渗氮时间对38CrMoAl钢液相等离子体渗氮层组织及性能影响

Effect of plasma electrolytic nitriding time on microstructure and properties of 38CrMoAl steel

应用液相等离子体电解渗氮技术,在氨水电解液体系下,探究渗氮时间对38CrMoAl钢液相等离子体渗氮组织与性能影响。采用OM、SEM、XRD对渗氮层的微观组织结构、相组成进行了观察和分析,采用Parstat2273电化学工作站测试了渗层的耐蚀性能,并对渗层显微硬度和耐磨性进行了测试。结果表明:随着渗氮时间的延长,渗氮层中白亮层呈先增加后降低的趋势,扩散层不断增加;试样表面"火山凸起"微区落差和层絮状结构逐渐增大,孔洞分布均匀度降低且孔径逐渐增大,表面粗糙度明显提高;渗氮层最大硬度值逐渐增大,耐磨性能较之未处理试样有显著提升,最大磨损失重量随着处理时间延长而降低;经2、5、10min液相等离子体电解渗氮处理的试样表现出的耐蚀性要高于未经处理试样,其中t=10 min时,耐蚀性最好;经15 min液相等离子体电解渗氮处理的试样表现出的耐蚀性要低于未经处理试样。

Effect of plasma electrolytic nitriding time on microstructure and properties of 38 CrMoAl steel was investigated in an aqueous solution containing ammonia and KCl.The microstructure and phase composition of the nitrided layer were examined using optical microscope(OM),scanning electron microscopy(SEM) and X-ray diffraction(XRD).The corrosion resistance of the nitrided layer was detected by Parstat2273 electrochemical workstation.The hardness and wear resistance of the nitrided layer were tested.The results show that with the increase of nitriding time,the white layer thickness of the nitrided layer first increases and then decreases; the thickness of diffusion layer,'bulge volcano'micro-area gap and flocculent structure,the pore size,the roughness and maximum hardness are increased,and the evenness of the pore distribution and the maximum wear mass loss are decreased.The corrosion resistance of the specimens treated for 2,5 and 10 min by plasma electrolytic nitriding is higher than that of the specimen untreated.However,the corrosion resistance of the specimen treated for 15 min is lower than that of the untreated specimen.