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
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
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
To elucidate the effects of Cl^(-)and Ca^(2+) on the corrosion and scale formation of 3Cr steel in CO_(2) floodingproduced fluid,corrosion weight loss experiments,and titration experiments were conducted.The resulting...To elucidate the effects of Cl^(-)and Ca^(2+) on the corrosion and scale formation of 3Cr steel in CO_(2) floodingproduced fluid,corrosion weight loss experiments,and titration experiments were conducted.The resulting products were characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).This study examined the corrosion and scaling behavior of 3Cr steel under the influence of Cl^(-)and Ca^(2+).The results indicate that both Cl^(-)and Ca^(2+)promote the corro sion of 3Cr steel.Notably,Cl^(-)diminishes the promoting effect of Ca^(2+)on corro sion and inhibits scaling,revealing a mutual enhancement between corrosion and scaling.The mechanisms of localized corrosion under varying concentrations of Cl^(-)and Ca^(2+)differ;under-scale corrosion occurs in environments with 5000 mg·L^(-1) Cl^(-),while Cl^(-)induced corrosion is observed in 20000 mg·L^(-1) Cl^(-)environments.This study highlights that under the synergistic effects of Cl^(-),Ca^(2+),and scaling processes,the protective product film dissolves,thereby influencing both corrosion and scaling processes.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
Formation characteristic of CO2 corrosion product layer on the surface of P110 steel was investigated in simulated oilfield environment using massqoss experiment, potentiodynamic polarization curve, impedance spectros...Formation characteristic of CO2 corrosion product layer on the surface of P110 steel was investigated in simulated oilfield environment using massqoss experiment, potentiodynamic polarization curve, impedance spectroscopy, and SEM micrograph analysis. Samples of different times up to 240 h were tested during exposure. Corrosion product was primarily composed of Fe（Ca, Mg）（CO3 ）2, which was distinguished by two layers. With an increase in the exposure time, the charge transfer resistance and polarization resistance increased progressively, the uniform cor- rosion rate decreased, and the corrosion reaction was controlled by the diffusion process instead of the activation process. All phenomena were attributed to the formation of the protective corrosion product layer. More compact and lower porosity of the layer made it more difficult to transfer and diffuse through the corrosion product layer for the charges and ions. Similar results were obtained bv electrochemical test and mass-loss experiment.展开更多
In order to investigate the CO2 corrosion behavior and the grooving corrosion susceptibility of electric resistance welded tubes of the Q125 grade, the high temperature and high pressure autoclave was employed to cond...In order to investigate the CO2 corrosion behavior and the grooving corrosion susceptibility of electric resistance welded tubes of the Q125 grade, the high temperature and high pressure autoclave was employed to conduct CO2 corrosion experiments for the welded joint. The mechanisms of grooving corrosion and the factors influencing grooving corrosion susceptibility were identified by electrochemical measurement, microstructure observation, residual stress examination, micro-region composition and orientation analysis. The CO2 corrosion results show that the corrosion resistance of the base material is the best, followed by heataffected zone and the welded seam is the worst. The grooving corrosion occurred in the welded seam, and the grooving corrosion susceptibility of welded seam is relativity high. The dominated reason for the grooving corrosion of the electric resistance welded joint is the notable inclusions consisting of MnS as the main content in the welded seam. The proportion of high-angle grain boundaries in the welding zone is higher than that of base metal and the heat affected zone, which plays an important role in the corrosion behavior of the welded seam.展开更多
