炮钢表面等离子堆焊Fe基涂层及其烧蚀行为研究

在炮钢表面利用等离子堆焊分别制备了A、B两种Fe基耐烧蚀涂层，利用X射线衍射仪、扫描电子显微镜、能谱仪分析了涂层的微观组织和元素含量，利用维氏硬度计测量了涂层的硬度，利用高速热流发生装置模拟了火炮发射时的高温高压环境，对涂层进行了烧蚀试验.结果表明，两种Fe基涂层均与基体形成了良好的冶金结合，涂层A的组织主要由Fe-Cr固溶体、Fe₃Ni₂及（Cr，Fe）₇C₃组成，涂层B的组织主要由Fe-Cr固溶体、Cr₃Ni₂、Fe_0.64Ni_0.36及Fe₇C₃组成.经过40次高速热流烧蚀后，电镜下观察涂层A发生的烧蚀行为，其烧蚀过程是由"晶间烧蚀"扩展到"沿晶烧蚀"最后到"全晶烧蚀"，电镜下观察涂层B未发生明显的烧蚀行为，但是在热冷循环过程中产生了"穿晶"裂纹，与炮钢相比，两种涂层的耐烧蚀性能均有明显提高. 

Fe-Based Coatings on Gun Steel Surface Deposited by PTA and Their Erosion Behavior

Fe-based erosion resistant coatings A and B were prepared by plasma surfacing on the surface of gun steel.The microstructure and elements of the coatings were analyzed by X-ray diffraction,scanning electron microscopy and energy dispersive spectrometer.The hardness of the coating was measured by Vickers hardness tester,and the erosion resistance of the coating was tested by high speed heat flow generating device.The results show that both Fe-based coatings have good metallurgical bonding with the substrate.Coating A is com posed of Fe3Ni2,(Cr,Fe) 7C3 and Fe-Cr solid solution.Coating B is composed of Cr3Ni2,Fe0.64Ni0.36,Fe7C3,Fe-Cr solid solution.After 40 tests of high-speed heat flow's erosion,the erosion behavior of the coatings was observed under scanning electron microscopy.Results show that,the erosion process of Coating A is extended from "intergranular erosion",to "crystallization erosion",then to "full crystal erosion".Coating B shows no obvious erosion behavior under scanning electron microscopy,but has produced transcrystalline cracks in the hot and cold cycle process.The two coatings have significantly enhanced the erosion resistance compared with the gun steel.