitates a long-lasting protective technique.Here,we report a method that combines pla...Copper is a versatile material,commonly utilized in power transmission and electronic devices,but its relative high reactivity necessitates a long-lasting protective technique.Here,we report a method that combines plasma-enhanced non-equilibrium magnetron sputtering physical vapor deposition(PEUMS-PVD)and anodization to construct a self-healing three-dimensional Ti/Al-doped TiO_(2)nanotubes/Ti_(3)AlC_(2)coating on the surface of Cu substrates.This novel strategy enhances the corrosion resistance of copper substrates in marine environments,with corrosion current densities of up to 4.5643×10^(−8)A/cm^(2).Among them,the doping of nano-aluminum particles makes the coating self-healing.The mechanistic analysis of the corrosion behaviors during early immersion experiments was conducted using electrochemical noise,and revealed that during the initial stages of coating immersion,uniform corrosion predominates,with a minor occurrence of localized corrosion.展开更多
An idea hits us that in-situ synthesizing ceramic phase at intergranular regions of RE-Fe-B alloys should be beneficial to the performance of the materials against corrosion,and in this work a new nanoscale(Zr,Ti)B_(2...An idea hits us that in-situ synthesizing ceramic phase at intergranular regions of RE-Fe-B alloys should be beneficial to the performance of the materials against corrosion,and in this work a new nanoscale(Zr,Ti)B_(2)with space and point groups of P6/mmm and Fmmm,respectively,was successfully synthesized in NdCeFeB sintered magnets.The hcp-structured(Zr,Ti)B_(2)phases are present in a stripe-like shape.Some of(Zr,Ti)B_(2)are developed at interfaces,and the others exist inside grain boundary phase.They coexist with REFe_(2)and RE-rich phases at intergranular regions.When proximity to RE2Fe14B grains,their orientation relationships obey[001]_(Nd_(2)Fe_(14)B)‖[110](Zr,Ti)B_(2).The formation of(Zr,Ti)B_(2)generates significant local compressive stress,being 8.48 GPa,and plenty of reliefs are developed inside the RE2Fe14B grains.The in-situ formed(Zr,Ti)B_(2)modifies the magnet microstructure,lessens the favorable sites for absorption reaction,narrows reaction channels,and reduces the potential difference between intergranular phase and main phase.Such favorable factors greatly enhance the corrosion resistance with an icorrdecrement by 70%in comparison to the unmodified magnet.These new discoveries are thought to be able to provide an insight into the method of potentially improving properties of magnets.展开更多
[目的]探究miR-552-3p调节SETD2对肾细胞癌786-O细胞转移活性的影响。[方法]通过实时的荧光定量PCR方式对正常肾小管上皮细胞株HK-2细胞、透明细胞肾细胞癌细胞株786-O细胞、RCC23细胞、Caki-2细胞中的miR-552-3p与SETD2表达情况进行检...[目的]探究miR-552-3p调节SETD2对肾细胞癌786-O细胞转移活性的影响。[方法]通过实时的荧光定量PCR方式对正常肾小管上皮细胞株HK-2细胞、透明细胞肾细胞癌细胞株786-O细胞、RCC23细胞、Caki-2细胞中的miR-552-3p与SETD2表达情况进行检测。将786-O细胞分为miR NC组、miR-552-3p inhibitor组、pcDNA3.1 NC组以及pcDNA3.1 SETD2组。通过CCK-8实验分析786-O细胞增殖能力;Transwell实验和划痕实验分析786-O细胞侵袭和迁移能力;荧光素酶报告基因实验分析786-O细胞中miR-552-3p与SETD2的靶向关系。[结果]与正常肾小管上皮细胞株相比,miR-552-3p在透明细胞肾细胞癌细胞株中高表达(0.22±0.03 vs 0.92±0.05 vs 0.87±0.06 vs 0.88±0.11),而SETD2在透明细胞肾细胞癌细胞株中低表达(0.93±0.05 vs 0.31±0.03 vs 0.32±0.07 vs 0.29±0.06)。与miR NC组比较,miR-552-3p inhibitor组的786-O细胞的增殖活性降低(2.21±0.08 vs 1.36±0.11)、侵袭和迁移能力降低(103.19±9.38 vs 52.09±5.76个;73.19%±6.35%vs 22.12%±5.21%)。与pcDNA3.1 NC组比较,pcDNA3.1 SETD2组的786-O细胞的增殖活性降低、侵袭和迁移能力降低(P<0.05)。荧光素酶活性测定显示,和miR NC组比较,在SETD2-WT组中转染miR-552-3p mimic后荧光素酶活性降低(P<0.05)。[结论]miR-552-3p在透明细胞肾细胞癌细胞中高表达,而SETD2低表达。miR-552-3p能够抑制透明细胞肾细胞癌细胞的体外增殖、迁移和侵袭,并且这一作用与miR-552-3p抑制SETD2的表达相关。展开更多