目的 探究驱动蛋白家族成员2A(kinesin family member 2A,KIF2A)对肝癌细胞5-FU耐药的作用及其作用机制。方法 采用浓度梯度递增联合大剂量间断冲击的方法诱导肝癌细胞BEL7402对5-FU耐药,以构建耐药株BEL7402/5-FU。采用慢病毒技术构建K...目的 探究驱动蛋白家族成员2A(kinesin family member 2A,KIF2A)对肝癌细胞5-FU耐药的作用及其作用机制。方法 采用浓度梯度递增联合大剂量间断冲击的方法诱导肝癌细胞BEL7402对5-FU耐药,以构建耐药株BEL7402/5-FU。采用慢病毒技术构建KIF2A沉默的BEL7402/5-FU细胞。用Notch1/Hes1信号通路激动剂丙戊酸(valproic acid,VPA)对KIF2A沉默的BEL7402/5-FU细胞进行干预。用CCK-8实验、蛋白印迹法、免疫荧光、流式细胞术检测细胞活性、细胞凋亡率、KIF2A、cleaved-caspase-3、Notch1和Hes1的蛋白表达。结果 BEL7402/5-FU细胞具有强5-FU耐药性,其IC_(50)为344.2μmol/L,是BEL7402细胞的92倍(IC_(50)=3.730μmol/L)。与BEL7402细胞比较,BEL7402/5-FU细胞中KIF2A蛋白表达明显增加(P<0.001);与si-NC组比较,si-KIF2A组BEL7402/5-FU细胞活性明显下降(P<0.001)、凋亡率和cleaved-caspase-3蛋白表达明显增加(P<0.001),另外Notch1和Hes1蛋白表达明显减少(P<0.001);与si-NC+5-FU组比较,si-KIF2A+5-FU组BEL7402/5-FU细胞活性显著下降(P<0.001)、凋亡率显著增加(P<0.001);与si-KIF2A+5-FU组比较,si-KIF2A+5-FU+VPA组BEL7402/5-FU细胞活性明显提高(P<0.001)、凋亡率显著降低(P<0.001)、Notch1和Hes1蛋白表达量显著增加(P<0.001)。结论 KIF2A的沉默通过抑制Notch1/Hes1信号通路活性减弱BEL7402/5-FU细胞对5-FU的化疗耐药性。展开更多
A comparative study on the corrosion resistance of 17Ni/（NiFe2O4-10NiO） cermet inert anode prepared in differentsintering atmospheres was conducted in Na3AlF6-Al2O3 melt. The results indicate that the corrosion rate...A comparative study on the corrosion resistance of 17Ni/（NiFe2O4-10NiO） cermet inert anode prepared in differentsintering atmospheres was conducted in Na3AlF6-Al2O3 melt. The results indicate that the corrosion rates of NiFe2O4-based cermetanodes prepared in the vacuum and the atmosphere with oxygen content of 2×10^-3 （volume fraction） are 6.46 and 2.71 cm/a,respectively. Though there is a transition layer with lots of holes or pores, a densified layer is formed on the surface of anode due tosome reactions producing aluminates. For the anode prepared in the atmosphere with oxygen content of 2×10^-3, the thickness of thedensification layer （about 50 μm） is thicker than that （about 30 μm） formed on the surface of anode prepared in the vacuum. Thecontents of NiO and Fe（II） in NiFe2xO4-y-z increase with the decrease of oxygen content in sintering atmosphere, which reduces thecorrosion resistance of the material.展开更多
Polyamides containing thieno[2,3-b]thiophene moiety were prepared via a simple polycondensation reaction of the diaminothieno[2,3-b]thiophene monomer la with different kinds of diacid chlorides （including oxalyl, adi...Polyamides containing thieno[2,3-b]thiophene moiety were prepared via a simple polycondensation reaction of the diaminothieno[2,3-b]thiophene monomer la with different kinds of diacid chlorides （including oxalyl, adipoyl, sebacoyl, isophthaloyl, terephthaloyl, 4,4＇-azodibenzoyl, 3,3＇-azodibenzoyl, p-phenylene diacryloyl） in the presence of LiC1 and NMP as a solvent through lowtemperature solution polycondensation. The chemical structures of model compound and synthesized polyamides were confirmed by FTIR, nuclear magnetic resonance spectroscopy （including 1 H-NMR and 13 C-NMR） and elemental analysis. In addition, the thermal stability, crystallinity structure and surface morphology of synthesized polyamides were characterized via thermogravametric analysis （TGA）, wide-angle X-ray diffraction analysis （WAXD） and scanning electron microscopy （SEM）. Also, the corrosion inhibition behavior of selected examples ofpolyamides was investigated; the inhibitive effect of the investigated polymers for carbon steel in 1.0 mol＇L-1 HCI was studied using potentiodynamic polarization （PDP） and electrochemical impedance spectroscopy （EIS） methods. PDP results displayed that the polyamides containing thieno[2,3-b]thiophene moiety can be as mixed-type inhibitors. The inhibition efficiency （P, %） was found to be in the range from 67.13% to 96.01%. There is an increase in P by the synthesized polymers in comparison to the starting monomer. The adsorption of these polymers was found to obey Langmuir adsorption isotherm.展开更多
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
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
The corrosion behavior of 2 A02 Al alloy under simulated marine atmospheric environment has been studied using mass-gain, scanning electron microscope/energy dispersive spectroscopy(SEM/EDS), laser scanning confocal m...The corrosion behavior of 2 A02 Al alloy under simulated marine atmospheric environment has been studied using mass-gain, scanning electron microscope/energy dispersive spectroscopy(SEM/EDS), laser scanning confocal microscopy, X-ray diffraction spectroscopy and localized electrochemical methods. The results demonstrate that the relationship between the corrosion induced mass-gain and the corrosion time is in accordance with the power rule. The mass-gain increases gradually during the corrosion time,while the corrosion rate decreases. With ongoing of the corrosion, corrosion products film changed from a porous to a compact structure. The various spectroscopic data show that the corrosion products films composed mainly of Al(OH)_3, Al_2O_3 and AlCl_3. The electrochemical corrosion behavior of the 2 A02 Al alloy was studied by electrochemical impedance spectroscopy(EIS).展开更多
