45钢表面激光熔覆Ni_(20)合金粉末的组织及耐腐蚀性能研究  

Research on Microstructure and Corrosion Properties of Laser Cladding Ni_(20)-based Alloy of 45 Steel Surface

作　　者：李涌泉[1] 宋文学[1] 余斌高[1] 

机构地区：[1]西安航空技术高等专科学校航空工程系,陕西西安710077

出　　处：《新技术新工艺》2012年第3期74-76,共3页New Technology & New Process

摘　　要：利用激光熔覆技术,在45钢表面制备了Ni20合金粉末熔覆层,通过SEM、XRD等方法分析表明研究涂层相及组织。利用CHI660B电化学测试系统,测试膜层及基体的开路电位及极化曲线,采用SY/Q-750型盐雾腐蚀试验箱,对熔覆层的耐腐蚀性能进行研究。结果表明:熔覆层与基体形成良好的冶金结合;熔覆层组织具有定向凝固特征且晶粒生长方向垂直于界面;熔覆层主要由CrNiFeC,Fe3Ni2,Ni3Cr2等相组成;Ni20合金合金粉末激光熔覆层在3.5%NaCl盐雾中的腐蚀为局部点蚀,45钢为均匀腐蚀,熔覆层腐蚀速率仅为45钢的一半;电化学测试表明熔覆层的自腐蚀电位较45钢正移,具有更小腐蚀电流密度。Metallurgical binding and compact alloy layers were prepared by laser cladding technology with Niz0-based al- loy powders on 45 steel surface. The microstructure and phase of the laser cladding were analyzed by using SEM,XRD and so on. The open circuit potential and polarization curve of matrix and laser cladding were tested by CHI660B eleetrochemis-try test,and the corrosion properties of laser cladding was researched by SY/Q-750 corrosion test chamber. The results showed that an excellent metallurgical bonding between the coatings and the substrates was obtained. Rapid directional so- lidification was found at the interface where the growth direction was perpendicular to the interface. The coating were mainlybuilt up by Ni3 Cr2, NiTi,SiC, TiC andT-Ni. The laser cladding corrosion was pitting corrosion and the 45 steel substrate was general corrosion in 3.5%NaC1 salt atmosphere. The corrosion rate of coating was only half of 45 steel matrix, electrochemi- cal tests showed that the corrosion potential of coating is more positive than 45 steel, and the density of the electric current is also less than that of 45 steel.

关 键 词：激光熔覆 镍基合金 耐腐蚀性能 

分 类 号：TG178[金属学及工艺—金属表面处理]