The study investigated the application of radiofrequency(RF)-sputtered TiO2 coatings at various temperatures to enhance the hydrophobicity and corrosion resistance of Al6061 alloy.The research aimed to establish a cor...The study investigated the application of radiofrequency(RF)-sputtered TiO2 coatings at various temperatures to enhance the hydrophobicity and corrosion resistance of Al6061 alloy.The research aimed to establish a correlation between the coating process and the resulting surface properties.Surface roughness and wettability were quantified with a surface profilometer and goniometer.Additionally,chemical boiling and salt spray corrosion tests were conducted to evaluate any topographical changes during these procedures.The analysis further involved the use of field-emission scanning electron microscopy(FESEM),energy-dispersive spectroscopy(EDS),and X-ray diffraction(XRD)techniques to characterize the deposited coatings.The findings indicated that the TiO2 coating applied at 500℃exhibited the highest water contact angle and superior corrosion resistance compared to other temperatures.Surface characterization confirmed that this specific TiO_(2) coating at 500℃ effectively delays corrosion due to its hydrophobic behavior,making it durable for industrial applications.展开更多
Trace La element was introduced in Al-20Mg_(2)Si composites to regulate the microstructure and corrosion performance.The modification mechanism of trace La and the corrosion behavior of the newly developed composites ...Trace La element was introduced in Al-20Mg_(2)Si composites to regulate the microstructure and corrosion performance.The modification mechanism of trace La and the corrosion behavior of the newly developed composites were systematically investigated by thermal analysis,microstructural observations and electrochemical tests.Our study reveals that the addition of only 0.10%La can refine the size of the primary Mg_(2)Si phase from 77.6 to 26.7μm,modify its morphology from a coarse dendrite to a fine truncated octahedron and reduce the corrosion current density from 5.96μA cm^(-2) to 3.03μA cm^(-2).Trace La refines the primary Mg_(2)Si phase size by forming a tiny LaAlSi phase which can provide effective heterogeneous nuclei for the primary Mg_(2)Si phase during solidification.Excess La atoms can selectively adsorb on the{100}facets of the primary Mg_(2)Si phase and suppress the preferential growth of the Mg_(2)Si phase,eventually resulting in the morphological transition of the primary Mg_(2)Si phase from dendrite to truncated octahedron shape.The enhanced corrosion resistance of the La micro-alloyed Al-20Mg_(2)Si composites can be attributed to the formation of stronger protective surface oxide films and finer primary Mg_(2)Si phase.The protective oxide films can effectively hinder the penetration of the corrosive medium and the finer primary Mg_(2)Si phase can weaken the localized corrosion tendency of the Al-Mg_(2)Si composites.展开更多
In order to explore the corrosion mechanism of Al_(2)O_(3)-C refractories in the mold flux bearing MnO,the immersion test of Al_(2)O_(3)-C refractories in CaO-SiO2-CaF2-MnO slag with different MnO contents was carried...In order to explore the corrosion mechanism of Al_(2)O_(3)-C refractories in the mold flux bearing MnO,the immersion test of Al_(2)O_(3)-C refractories in CaO-SiO2-CaF2-MnO slag with different MnO contents was carried out at 1550℃.The results show that Mn particles were observed in the slag after experiment,due to the reduction of MnO by graphite in refractories.Large amounts of graphite were observed at the interface between refractories and slag,indicating that the oxidation of graphite is limited by the poor contact between graphite and molten slag.Therefore,the oxidation of graphite is not the main cause of damage to refractories.A small quantity of CaO·2Al_(2)O_(3)(CA_(2))and CaO·6Al_(2)O_(3)(CA_(6))adjacent to Al_(2)O_(3) grain was detected at the slag/reaction layer interface.CA_(2) and CA_(6) possess relatively high melting points,which is beneficial to hindering the further penetration of slag.However,the dissolution of Al_(2)O_(3) into slag is still the main cause for refractories damage.The increase in the MnO content of mold slag decreases the viscosity and then results in the severe corrosion of Al_(2)O_(3)-C bricks.展开更多