The poor corrosion resistance of magnesium(Mg)and its alloys limits their application in various fields.Micro arc oxidation(MAO)coatings can improve the corrosion resistance,but the pore defects and low surface hardne...The poor corrosion resistance of magnesium(Mg)and its alloys limits their application in various fields.Micro arc oxidation(MAO)coatings can improve the corrosion resistance,but the pore defects and low surface hardness make them susceptible to wear and accelerated corrosion during usage.In this study,a ZrO_(2)nanoparticles doped-MAO coating is prepared on the ZK61 Mg alloy by utilizing an MgF_(2)passivation layer to prevent ablation.The ZrO_(2)nanoparticles re-melt and precipitate due to local discharging,which produces evenly dispersed nanocrystals in the MAO coating.As a result,the hardness of the MAO coating with the appropriate ZrO_(2)concentration increases by over 10 times,while the wear rate decreases and corrosion resistance increases.With increasing ZrO_(2)concentrations,the corrosion potentials increase from−1.528 V of the bare ZK61 Mg alloy to−1.184 V,the corrosion current density decreases from 1.065×10^(–4)A cm^(–2)to 3.960×10^(–8)A cm^(–2),and the charge transfer resistance increases from 3.41×10^(2)Ωcm^(2)to 6.782×10^(5)Ωcm^(2).Immersion tests conducted in a salt solution for 28 d reveal minimal corrosion in contrast to severe corrosion on the untreated ZK61 Mg alloy.ZrO_(2)nanoparticles improve the corrosion resistance of MAO coatings by sealing pores and secondary strengthening of the corrosion product layer.展开更多
The regularities of atmospheric corrosion of A3 steel deposited with different amount of NaCl exposed to the air containing 1ppm SO2 at 80%RH and 25℃ were studied in laboratory. NaCl can accelerate the corrosion of A...The regularities of atmospheric corrosion of A3 steel deposited with different amount of NaCl exposed to the air containing 1ppm SO2 at 80%RH and 25℃ were studied in laboratory. NaCl can accelerate the corrosion of A3 steel obviously under such condition. The relationship between the weight loss of A3 steel and the amount of NaCl deposition can be well described by using a quadratic function. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy and electron dispersion X-ray analysis (SEM/EDAX) were used to characterize the corrosion products. In the absence of NaCl, FeSO4 · xH2O is the dominant corrosion products, while Fe3O4, FeSO4·H2O, β-FeOOH and γ-FeOOH dominate in the presence of NaCl.展开更多
Four kinds of P110 grade tube steels containing different chromium contents were designed to probe the in- fluence of Cr on the properties of tube steel. The microstrueture, mechanical properties and corrosion behavio...Four kinds of P110 grade tube steels containing different chromium contents were designed to probe the in- fluence of Cr on the properties of tube steel. The microstrueture, mechanical properties and corrosion behavior of the four kinds of P110 grade tube steels were studied deeply and thoroughly. The analysis of the mechanical properties indicated that tensile strength and yield strength of the steel plates were improved, while transverse and longitudinal impact energy and elongation first increased and then decreased when Cr content rose. The impact energy and elonga tion reached the peak when Cr content was 1 ~. Cr precipitates were found only in 3 ~ Cr steel, with （Nb, Ti）（C, N） or Nb（C,N） as the core of precipitation and then grew up. The corrosion experiments demonstrated that the scales on the four steels had a two layer structure under the corrosion of CO2 and H2 S. The outer layer was mainly com- posed of FeS or FeS1 x and the inner layer consisted of FeCOa and Cr compounds. Cr was rich in the inner layer and the Cr content of the inner layer increased with the Cr content in matrix. The enriched Cr enhanced the compactness of the scales, further hindering the diffusion of ions from liquid to the surface of steel, thus reducing corrosion rate.展开更多
