A Cr/CoNiCrAlTaY bilayer coating was prepared on the Ti-45Al-8.5Nb alloy by plasma surface metallurgy technique.The as-prepared coating with a grain size of~2μm exhibited a dense microstructure and strong adhesion du...A Cr/CoNiCrAlTaY bilayer coating was prepared on the Ti-45Al-8.5Nb alloy by plasma surface metallurgy technique.The as-prepared coating with a grain size of~2μm exhibited a dense microstructure and strong adhesion due to metallurgical bonding,consisting of outermost Cr layer and CoNiCrAlTaY transition layer.The typical power-law relationship between mass gain and time was obtained for the coated specimens with a rate exponent of 3.18 following oxidation at 1173 K.The top Cr_(2)O_(3)film and spinel oxides(i.e.,NiCr_(2)O_(4)and CoCr_(2)O_(4))exhibited a protective effect with a low oxidation reaction rate.Interfacial analysis identified Ta precipitates(Cr_(2)Ta and TaAl_(3))and Ta oxides(Ta_(2)O_(5)and Ta_(2)O_(3)),which played an essential role in retarding rapid diffusion and enhancing adhesion and oxidation resistance.展开更多
A novel Fe–Cr–Mo amorphous coating,a high-temperature corrosion-resistant material for water wall protection of power plant ultra-supercritical boilers,has been prepared via arc spraying.A systematic study was condu...A novel Fe–Cr–Mo amorphous coating,a high-temperature corrosion-resistant material for water wall protection of power plant ultra-supercritical boilers,has been prepared via arc spraying.A systematic study was conducted to evaluate the high-temperature corrosion behavior of this coating,and its resistance to corrosion at high temperatures was scientifically assessed.The results indicate that the thickness of Fe–Cr–Mo amorphous coating is approximately 350μm,exhibiting typical amorphous characteristics as confirmed by X-ray diffraction and transmission electron microscope characterization.During each stage of the 750℃corrosion test,the oxygen content of the amorphous coating was significantly lower than that of the contrast coating(PS45 alloy coating),indicating a superior corrosion protection effect at high temperature.After 100 h of continuous testing,the corrosion mass gain of the amorphous coating was only 28.62%that of PS45 coating and 3.89%that of T12 steel substrate,indicating significantly depressed high-temperature corrosion kinetics.The excellent high-temperature corrosion resistance of Fe–Cr–Mo amorphous coating is primarily attributed to the stable Fe/Cr oxide film generated by the metastable state of the amorphous state,which serves as an excellent barrier.Furthermore,under the influence of heat in a high-temperature environment,the amorphous structure gradually transforms into a nanocrystalline structure.In contrast,the oxide film of the amorphous/nanocrystalline coating has low thermal stress,leading to better adhesion with the coating and resistance to cracking and peeling,thus providing excellent sustained protection.展开更多
The interdiffusion coefficients in Al_(0.2)CoCrFeNi,CoCrCu_(0.2)FeNi,and CoCrFeMn_(0.2)Ni high-entropy alloys were efficiently determined by combining diffusion couple experiments and high-throughput determination of ...The interdiffusion coefficients in Al_(0.2)CoCrFeNi,CoCrCu_(0.2)FeNi,and CoCrFeMn_(0.2)Ni high-entropy alloys were efficiently determined by combining diffusion couple experiments and high-throughput determination of interdiffusion coefficients(HitDIC)software at 1273−1373 K.The results show that the addition of Al,Cu,and Mn to CoCrFeNi high-entropy alloys promotes the diffusion of Co,Cr,and Fe atoms.The comparison of tracer diffusion coefficients indicates that there is no sluggish diffusion in tracer diffusion on the thermodynamic temperature scale for the present Al_(0.2)CoCrFeNi,CoCrCu_(0.2)FeNi,and CoCrFeMn_(0.2)Ni high-entropy alloys.The linear relationship between diffusion entropy and activation energy reveals that the diffusion process of atoms is unaffected by an increase in the number of components as long as the crystal structure remains unchanged.展开更多
基金financial supports from Shanxi Provincial Natural Science Foundation,China(No.20210302123162)Shanxi Scholarship Council of China(No.2024-057)+2 种基金State Key Laboratory of Advanced Metal Materials,China(No.2019-ZD02)Science and Technology Achievement Transformation and Cultivation Project of Shanxi,China(No.2020CG011)Shanxi“1331 Project”Quality Improvement and Efficiency Project,China。
文摘A Cr/CoNiCrAlTaY bilayer coating was prepared on the Ti-45Al-8.5Nb alloy by plasma surface metallurgy technique.The as-prepared coating with a grain size of~2μm exhibited a dense microstructure and strong adhesion due to metallurgical bonding,consisting of outermost Cr layer and CoNiCrAlTaY transition layer.The typical power-law relationship between mass gain and time was obtained for the coated specimens with a rate exponent of 3.18 following oxidation at 1173 K.The top Cr_(2)O_(3)film and spinel oxides(i.e.,NiCr_(2)O_(4)and CoCr_(2)O_(4))exhibited a protective effect with a low oxidation reaction rate.Interfacial analysis identified Ta precipitates(Cr_(2)Ta and TaAl_(3))and Ta oxides(Ta_(2)O_(5)and Ta_(2)O_(3)),which played an essential role in retarding rapid diffusion and enhancing adhesion and oxidation resistance.