The double-layer NiCr-Cr_(3)C_(2)/Ni-Zn-Al_(2)O_(3) coatings with sufficient corrosion and wear resistance were prepared on low carbon steel substrates.The intermediate layers Ni-Zn-Al_(2)O_(3) were fabricated by usin...The double-layer NiCr-Cr_(3)C_(2)/Ni-Zn-Al_(2)O_(3) coatings with sufficient corrosion and wear resistance were prepared on low carbon steel substrates.The intermediate layers Ni-Zn-Al_(2)O_(3) were fabricated by using low-pressure cold spray (LPCS) method to improve the salt fog corrosion resistance properties of the supersonic plasma spray (SPS) NiCr-Cr_(3)C_(2) coatings.The friction and wear performance for the double-layer and single-layer NiCr-Cr_(3)C_(2) coatings were carried out by line-contact reciprocating sliding,respectively.Combined with the coating surface analysis techniques,the effect of the salt fog corrosion on the tribological properties of the double-layer coatings was studied.The results showed that the double-layer coatings exhibited better wear resistance than that of the single-layer coatings,due to the better corrosion resistance of the intermediate layer;the wear mass losses of the double-layer coatings was reduced by 70%than that of the single layer coatings and the wear mechanism of coatings after salt fog corrosion conditions is mainly corrosion wear.展开更多
To solve the problem of poor high-temperature service performance caused by low carbonization of MgO-C refractories,low-carbon MgO–C refractories with excellent thermal shock,oxidation and corrosion resistances were ...To solve the problem of poor high-temperature service performance caused by low carbonization of MgO-C refractories,low-carbon MgO–C refractories with excellent thermal shock,oxidation and corrosion resistances were successfully designed by using SiC whiskers as reinforcing phases and introducing micro-Al_(2)O_(3) powders as additives.The results indicated that the addition of micro-Al_(2)O_(3) powders optimized the internal structure of the material,like the columnar β-Si_(3)N_(4) with a stepped distribution and the mosaic structure formed between granular and flaky Mg_(2)SiO_(4),which synergistically strengthened and toughened the material and gave the material excellent mechanical properties and thermal shock resistance.Specifically,the cold modulus of rupture and cold crushing strength after thermal shock were increased by 4.1 and 20.3 MPa,respectively.Moreover,the addition of micro-Al_(2)O_(3) powders promoted the formation of fine particles of Mg_(2)SiO_(4),MgAl_(2)O_(4) and MgO,as well as a dense protective layer of Mg_(2)SiO_(4) in the material under high-temperature environment.Furthermore,spinel and high-temperature solid solution were formed in the corrosion environment.The oxidation and corrosion resistances were greatly improved by 41%and 15%,respectively.展开更多
During CO_(2)transportation and storage,metal equipment such as oilfield pipelines suffers from severe CO_(2)corrosion,especially in harsh downhole injection equipment.In this study,we investigated the corrosion behav...During CO_(2)transportation and storage,metal equipment such as oilfield pipelines suffers from severe CO_(2)corrosion,especially in harsh downhole injection equipment.In this study,we investigated the corrosion behavior of oil well tubing in a high-temperature,high-pressure(HTHP)CO_(2)-containing environment.The evolution of the corrosion scale was also examined under different flow regimes.The results reveal a lower corrosion rate at 150℃compared to 80℃under different flow regimes,with localized corrosion intensifying as temperature and rotational speeds(vrs)increase.The temperature also induces the corrosion scale conversion of aragonite-type CaCO_(3)(80℃)to calcite-type CaCO_(3)(150℃).Specifically,the variation of the corrosion rate and the corrosion scale evolution can be attributed to the vortices within the reactor.The intact vortex cells enhance mass transfer while also promoting nucleation and growth of CaCO3.However,when vrsexceeds the critical Reynolds number,the vortex cells are disrupted,resulting in viscous dissipation and a reduced corrosion rate.展开更多
