Co/介孔WC激光复合涂层的显微结构与高温磨损性能研究  

Microstructure and High Temperature Wear Resistance Performance of Co/Mesoporous WC Laser Composite Coating

作　　者：张群莉[1] 徐卫仙[1] 姚建华[1] 陈赵扬[2] 马淳安[2] 

机构地区：[1]浙江工业大学激光加工技术工程研究中心,浙江杭州310014 [2]浙江工业大学化学工程学院,浙江杭州310014

出　　处：《中国激光》2014年第5期73-78,共6页Chinese Journal of Lasers

基　　金：浙江省重点科技创新团队项目(2010R50002);浙江省自然科学基金青年基金项目(LQ13E050012)

摘　　要：以H13钢为基体材料,以Co基合金和同粒径范围介孔WC的混合粉末为合金材料,采用半导体激光器在基体表面进行激光熔覆,通过介孔WC的特殊结构,获得均匀的高性能覆层。采用扫描电镜、能谱仪、X-射线衍射分析仪和显微硬度计研究熔覆层的显微组织、元素分布、相组成和显微硬度。利用高温磨损试验机对熔覆层在常温和高温下的磨损性能进行对比分析。结果表明,熔覆层主要由γ-Co以及碳化物硬质相WC、Cr3C2、(Cr,Co)23C6和Cr7C3组成。由于介孔WC颗粒对熔覆层的弥散强化和固溶强化的作用,激光熔覆层显微硬度比基体提高了2倍左右。在600℃高温下,由于碳化物硬质相的作用,熔覆层的高温耐磨性相比H13基体提高了3倍左右,熔覆层的高温磨损形式主要以氧化磨损为主。由于温度的升高,熔覆层表面形成氧化膜,从而对熔覆层进行有效保护,因此熔覆层的耐磨性随着温度的增加而提高。Diode laser is adopted to clad Co-based powder mixed with meso-porous WC with the same size range on H13 steel. High-performance coating is obtained with the help of meso-porous WC. Scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction analyzer and micro-hardness tester are used to study the microstructure, element distribution, phase composition and microhardness of the coating, respectively. The high- temperature wear testing machine is used to test the wear resistance of the cladded layer at room temperature and high temperature for a comparative analysis. The results show that the cladded layer is mainly composed of 7-Co and carbide hard phases WC, Cr3C2, （Cr, Co）23 C6 and Cr7C3. Due to the dispersion strengthening and solid solution strengthening effects of meso-porous WC particles on the cladding layer, the hardness of laser cladding layer increases by 2 times approximately when compared to that of the matrix. Because of the effect of carbide hard phases, the wear resistance of the cladded layer at 600℃ increases by 3 times related to that of the matrix H13. Oxidative wear is the predominant high temperature wearing mechanism of the coating. With the temperature rising, the oxide film forms on the surface of the cladded layer to protect the coating from high temperature erosion effectively. So the wear resistance of the cladded layer improves with the increase of temperature.

关 键 词：激光技术 激光熔覆 介孔WC 显微结构 高温耐磨性 

分 类 号：TG146.1[一般工业技术—材料科学与工程] TG174.44[金属学及工艺—金属材料]