基金The authors would like to acknowledge the financial support from China Power International Holding Ltd.(ZGDL-KJ-2022-024)Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX23_0179).
文摘A novel Fe–Cr–Mo amorphous coating,a high-temperature corrosion-resistant material for water wall protection of power plant ultra-supercritical boilers,has been prepared via arc spraying.A systematic study was conducted to evaluate the high-temperature corrosion behavior of this coating,and its resistance to corrosion at high temperatures was scientifically assessed.The results indicate that the thickness of Fe–Cr–Mo amorphous coating is approximately 350μm,exhibiting typical amorphous characteristics as confirmed by X-ray diffraction and transmission electron microscope characterization.During each stage of the 750℃corrosion test,the oxygen content of the amorphous coating was significantly lower than that of the contrast coating(PS45 alloy coating),indicating a superior corrosion protection effect at high temperature.After 100 h of continuous testing,the corrosion mass gain of the amorphous coating was only 28.62%that of PS45 coating and 3.89%that of T12 steel substrate,indicating significantly depressed high-temperature corrosion kinetics.The excellent high-temperature corrosion resistance of Fe–Cr–Mo amorphous coating is primarily attributed to the stable Fe/Cr oxide film generated by the metastable state of the amorphous state,which serves as an excellent barrier.Furthermore,under the influence of heat in a high-temperature environment,the amorphous structure gradually transforms into a nanocrystalline structure.In contrast,the oxide film of the amorphous/nanocrystalline coating has low thermal stress,leading to better adhesion with the coating and resistance to cracking and peeling,thus providing excellent sustained protection.
基金supported by the National Natural Science Foundation of China(No.52374372)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.23KJB430042)+3 种基金the Jiangsu Province Large Scientific Instruments Open Sharing Autonomous Research Filing Project,China(No.TC2023A037)the Yangzhou City−Yangzhou University Cooperation Foundation,China(No.YZ2022183)High-end Talent Support Program of Yangzhou University,China,Qinglan Project of Yangzhou University,ChinaLvyangjinfeng Talent program of Yangzhou,China.
文摘The interdiffusion coefficients in Al_(0.2)CoCrFeNi,CoCrCu_(0.2)FeNi,and CoCrFeMn_(0.2)Ni high-entropy alloys were efficiently determined by combining diffusion couple experiments and high-throughput determination of interdiffusion coefficients(HitDIC)software at 1273−1373 K.The results show that the addition of Al,Cu,and Mn to CoCrFeNi high-entropy alloys promotes the diffusion of Co,Cr,and Fe atoms.The comparison of tracer diffusion coefficients indicates that there is no sluggish diffusion in tracer diffusion on the thermodynamic temperature scale for the present Al_(0.2)CoCrFeNi,CoCrCu_(0.2)FeNi,and CoCrFeMn_(0.2)Ni high-entropy alloys.The linear relationship between diffusion entropy and activation energy reveals that the diffusion process of atoms is unaffected by an increase in the number of components as long as the crystal structure remains unchanged.