随着碳捕集、利用与封存(carbon capture,utilization and storage,CCUS)技术在油田的持续应用,CO_(2)腐蚀井下管柱现象引起高度重视,亟需适用于高CO_(2)分压环境下考虑腐蚀速率随时间变化影响的腐蚀速率模型。通过模拟温度80~120℃、CO...随着碳捕集、利用与封存(carbon capture,utilization and storage,CCUS)技术在油田的持续应用,CO_(2)腐蚀井下管柱现象引起高度重视,亟需适用于高CO_(2)分压环境下考虑腐蚀速率随时间变化影响的腐蚀速率模型。通过模拟温度80~120℃、CO_(2)分压15~30 MPa条件下Q125、3Cr和13Cr管材的腐蚀,建立了这3种管材考虑温度、CO_(2)分压和腐蚀时间影响的腐蚀速率预测模型,并对Q125套管进行了安全服役寿命预测。结果表明:同一CO_(2)分压下,Q125、3Cr管材腐蚀速率随温度增加呈先增后减的趋势,13Cr管材腐蚀速率随温度增加而增大;3种管材腐蚀速率均随CO_(2)分压增加而增大。Q125管材匀速和变速两种腐蚀速率模型均适用,3Cr和13Cr管材适用变速腐蚀模型。Q125套管的抗拉安全服役年限随着CO_(2)分压的增加而逐渐降低,抗拉安全服役年限最短约为12 a。展开更多
The effect of Ca^2＋ on CO2 corrosion to X65 pipeline steel was investigated in the simulated stratum water of an oil field containing different concentrations of Ca^2＋. It is found that Ca^2＋ can enhance the corros...The effect of Ca^2＋ on CO2 corrosion to X65 pipeline steel was investigated in the simulated stratum water of an oil field containing different concentrations of Ca^2＋. It is found that Ca^2＋ can enhance the corrosion rate, especially in the Ca^2＋ concentration from 256 to 512 mg/L, which can be attributed to the growing grain size and loosing structure of corrosion scales with increasing Ca^2＋ concentration. X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS） investigations reveal that a complex carbonate （Fe, Ca）CO3 forms at high Ca^2＋ concentration due to the gradual replacement of Fe^2＋ in FeCO3 by Ca^2＋.展开更多
The corrosion behavior of the 110S tube steel in the environments of high H2 S and CO2 content was inves- tigated by using a high-temperature and high-pressure autoclave, and the corrosion products were characterized ...The corrosion behavior of the 110S tube steel in the environments of high H2 S and CO2 content was inves- tigated by using a high-temperature and high-pressure autoclave, and the corrosion products were characterized by scanning electron microscopy and X ray diffraction technique. The results showed that all of the corrosion products under the test conditions mainly consisted of different types of iron sulfides such as pyrrhotite of Fe0.95 S, mackinaw- ite of FeS0.9, Fe0. 985 S and FeS, and the absence of iron carbonate in the corrosion scales indicated that the corrosion process was controlled by H2S corrosion. The corrosion rate of the 110S steel decreased firstly and then increased with the rising of temperature. The minimum corrosion rate occurred at 110 ℃. When the H2 S partial pressure PH2s below 9 MPa, the corrosion rate declined with the increase of PH2s. While over 9 MPa, a higher PH2s resulted in a faster corrosion process. With the increasing of the CO2 partial pressure, the corrosion rate had an increasing trend. The morphologies of the corrosion scales had a good accordance with the corrosion rates.展开更多
文摘At present,carbon capture and storage(CCS)is the only mature and commercialized technology capable of effectively and economically reducing greenhouse gas emissions to achieve a significant and immedi-ate impact on the CO_(2) level on Earth.Notably,long-term geological storage of captured CO_(2) has emerged as a primary storage method,given its minimal impact on surface ecological environments and high level of safety.The integrity of CO_(2) storage wellbores can be compromised by the corrosion of steel casings and degradation of cement in supercritical CO_(2) storage environments,potentially leading to the leakage of stored CO_(2) from the sites.This critical review endeavors to establish a knowledge foundation for the cor-rosion and materials degradation associated with geological CO_(2) storage through an in-depth examina-tion and analysis of the environments,operation,and the state-of-the-art progress in research pertaining to the topic.This article discusses the physical and chemical properties of CO_(2) in its supercrit-ical phase during injection and storage.It then introduces the principle of geological CO_(2) storage,consid-erations in the construction of storage systems,and the unique geo-bio-chemical environment involving aqueous media and microbial communities in CO_(2) storage.After a comprehensive analysis of existing knowledge on corrosion in CO_(2) storage,including corrosion mechanisms,parametric effects,and corro-sion rate measurements,this review identifies technical gaps and puts forward potential avenues for fur-ther research in steel corrosion within geological CO_(2) storage systems.