To investigate the correlation between structure characteristics and wear resistance of CO2 corrosion product scales at high temperature and high pressure, an autoclave was used to prepare CO2 corrosion product scales...To investigate the correlation between structure characteristics and wear resistance of CO2 corrosion product scales at high temperature and high pressure, an autoclave was used to prepare CO2 corrosion product scales on N80 steel in carbon dioxide corrosion environment. The correlation between wear resistance of the scales and many other factors, such as temperature, pressure, morphology, structure, velocity of fluid medium, sand grain size, and so on, was comparatively analyzed by a self assembled wear device, and the scale morphologies before or after being worn were observed by scanning electron microscope （SEM）. And then the surface grain size and thickness of scale were measured. The results showed that the cross-section of the corrosion scale was of a double-layer structure, the outer layer of which was composed of regular crystals, whereas the inner layer was a thin scale of fine grains. The outer grain size and thickness of scale varied with temperature, and the initial wear loss was consistent with the surface grain size; at the same time, the total wear loss corresponded to the thickness of scale. Compared to wear resist- ance in different depths of the scale, it was found that the structure of scale was a double-layer structure in cross-section, and the wear resistance of inner layer was better than that of the outer layer; the closer the scale to the matrix, the greater was the wear resistance of scale; and the larger the size or the higher the rotary speed of solid grain in multiphase flowing medium, the more was the wear loss of scale.展开更多
Based on an analysis of the existing models of CO 2 corrosion in literatures and the autoclave simulative experiments, a predictive model of corrosion rate (r corr) in CO 2/H 2S corrosion for oil tubes has been ...Based on an analysis of the existing models of CO 2 corrosion in literatures and the autoclave simulative experiments, a predictive model of corrosion rate (r corr) in CO 2/H 2S corrosion for oil tubes has been established, in which r corr is expressed as a function of pH, temperature (T), pressure of CO 2 (P CO 2) and pressure of H 2S (P H 2S). The model has been verified by experimental data obtained on N80 steel. The improved features of the predictive model include the following aspects: (1) The influence of temperature on the protectiveness of corrosion film is taken into consideration for establishment of predictive model of the r corr in CO 2/H 2S corrosion. The Equations of scale temperature and scale factor are put forward, and they fit the experimental result very well. (2) The linear relationship still exists between ln r corr and ln P CO 2 in CO 2/H 2S corrosion (as same as that in CO 2 corrosion). Therefore, a correction factor as a function of P H 2S has been introduced into the predictive model in CO 2/H 2S corrosion. (3) The model is compatible with the main existing models.展开更多
The corrosion behavior of C100 steel in simulated environments with high H2S and CO2 content was studied through high-temperature and high-pressure autoclave, and the HaS stress corrosion cracking （SSC） resistance o...The corrosion behavior of C100 steel in simulated environments with high H2S and CO2 content was studied through high-temperature and high-pressure autoclave, and the HaS stress corrosion cracking （SSC） resistance of C100 steel was evaluated by SSC tests. Scanning electron microscopy （SEM）, transmission electron microscope （TEM） and X-ray diffraction （XRD） technique were employed to characterize the corrosion products and the metal matrix. The results indicate that all of the corrosion products in this investigation are mainly composed of different types of iron sulfide such as Fe0.95S, FeS0.9, F0.985S, Fe7S8 and FeS, and the absence of iron carbonate in the corrosion scales suggests that the corrosion process is governed by H2S corrosion. The corrosion rate decreases in the initial stage and then increases with the enhancement of the temperature. There exists a minimum corrosion rate at about 110 ℃. Under the partial pressure of H2S lower than 9 MPa, the corrosion rate decreases with the increase of P112S While over 9 MPa, a higher P112S will result in a faster corrosion process. When the applied stress is 72%, 80% and 85% of actual yield strength （AYS）, all tested specimens show no crack, which reveals a superior SSC resistance.展开更多
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.
