In this article,NiCr coatings with chromium content of 13%,27%and 41%were prepared by arc spraying.They were exposed in molten salts(NaCl-Na_(2)SO_(4))at 800℃for 200 hours.The effect of chromium content on the hot co...In this article,NiCr coatings with chromium content of 13%,27%and 41%were prepared by arc spraying.They were exposed in molten salts(NaCl-Na_(2)SO_(4))at 800℃for 200 hours.The effect of chromium content on the hot corrosion behavior of the coatings was in-vestigated.X-ray diffraction(XRD)and scanning electron microscope with energy dispersion spectrum(SEM-EDS)were used to analyze the phase compositions,morphologies and chemical compositions of the coatings.The results show that NiCr13 coating exhibited the worst hot corrosion resistance due to the low chromium content,which resulted in NiO being the major reaction product.It should be noted that the hot corrosion resistance of NiCr27 coating was better than that of NiCr41 coating.The basic fluxing of Cr_(2)O_(3) lowered its protection during the hot corrosion process and led to the formation of porous Cr_(2)O_(3) on the NiCr41 coating.The molten salts accelerated the oxidation reac-tion resulting in thicker and porous oxide scales formed on the surfaces of coatings.展开更多
采用熔化极气体保护焊技术(gas metal arc welding,GMAW)制备了Fe-Cr-C-Nb堆焊合金,对合金在不同法向载荷(70～190N)下进行干砂/橡胶轮松散三体磨粒磨损实验。通过X射线衍射分析、扫描电子显微镜观察、能谱分析、磨损失重测试、体视显...采用熔化极气体保护焊技术(gas metal arc welding,GMAW)制备了Fe-Cr-C-Nb堆焊合金,对合金在不同法向载荷(70～190N)下进行干砂/橡胶轮松散三体磨粒磨损实验。通过X射线衍射分析、扫描电子显微镜观察、能谱分析、磨损失重测试、体视显微镜观察、激光扫描共焦显微镜观察和维氏硬度测量等手段表征了合金显微组织与磨痕特征,研究了合金在不同法向载荷作用下磨损行为的变化。结果表明:堆焊合金显微组织主要由初生奥氏体基体、网状共晶组织及分布于基体上的NbC硬质相组成;合金磨损损失、磨痕深度随法向载荷增大而增大,磨损机制主要为奥氏体基体的微切削及NbC、M_7C_3的脆性剥落;法向载荷的提高加剧了磨痕亚表面的加工硬化,从而提高了奥氏体基体耐磨性,这导致磨损损失及磨痕深度增长幅度缓慢。展开更多
基金supported by Corporate Talent Fund Program of Zhengzhou Research Institute of Mechanical Engineering Co.,Ltd.(No.201SJ2023013)the Faculty of Materials and Manufacturing,Beijing University of Technology.
文摘In this article,NiCr coatings with chromium content of 13%,27%and 41%were prepared by arc spraying.They were exposed in molten salts(NaCl-Na_(2)SO_(4))at 800℃for 200 hours.The effect of chromium content on the hot corrosion behavior of the coatings was in-vestigated.X-ray diffraction(XRD)and scanning electron microscope with energy dispersion spectrum(SEM-EDS)were used to analyze the phase compositions,morphologies and chemical compositions of the coatings.The results show that NiCr13 coating exhibited the worst hot corrosion resistance due to the low chromium content,which resulted in NiO being the major reaction product.It should be noted that the hot corrosion resistance of NiCr27 coating was better than that of NiCr41 coating.The basic fluxing of Cr_(2)O_(3) lowered its protection during the hot corrosion process and led to the formation of porous Cr_(2)O_(3) on the NiCr41 coating.The molten salts accelerated the oxidation reac-tion resulting in thicker and porous oxide scales formed on the surfaces of coatings.
文摘采用熔化极气体保护焊技术(gas metal arc welding,GMAW)制备了Fe-Cr-C-Nb堆焊合金,对合金在不同法向载荷(70～190N)下进行干砂/橡胶轮松散三体磨粒磨损实验。通过X射线衍射分析、扫描电子显微镜观察、能谱分析、磨损失重测试、体视显微镜观察、激光扫描共焦显微镜观察和维氏硬度测量等手段表征了合金显微组织与磨痕特征,研究了合金在不同法向载荷作用下磨损行为的变化。结果表明:堆焊合金显微组织主要由初生奥氏体基体、网状共晶组织及分布于基体上的NbC硬质相组成;合金磨损损失、磨痕深度随法向载荷增大而增大,磨损机制主要为奥氏体基体的微切削及NbC、M_7C_3的脆性剥落;法向载荷的提高加剧了磨痕亚表面的加工硬化,从而提高了奥氏体基体耐磨性,这导致磨损损失及磨痕深度增长幅度缓慢。