基金supported by the National Natural Science Foundation of China(Grant No.52375387).
文摘Nanostructured Al_(2)O_(3)-10wt.%TiO_(2)-nCeO_(2)ceramic coatings(where n is 0 wt.%,0.2 wt.%,0.5 wt.%,and 0.8 wt.%)were prepared on a 304 stainless steel substrate using atmospheric plasma spraying.The phase composition and microstructure of the coatings were characterized using an X-ray diffractometer and a scanning electron microscope.The corrosion resistance of the coatings was as-sessed through electrochemical experiments and chloride ion corrosion tests.The results indicated that the coatings comprised both partially and fully melted regions,with spherical particles and pores present on the coating surfaces.The incorporation of CeO_(2)en-hanced the melting of the sprayed powder during the spraying process.When the CeO_(2)content was 0.2 wt.%,the melting of the sprayed powder was optimal.The porosity of the coating was minimized to 2.45%.CeO_(2)also positively influenced the grain refine-ment of the coating;at 0.2 wt.%CeO_(2),the grain size was at its minimum.The grain size of this coating was calculated to be 21.135 nm using the Scherrer formula.This coating demonstrated the best corrosion resistance,with a corrosion potential of-596.31 mV and a corrosion current density of 1.65×10^(-6)A/cm^(2),resulting in a weight loss of 0.0170 g due to chloride ion corrosion.
基金supported by the National Key Research and Development Programme(2023YFB3408200)the National Nature Science Foundation of China(52201076 and 52471077)+2 种基金the Guangdong Provincial Key R&D Programme(2023B0909020002)the Guangdong Basic and Applied Basic Research Foundation(2021A1515111065,2021B1515120014 and 2022A1515010934)the Fundamental Research Funds for the Central Universities(21623216 and 11623216).
文摘The corrosion behavior of Ni-Co-CeO_(2) composite coating was investigated under a simulated high-temperature marine atmosphere alongside Ni-Co coating. The corrosion kinetics, phase composition and microstructure evolution of the coatings were analyzed. A multi-layered oxide scale formed due to the synergistic corrosion by H_(2)O and NaCl. The growth mechanism of the Co_(3)O_(4), Fe_(3)O_(4), Fe_(2)O3, CoFe_(2)O_(4), NiFe_(2)O_(4) and NiO in the scale was proposed according to the distribution of the CeO_(2) particles. Compared to Ni-Co cating, the Ni-Co-CeO_(2) coating exhibited superior corrosion resistance in the H_(2)O/NaCl steam, which is beacause the CeO_(2) exerted a blocking effect on retarding the diffusion of Fe atoms and corrosive medium, contributing to a reduced corrosion rate and an improved oxide adhesion compared to Ni-Co coating.
基金Projects(42106051,42006046,U2106206) supported by the National Natural Science Foundation of ChinaProject(22373501D) supported by Hebei Provincial Key R&D Program,China。
文摘Copper is a versatile material,commonly utilized in power transmission and electronic devices,but its relative high reactivity necessitates a long-lasting protective technique.Here,we report a method that combines plasma-enhanced non-equilibrium magnetron sputtering physical vapor deposition(PEUMS-PVD)and anodization to construct a self-healing three-dimensional Ti/Al-doped TiO_(2)nanotubes/Ti_(3)AlC_(2)coating on the surface of Cu substrates.This novel strategy enhances the corrosion resistance of copper substrates in marine environments,with corrosion current densities of up to 4.5643×10^(−8)A/cm^(2).Among them,the doping of nano-aluminum particles makes the coating self-healing.The mechanistic analysis of the corrosion behaviors during early immersion experiments was conducted using electrochemical noise,and revealed that during the initial stages of coating immersion,uniform corrosion predominates,with a minor occurrence of localized corrosion.