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the support from the National Natural Science Foundation of China (51774249)the Sichuan Science and Technology Program (21JCQN0066)。
文摘To elucidate the effects of Cl^(-)and Ca^(2+) on the corrosion and scale formation of 3Cr steel in CO_(2) floodingproduced fluid,corrosion weight loss experiments,and titration experiments were conducted.The resulting products were characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).This study examined the corrosion and scaling behavior of 3Cr steel under the influence of Cl^(-)and Ca^(2+).The results indicate that both Cl^(-)and Ca^(2+)promote the corro sion of 3Cr steel.Notably,Cl^(-)diminishes the promoting effect of Ca^(2+)on corro sion and inhibits scaling,revealing a mutual enhancement between corrosion and scaling.The mechanisms of localized corrosion under varying concentrations of Cl^(-)and Ca^(2+)differ;under-scale corrosion occurs in environments with 5000 mg·L^(-1) Cl^(-),while Cl^(-)induced corrosion is observed in 20000 mg·L^(-1) Cl^(-)environments.This study highlights that under the synergistic effects of Cl^(-),Ca^(2+),and scaling processes,the protective product film dissolves,thereby influencing both corrosion and scaling processes.
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Item Sponsored by Program for New Century Excellent Talents in University of the Ministry of Education of China(NCET-07-0686)
文摘Formation characteristic of CO2 corrosion product layer on the surface of P110 steel was investigated in simulated oilfield environment using massqoss experiment, potentiodynamic polarization curve, impedance spectroscopy, and SEM micrograph analysis. Samples of different times up to 240 h were tested during exposure. Corrosion product was primarily composed of Fe（Ca, Mg）（CO3 ）2, which was distinguished by two layers. With an increase in the exposure time, the charge transfer resistance and polarization resistance increased progressively, the uniform cor- rosion rate decreased, and the corrosion reaction was controlled by the diffusion process instead of the activation process. All phenomena were attributed to the formation of the protective corrosion product layer. More compact and lower porosity of the layer made it more difficult to transfer and diffuse through the corrosion product layer for the charges and ions. Similar results were obtained bv electrochemical test and mass-loss experiment.
文摘In order to investigate the CO2 corrosion behavior and the grooving corrosion susceptibility of electric resistance welded tubes of the Q125 grade, the high temperature and high pressure autoclave was employed to conduct CO2 corrosion experiments for the welded joint. The mechanisms of grooving corrosion and the factors influencing grooving corrosion susceptibility were identified by electrochemical measurement, microstructure observation, residual stress examination, micro-region composition and orientation analysis. The CO2 corrosion results show that the corrosion resistance of the base material is the best, followed by heataffected zone and the welded seam is the worst. The grooving corrosion occurred in the welded seam, and the grooving corrosion susceptibility of welded seam is relativity high. The dominated reason for the grooving corrosion of the electric resistance welded joint is the notable inclusions consisting of MnS as the main content in the welded seam. The proportion of high-angle grain boundaries in the welding zone is higher than that of base metal and the heat affected zone, which plays an important role in the corrosion behavior of the welded seam.
