等离子体源渗氮2Cr13马氏体不锈钢的耐磨与耐腐蚀性能

Wear and Corrosion Resistance of Plasma Source Nitrided 2Cr13 Martensitic Stainless Steel

对2Cr13马氏体不锈钢进行450℃×6h的等离子体源渗氮处理,对比研究了渗氮前后该钢表层的显微组织、物相组成以及耐磨和耐腐蚀性能。结果表明:渗氮后不锈钢表层形成了厚约18μm,由αN、ε-Fe3N和γ′-Fe4N组成的化合物层,以及组织明显细化的氮扩散层,氮原子渗透深度达20μm;渗氮后不锈钢的表面硬度高达1 350HV,摩擦因数低于未渗氮处理的,磨损机制由未渗氮处理的黏着磨损转变为氧化磨损,耐磨性能明显高于未渗氮处理的;在质量分数3.5%NaCl溶液中,未渗氮不锈钢的阳极极化曲线仅呈现活化溶解特征,渗氮后则呈现活化溶解、自钝化和点蚀击穿特征,且自腐蚀电位提高至-104mV,耐腐蚀性能显著提高。

2 Cr13 martensitic stainless steel was treated by plasma source nitriding at 450℃for 6 h,and then the microstructure,phase composition,wear resistance and corrosion resistance of the steel surface layer before and after nitriding were studied and compared.The results show that after nitriding,an about 18μm thick compound layer composed ofαN,ε-Fe3 N andγ′-Fe4 N and a nitrogen diffusion layer with obvious refined structure were formed on surface of the stainless steel.The nitrogen atom penetration depth reached 20μm.The surface hardness of the nitrided stainless steel was up to 1 350 HV and the friction factor was lower than that before nitriding.The wear mechanism changed from adhesive wear before nitriding to oxidative wear after nitriding.The wear resistance after nitriding was obviously higher than that before nitriding.In 3.5 wt%NaCl solution,the anodic polarization curve of the stainless steel before nitriding only showed a feature of activation dissolution while after nitriding showed features of activation dissolution,self-passivation and pitting breakdown.After nitriding,the free-corrosion potential increased to-104 mV and the corrosion resistance was improved significantly.