基金Project supported by the National Natural Science Foundation of China(52174346)Natural Science Foundation of Shandong Province(ZR2021ME031,ZR2022QE115)Innovation Capability Enhancement Project for Technology Oriented Small and Medium Sized Enterprises of Shandong Province(2022TSGC2586)。
文摘An idea hits us that in-situ synthesizing ceramic phase at intergranular regions of RE-Fe-B alloys should be beneficial to the performance of the materials against corrosion,and in this work a new nanoscale(Zr,Ti)B_(2)with space and point groups of P6/mmm and Fmmm,respectively,was successfully synthesized in NdCeFeB sintered magnets.The hcp-structured(Zr,Ti)B_(2)phases are present in a stripe-like shape.Some of(Zr,Ti)B_(2)are developed at interfaces,and the others exist inside grain boundary phase.They coexist with REFe_(2)and RE-rich phases at intergranular regions.When proximity to RE2Fe14B grains,their orientation relationships obey[001]_(Nd_(2)Fe_(14)B)‖[110](Zr,Ti)B_(2).The formation of(Zr,Ti)B_(2)generates significant local compressive stress,being 8.48 GPa,and plenty of reliefs are developed inside the RE2Fe14B grains.The in-situ formed(Zr,Ti)B_(2)modifies the magnet microstructure,lessens the favorable sites for absorption reaction,narrows reaction channels,and reduces the potential difference between intergranular phase and main phase.Such favorable factors greatly enhance the corrosion resistance with an icorrdecrement by 70%in comparison to the unmodified magnet.These new discoveries are thought to be able to provide an insight into the method of potentially improving properties of magnets.
文摘[目的]探究miR-552-3p调节SETD2对肾细胞癌786-O细胞转移活性的影响。[方法]通过实时的荧光定量PCR方式对正常肾小管上皮细胞株HK-2细胞、透明细胞肾细胞癌细胞株786-O细胞、RCC23细胞、Caki-2细胞中的miR-552-3p与SETD2表达情况进行检测。将786-O细胞分为miR NC组、miR-552-3p inhibitor组、pcDNA3.1 NC组以及pcDNA3.1 SETD2组。通过CCK-8实验分析786-O细胞增殖能力;Transwell实验和划痕实验分析786-O细胞侵袭和迁移能力;荧光素酶报告基因实验分析786-O细胞中miR-552-3p与SETD2的靶向关系。[结果]与正常肾小管上皮细胞株相比,miR-552-3p在透明细胞肾细胞癌细胞株中高表达(0.22±0.03 vs 0.92±0.05 vs 0.87±0.06 vs 0.88±0.11),而SETD2在透明细胞肾细胞癌细胞株中低表达(0.93±0.05 vs 0.31±0.03 vs 0.32±0.07 vs 0.29±0.06)。与miR NC组比较,miR-552-3p inhibitor组的786-O细胞的增殖活性降低(2.21±0.08 vs 1.36±0.11)、侵袭和迁移能力降低(103.19±9.38 vs 52.09±5.76个;73.19%±6.35%vs 22.12%±5.21%)。与pcDNA3.1 NC组比较,pcDNA3.1 SETD2组的786-O细胞的增殖活性降低、侵袭和迁移能力降低(P<0.05)。荧光素酶活性测定显示,和miR NC组比较,在SETD2-WT组中转染miR-552-3p mimic后荧光素酶活性降低(P<0.05)。[结论]miR-552-3p在透明细胞肾细胞癌细胞中高表达,而SETD2低表达。miR-552-3p能够抑制透明细胞肾细胞癌细胞的体外增殖、迁移和侵袭,并且这一作用与miR-552-3p抑制SETD2的表达相关。
文摘The study investigated the application of radiofrequency(RF)-sputtered TiO2 coatings at various temperatures to enhance the hydrophobicity and corrosion resistance of Al6061 alloy.The research aimed to establish a correlation between the coating process and the resulting surface properties.Surface roughness and wettability were quantified with a surface profilometer and goniometer.Additionally,chemical boiling and salt spray corrosion tests were conducted to evaluate any topographical changes during these procedures.The analysis further involved the use of field-emission scanning electron microscopy(FESEM),energy-dispersive spectroscopy(EDS),and X-ray diffraction(XRD)techniques to characterize the deposited coatings.The findings indicated that the TiO2 coating applied at 500℃exhibited the highest water contact angle and superior corrosion resistance compared to other temperatures.Surface characterization confirmed that this specific TiO_(2) coating at 500℃ effectively delays corrosion due to its hydrophobic behavior,making it durable for industrial applications.