文摘目的 探究驱动蛋白家族成员2A(kinesin family member 2A,KIF2A)对肝癌细胞5-FU耐药的作用及其作用机制。方法 采用浓度梯度递增联合大剂量间断冲击的方法诱导肝癌细胞BEL7402对5-FU耐药,以构建耐药株BEL7402/5-FU。采用慢病毒技术构建KIF2A沉默的BEL7402/5-FU细胞。用Notch1/Hes1信号通路激动剂丙戊酸(valproic acid,VPA)对KIF2A沉默的BEL7402/5-FU细胞进行干预。用CCK-8实验、蛋白印迹法、免疫荧光、流式细胞术检测细胞活性、细胞凋亡率、KIF2A、cleaved-caspase-3、Notch1和Hes1的蛋白表达。结果 BEL7402/5-FU细胞具有强5-FU耐药性,其IC_(50)为344.2μmol/L,是BEL7402细胞的92倍(IC_(50)=3.730μmol/L)。与BEL7402细胞比较,BEL7402/5-FU细胞中KIF2A蛋白表达明显增加(P<0.001);与si-NC组比较,si-KIF2A组BEL7402/5-FU细胞活性明显下降(P<0.001)、凋亡率和cleaved-caspase-3蛋白表达明显增加(P<0.001),另外Notch1和Hes1蛋白表达明显减少(P<0.001);与si-NC+5-FU组比较,si-KIF2A+5-FU组BEL7402/5-FU细胞活性显著下降(P<0.001)、凋亡率显著增加(P<0.001);与si-KIF2A+5-FU组比较,si-KIF2A+5-FU+VPA组BEL7402/5-FU细胞活性明显提高(P<0.001)、凋亡率显著降低(P<0.001)、Notch1和Hes1蛋白表达量显著增加(P<0.001)。结论 KIF2A的沉默通过抑制Notch1/Hes1信号通路活性减弱BEL7402/5-FU细胞对5-FU的化疗耐药性。
基金Project(51474238)supported by the National Natural Science Foundation of China
文摘A comparative study on the corrosion resistance of 17Ni/（NiFe2O4-10NiO） cermet inert anode prepared in differentsintering atmospheres was conducted in Na3AlF6-Al2O3 melt. The results indicate that the corrosion rates of NiFe2O4-based cermetanodes prepared in the vacuum and the atmosphere with oxygen content of 2×10^-3 （volume fraction） are 6.46 and 2.71 cm/a,respectively. Though there is a transition layer with lots of holes or pores, a densified layer is formed on the surface of anode due tosome reactions producing aluminates. For the anode prepared in the atmosphere with oxygen content of 2×10^-3, the thickness of thedensification layer （about 50 μm） is thicker than that （about 30 μm） formed on the surface of anode prepared in the vacuum. Thecontents of NiO and Fe（II） in NiFe2xO4-y-z increase with the decrease of oxygen content in sintering atmosphere, which reduces thecorrosion resistance of the material.
文摘Polyamides containing thieno[2,3-b]thiophene moiety were prepared via a simple polycondensation reaction of the diaminothieno[2,3-b]thiophene monomer la with different kinds of diacid chlorides （including oxalyl, adipoyl, sebacoyl, isophthaloyl, terephthaloyl, 4,4＇-azodibenzoyl, 3,3＇-azodibenzoyl, p-phenylene diacryloyl） in the presence of LiC1 and NMP as a solvent through lowtemperature solution polycondensation. The chemical structures of model compound and synthesized polyamides were confirmed by FTIR, nuclear magnetic resonance spectroscopy （including 1 H-NMR and 13 C-NMR） and elemental analysis. In addition, the thermal stability, crystallinity structure and surface morphology of synthesized polyamides were characterized via thermogravametric analysis （TGA）, wide-angle X-ray diffraction analysis （WAXD） and scanning electron microscopy （SEM）. Also, the corrosion inhibition behavior of selected examples ofpolyamides was investigated; the inhibitive effect of the investigated polymers for carbon steel in 1.0 mol＇L-1 HCI was studied using potentiodynamic polarization （PDP） and electrochemical impedance spectroscopy （EIS） methods. PDP results displayed that the polyamides containing thieno[2,3-b]thiophene moiety can be as mixed-type inhibitors. The inhibition efficiency （P, %） was found to be in the range from 67.13% to 96.01%. There is an increase in P by the synthesized polymers in comparison to the starting monomer. The adsorption of these polymers was found to obey Langmuir adsorption isotherm.
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 (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.
基金supported by the National Natural Science Fund of China (Nos.51622106 and 5167010950)the National Key Basic Research and Development Plan of China (No.2014CB643303)the International S&T Cooperation Program of China (ISTCP) (No.2014DFR50560)
文摘The corrosion behavior of 2 A02 Al alloy under simulated marine atmospheric environment has been studied using mass-gain, scanning electron microscope/energy dispersive spectroscopy(SEM/EDS), laser scanning confocal microscopy, X-ray diffraction spectroscopy and localized electrochemical methods. The results demonstrate that the relationship between the corrosion induced mass-gain and the corrosion time is in accordance with the power rule. The mass-gain increases gradually during the corrosion time,while the corrosion rate decreases. With ongoing of the corrosion, corrosion products film changed from a porous to a compact structure. The various spectroscopic data show that the corrosion products films composed mainly of Al(OH)_3, Al_2O_3 and AlCl_3. The electrochemical corrosion behavior of the 2 A02 Al alloy was studied by electrochemical impedance spectroscopy(EIS).
