脉冲单电源等离子表面渗铬层组织分析

Microstructure Analysis on Plasma Chromizing Layer Formed by Single Pulse Power Supply

利用脉冲单电源在碳钢表面进行等离子渗铬,对850℃和1100℃条件下得到的渗层组织进行了分析。结果表明:850℃所得渗层和基体之间有两条明显的分界线,说明在渗铬过程中,发生了两次反应扩散相变;在1100℃条件下,渗层和基体之间有一条明显的分界线,说明在渗铬过程中,发生了一次反应扩散相变;两种工艺得到的渗层厚度分别为170μm和140μm,表面的含铬量分别为9.25%和40%(质量分数),渗铬层主要相组成为Fe-Cr固溶体;在1100℃条件下,渗层是由沉积层+扩散层组成,沉积层的形成阻碍了扩散层的进一步加厚。

The plasma chromizing process was realized by single pulse power supply on carbon steel surface.The microstructure of alloying layer at 850 ℃ and 1100 ℃ was investigated.The results show that,treated at 850 ℃,two dividing lines forms between the diffusion layer and the substrate,which means that two reaction-diffusion phase transformations happens;at 1100 ℃,one dividing line lies between the diffusion layer and the substrate,which suggests that in this condition one reaction-diffusion phase transformation happens.The depth of alloying layer is 170 μm and 140 μm,respectively.The surface chromium contents are 9.25% and 40%（wt%）.The main phase of the alloying layer is Fe-Cr solid solution.At 1100 ℃,the alloying layer is composed of deposition layer and diffusion layer.The formation of deposition layer blocks the growth of diffusion layer.