基金supported by the National Natural Science Foundation of China(Nos.52201051 and 52201295)。
文摘Trace La element was introduced in Al-20Mg_(2)Si composites to regulate the microstructure and corrosion performance.The modification mechanism of trace La and the corrosion behavior of the newly developed composites were systematically investigated by thermal analysis,microstructural observations and electrochemical tests.Our study reveals that the addition of only 0.10%La can refine the size of the primary Mg_(2)Si phase from 77.6 to 26.7μm,modify its morphology from a coarse dendrite to a fine truncated octahedron and reduce the corrosion current density from 5.96μA cm^(-2) to 3.03μA cm^(-2).Trace La refines the primary Mg_(2)Si phase size by forming a tiny LaAlSi phase which can provide effective heterogeneous nuclei for the primary Mg_(2)Si phase during solidification.Excess La atoms can selectively adsorb on the{100}facets of the primary Mg_(2)Si phase and suppress the preferential growth of the Mg_(2)Si phase,eventually resulting in the morphological transition of the primary Mg_(2)Si phase from dendrite to truncated octahedron shape.The enhanced corrosion resistance of the La micro-alloyed Al-20Mg_(2)Si composites can be attributed to the formation of stronger protective surface oxide films and finer primary Mg_(2)Si phase.The protective oxide films can effectively hinder the penetration of the corrosive medium and the finer primary Mg_(2)Si phase can weaken the localized corrosion tendency of the Al-Mg_(2)Si composites.
基金the National Natural Science Foundation of China(52274305 and U1860205)Young Elite Scientists Sponsorship Program by CAST(2022QNRC001).
文摘In order to explore the corrosion mechanism of Al_(2)O_(3)-C refractories in the mold flux bearing MnO,the immersion test of Al_(2)O_(3)-C refractories in CaO-SiO2-CaF2-MnO slag with different MnO contents was carried out at 1550℃.The results show that Mn particles were observed in the slag after experiment,due to the reduction of MnO by graphite in refractories.Large amounts of graphite were observed at the interface between refractories and slag,indicating that the oxidation of graphite is limited by the poor contact between graphite and molten slag.Therefore,the oxidation of graphite is not the main cause of damage to refractories.A small quantity of CaO·2Al_(2)O_(3)(CA_(2))and CaO·6Al_(2)O_(3)(CA_(6))adjacent to Al_(2)O_(3) grain was detected at the slag/reaction layer interface.CA_(2) and CA_(6) possess relatively high melting points,which is beneficial to hindering the further penetration of slag.However,the dissolution of Al_(2)O_(3) into slag is still the main cause for refractories damage.The increase in the MnO content of mold slag decreases the viscosity and then results in the severe corrosion of Al_(2)O_(3)-C bricks.
基金Fundamental Research Funds for Central Universities Project (No. 1CX05021A)Shandong Provincial Key R&D Plan Project (No. 2GHY15108)Shandong Postdoctoral Innovation Project and Qingdao Postdoctoral Applied Research Project。
文摘The double-layer NiCr-Cr_(3)C_(2)/Ni-Zn-Al_(2)O_(3) coatings with sufficient corrosion and wear resistance were prepared on low carbon steel substrates.The intermediate layers Ni-Zn-Al_(2)O_(3) were fabricated by using low-pressure cold spray (LPCS) method to improve the salt fog corrosion resistance properties of the supersonic plasma spray (SPS) NiCr-Cr_(3)C_(2) coatings.The friction and wear performance for the double-layer and single-layer NiCr-Cr_(3)C_(2) coatings were carried out by line-contact reciprocating sliding,respectively.Combined with the coating surface analysis techniques,the effect of the salt fog corrosion on the tribological properties of the double-layer coatings was studied.The results showed that the double-layer coatings exhibited better wear resistance than that of the single-layer coatings,due to the better corrosion resistance of the intermediate layer;the wear mass losses of the double-layer coatings was reduced by 70%than that of the single layer coatings and the wear mechanism of coatings after salt fog corrosion conditions is mainly corrosion wear.
基金the Scientific Research Fund of Hunan Provincial Education Department(22B0856)the Hengyang"Xiaohe"Science and Technology Talent Special Project([2023]45)+3 种基金the Guidance Plan Project of Hengyang City([2023]40)the National Natural Science Foundation of China(U20A20239)the College Students'Innovation and Entrepreneurship Training Project(S202311528055)the Characteristic Application Discipline of Material Science Engineering in Hunan Province([2022]351).