基金supported by the Postdoctoral Fellowship Program of CPSF(No.GZC20231545)the China Postdoctoral Science Foundation(Nos.2024T170557 and 2023M742224)+6 种基金the Shanghai Post-doctoral Excellence Program(No.2023440)the National Natural Science Foundation of China(Nos.52127801,52401101,and 22205012)the Shenzhen Basic Research Project(Nos.JCYJ20210324120001003,JCYJ20200109144608205)the Guangdong Basic and Applied Basic Research Foundation(Nos.2020A1515011301 and 2021A1515012246)the IER Foundation(Nos.IERF202201 andIERF202202),the City University of Hong Kong Donation Research(No.DON-RMG 9229021)the Hong Kong PDFS-RGC Postdoctoral Fellowship Scheme(Nos.PDFS2122–1S08 and CityU 9061014)the Hong Kong HMRF(Health and Medical Research Fund)(Nos.2120972 and CityU 9211320).
文摘The poor corrosion resistance of magnesium(Mg)and its alloys limits their application in various fields.Micro arc oxidation(MAO)coatings can improve the corrosion resistance,but the pore defects and low surface hardness make them susceptible to wear and accelerated corrosion during usage.In this study,a ZrO_(2)nanoparticles doped-MAO coating is prepared on the ZK61 Mg alloy by utilizing an MgF_(2)passivation layer to prevent ablation.The ZrO_(2)nanoparticles re-melt and precipitate due to local discharging,which produces evenly dispersed nanocrystals in the MAO coating.As a result,the hardness of the MAO coating with the appropriate ZrO_(2)concentration increases by over 10 times,while the wear rate decreases and corrosion resistance increases.With increasing ZrO_(2)concentrations,the corrosion potentials increase from−1.528 V of the bare ZK61 Mg alloy to−1.184 V,the corrosion current density decreases from 1.065×10^(–4)A cm^(–2)to 3.960×10^(–8)A cm^(–2),and the charge transfer resistance increases from 3.41×10^(2)Ωcm^(2)to 6.782×10^(5)Ωcm^(2).Immersion tests conducted in a salt solution for 28 d reveal minimal corrosion in contrast to severe corrosion on the untreated ZK61 Mg alloy.ZrO_(2)nanoparticles improve the corrosion resistance of MAO coatings by sealing pores and secondary strengthening of the corrosion product layer.
基金This work was financially supported by the National Natural Science Foundation of China (Project No. 59899144). The authors are grateful to Ms Wang for English diction.
文摘The regularities of atmospheric corrosion of A3 steel deposited with different amount of NaCl exposed to the air containing 1ppm SO2 at 80%RH and 25℃ were studied in laboratory. NaCl can accelerate the corrosion of A3 steel obviously under such condition. The relationship between the weight loss of A3 steel and the amount of NaCl deposition can be well described by using a quadratic function. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy and electron dispersion X-ray analysis (SEM/EDAX) were used to characterize the corrosion products. In the absence of NaCl, FeSO4 · xH2O is the dominant corrosion products, while Fe3O4, FeSO4·H2O, β-FeOOH and γ-FeOOH dominate in the presence of NaCl.
基金Item Sponsored by National High-Tech Research and Development Program(863Program)of China(2012AA03A508)
文摘Four kinds of P110 grade tube steels containing different chromium contents were designed to probe the in- fluence of Cr on the properties of tube steel. The microstrueture, mechanical properties and corrosion behavior of the four kinds of P110 grade tube steels were studied deeply and thoroughly. The analysis of the mechanical properties indicated that tensile strength and yield strength of the steel plates were improved, while transverse and longitudinal impact energy and elongation first increased and then decreased when Cr content rose. The impact energy and elonga tion reached the peak when Cr content was 1 ~. Cr precipitates were found only in 3 ~ Cr steel, with （Nb, Ti）（C, N） or Nb（C,N） as the core of precipitation and then grew up. The corrosion experiments demonstrated that the scales on the four steels had a two layer structure under the corrosion of CO2 and H2 S. The outer layer was mainly com- posed of FeS or FeS1 x and the inner layer consisted of FeCOa and Cr compounds. Cr was rich in the inner layer and the Cr content of the inner layer increased with the Cr content in matrix. The enriched Cr enhanced the compactness of the scales, further hindering the diffusion of ions from liquid to the surface of steel, thus reducing corrosion rate.
