激光熔覆-离子渗氮复合改性层的组织和耐磨耐蚀性研究  

Study on microstructures,wear resistance and corrosion resistance of laser cladding-ion nitriding composite modified layer

作　　者：蒋淑英 许红明 蔡畅 李浩楠 JIANG Shuying;XU Hongming;CAI Chang;LI Haonan(College of Materials Science and Engineering in China University of Petroleum (East China), Qingdao 266580, China)

机构地区：[1]中国石油大学(华东)材料科学与工程学院,山东青岛266580

出　　处：《中国石油大学学报（自然科学版）》2022年第1期163-170,共8页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：山东省自然科学基金面上项目(ZR2020ME013)。

摘　　要：为解决常规渗氮技术渗氮速度慢渗层浅、截面硬度梯度大、脆性高和耐磨耐蚀性偏低的问题,在N80钢表面制备Cr-Ni-Ti-La激光熔覆-离子渗氮复合改性层。采用光学显微镜、X射线衍射仪、硬度计、摩擦磨损试验机及电化学工作站对激光熔覆-离子渗氮复合改性试样和未熔覆直接渗氮试样的组织和耐磨耐蚀性进行对比研究。结果表明渗氮前后的熔覆层组织结构基本相同,硬度远高于N80钢基体,增强了对渗氮层的强度支撑和对试样截面硬度梯度的改善。熔覆层的存在促进了离子渗氮,显著增加了渗氮速度和渗氮层厚度。与未熔覆直接渗氮试样相比,激光熔覆-离子渗氮复合改性试样表面硬度进一步增大,摩擦系数、磨痕深度和磨损失重显著降低,耐磨性提高。在盐溶液中,其自腐蚀电流密度约为未熔覆直接渗氮试样的二分之一;在酸溶液中,二者的自腐蚀电流密度差约为100倍;激光熔覆-离子渗氮复合改性试样的耐蚀性显著增加。In order to solve the problems of low nitriding speed,shallow nitriding layer,large cross-section hardness gradient and high brittleness of conventional nitriding technology,and further improving the wear and corrosion resistance,the Cr-Ni-Ti-La laser cladding-ion nitriding composite modified layer was prepared on the surface of N80 steel substrate.The microstructures,wear resistance and corrosion resistance on the laser cladding-ion nitriding composite modified sample and the nitrided sample without cladding were studied by the optical microscope,X-ray diffractometer,hardness tester,friction and wear tester and electrochemical workstation for comparison.The results show that the microstructures of the cladding layer before and after nitriding are basically the same and the hardness is much higher than that of the N80 steel substrate,and this treatment enhances the strength support of the nitriding layer and improves the hardness gradient of the sample section.The presence of the cladding layer promotes the ionic nitriding and significantly increases the nitriding speed and thickness of the nitriding layer.Compared with the nitrided sample without cladding,the surface hardness of the composite modified sample is further increased,the friction coefficient,wear scar depth and wear weight loss are significantly reduced,and the wear resistance is improved.In salt solution,the self-corrosion current density is about half of that of the nitrided sample without cladding;in acid solution,the difference of self-corrosion current density between the two cases is about 100 times.The corrosion resistance of the laser cladding-ion nitriding composite modified sample is significantly increased.

关 键 词：激光熔覆 离子渗氮 稀土催渗 耐磨性 耐蚀性 

分 类 号：TG156.8[金属学及工艺—热处理]