文摘To solve the problem of poor high-temperature service performance caused by low carbonization of MgO-C refractories,low-carbon MgO–C refractories with excellent thermal shock,oxidation and corrosion resistances were successfully designed by using SiC whiskers as reinforcing phases and introducing micro-Al_(2)O_(3) powders as additives.The results indicated that the addition of micro-Al_(2)O_(3) powders optimized the internal structure of the material,like the columnar β-Si_(3)N_(4) with a stepped distribution and the mosaic structure formed between granular and flaky Mg_(2)SiO_(4),which synergistically strengthened and toughened the material and gave the material excellent mechanical properties and thermal shock resistance.Specifically,the cold modulus of rupture and cold crushing strength after thermal shock were increased by 4.1 and 20.3 MPa,respectively.Moreover,the addition of micro-Al_(2)O_(3) powders promoted the formation of fine particles of Mg_(2)SiO_(4),MgAl_(2)O_(4) and MgO,as well as a dense protective layer of Mg_(2)SiO_(4) in the material under high-temperature environment.Furthermore,spinel and high-temperature solid solution were formed in the corrosion environment.The oxidation and corrosion resistances were greatly improved by 41%and 15%,respectively.
基金supported by the National Natural Science Foundation in China(52434002,42176209,52074339)the Natural Science Foundation of Shandong Province(ZR2021ME007)+1 种基金the Opening Fund of Shandong Key Laboratory of Oilfield Chemistrythe Fundamental Research Funds for the Central Universities(19CX05006A)。
文摘During CO_(2)transportation and storage,metal equipment such as oilfield pipelines suffers from severe CO_(2)corrosion,especially in harsh downhole injection equipment.In this study,we investigated the corrosion behavior of oil well tubing in a high-temperature,high-pressure(HTHP)CO_(2)-containing environment.The evolution of the corrosion scale was also examined under different flow regimes.The results reveal a lower corrosion rate at 150℃compared to 80℃under different flow regimes,with localized corrosion intensifying as temperature and rotational speeds(vrs)increase.The temperature also induces the corrosion scale conversion of aragonite-type CaCO_(3)(80℃)to calcite-type CaCO_(3)(150℃).Specifically,the variation of the corrosion rate and the corrosion scale evolution can be attributed to the vortices within the reactor.The intact vortex cells enhance mass transfer while also promoting nucleation and growth of CaCO3.However,when vrsexceeds the critical Reynolds number,the vortex cells are disrupted,resulting in viscous dissipation and a reduced corrosion rate.
基金supported by the National Natural Science Foundation of China (No.50571012)
文摘The effect of Ca^2＋ on CO2 corrosion to X65 pipeline steel was investigated in the simulated stratum water of an oil field containing different concentrations of Ca^2＋. It is found that Ca^2＋ can enhance the corrosion rate, especially in the Ca^2＋ concentration from 256 to 512 mg/L, which can be attributed to the growing grain size and loosing structure of corrosion scales with increasing Ca^2＋ concentration. X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS） investigations reveal that a complex carbonate （Fe, Ca）CO3 forms at high Ca^2＋ concentration due to the gradual replacement of Fe^2＋ in FeCO3 by Ca^2＋.
基金Sponsored by Key National Science and Technology Specific Projects of China(2008ZX05017-002)
文摘The corrosion behavior of the 110S tube steel in the environments of high H2 S and CO2 content was inves- tigated by using a high-temperature and high-pressure autoclave, and the corrosion products were characterized by scanning electron microscopy and X ray diffraction technique. The results showed that all of the corrosion products under the test conditions mainly consisted of different types of iron sulfides such as pyrrhotite of Fe0.95 S, mackinaw- ite of FeS0.9, Fe0. 985 S and FeS, and the absence of iron carbonate in the corrosion scales indicated that the corrosion process was controlled by H2S corrosion. The corrosion rate of the 110S steel decreased firstly and then increased with the rising of temperature. The minimum corrosion rate occurred at 110 ℃. When the H2 S partial pressure PH2s below 9 MPa, the corrosion rate declined with the increase of PH2s. While over 9 MPa, a higher PH2s resulted in a faster corrosion process. With the increasing of the CO2 partial pressure, the corrosion rate had an increasing trend. The morphologies of the corrosion scales had a good accordance with the corrosion rates.