基金Item Sponsored by National Natural Science Foundation of China (50231020) , National Basic Research Programof China(G1999065004) ,2001'Key Laboratory Opening Fund of Corrosion and Protection of Tabular Goods Research Center of ChinaNational Petroleum Corporation (ZYT-01070)
文摘To investigate the correlation between structure characteristics and wear resistance of CO2 corrosion product scales at high temperature and high pressure, an autoclave was used to prepare CO2 corrosion product scales on N80 steel in carbon dioxide corrosion environment. The correlation between wear resistance of the scales and many other factors, such as temperature, pressure, morphology, structure, velocity of fluid medium, sand grain size, and so on, was comparatively analyzed by a self assembled wear device, and the scale morphologies before or after being worn were observed by scanning electron microscope （SEM）. And then the surface grain size and thickness of scale were measured. The results showed that the cross-section of the corrosion scale was of a double-layer structure, the outer layer of which was composed of regular crystals, whereas the inner layer was a thin scale of fine grains. The outer grain size and thickness of scale varied with temperature, and the initial wear loss was consistent with the surface grain size; at the same time, the total wear loss corresponded to the thickness of scale. Compared to wear resist- ance in different depths of the scale, it was found that the structure of scale was a double-layer structure in cross-section, and the wear resistance of inner layer was better than that of the outer layer; the closer the scale to the matrix, the greater was the wear resistance of scale; and the larger the size or the higher the rotary speed of solid grain in multiphase flowing medium, the more was the wear loss of scale.
基金TheResearchProjectofTubularGoodsRe searchCenterofChinaNationalPetroleumCorporation (No .2 3 5 2 4)andtheResearchProjectofHenanUniversityofScienceandTechnology (No .2 0 0 10 1)
文摘Based on an analysis of the existing models of CO 2 corrosion in literatures and the autoclave simulative experiments, a predictive model of corrosion rate (r corr) in CO 2/H 2S corrosion for oil tubes has been established, in which r corr is expressed as a function of pH, temperature (T), pressure of CO 2 (P CO 2) and pressure of H 2S (P H 2S). The model has been verified by experimental data obtained on N80 steel. The improved features of the predictive model include the following aspects: (1) The influence of temperature on the protectiveness of corrosion film is taken into consideration for establishment of predictive model of the r corr in CO 2/H 2S corrosion. The Equations of scale temperature and scale factor are put forward, and they fit the experimental result very well. (2) The linear relationship still exists between ln r corr and ln P CO 2 in CO 2/H 2S corrosion (as same as that in CO 2 corrosion). Therefore, a correction factor as a function of P H 2S has been introduced into the predictive model in CO 2/H 2S corrosion. (3) The model is compatible with the main existing models.
基金Funded by Key National Science&Technology Specific Projects(No.2008ZX05017-002)
文摘The corrosion behavior of C100 steel in simulated environments with high H2S and CO2 content was studied through high-temperature and high-pressure autoclave, and the HaS stress corrosion cracking （SSC） resistance of C100 steel was evaluated by SSC tests. Scanning electron microscopy （SEM）, transmission electron microscope （TEM） and X-ray diffraction （XRD） technique were employed to characterize the corrosion products and the metal matrix. The results indicate that all of the corrosion products in this investigation are mainly composed of different types of iron sulfide such as Fe0.95S, FeS0.9, F0.985S, Fe7S8 and FeS, and the absence of iron carbonate in the corrosion scales suggests that the corrosion process is governed by H2S corrosion. The corrosion rate decreases in the initial stage and then increases with the enhancement of the temperature. There exists a minimum corrosion rate at about 110 ℃. Under the partial pressure of H2S lower than 9 MPa, the corrosion rate decreases with the increase of P112S While over 9 MPa, a higher P112S will result in a faster corrosion process. When the applied stress is 72%, 80% and 85% of actual yield strength （AYS）, all tested specimens show no crack, which reveals a superior SSC resistance.
