模具钢表面Co/TiC熔覆层的组织与高温磨损性能  

Microstructures and high-temperature wear behaviors of Co/TiC laser coatings on die steel

作　　者：PHAM THI HONGNGA 刘洪喜[1] 张晓伟[1] 王传琦[1] 蒋业华[1,2] 

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]胡志明市技术师范大学机械工程学院,越南胡志明市

出　　处：《光学精密工程》2013年第8期2048-2055,共8页Optics and Precision Engineering

基　　金：昆明理工大学分析测试基金资助项目(No.2010025;No.2011008)

摘　　要：利用6kW横流CO2激光器制备了Co50熔覆层和不同成分配比的Co/TiC复合涂层来改善H13模具钢表面的热磨损性能。借助X射线衍射(XRD)、扫描电子显微镜(SEM)、显微硬度计和高温摩擦磨损试验机分析了涂层的结合特征、物相组成和不同温度下的摩擦磨损性能。结果表明,当预置层粉末TiC含量(重量百分比)小于等于20%时,熔覆层与H13钢基材呈良好的冶金结合;随着TiC含量的增加,Co/TiC复合涂层截面平均显微硬度呈上升趋势,但涂层中基体相种类减少:Co+10%TiC涂层由TiCo3、Cr2Ni3和Cr-Ni-Fe-C组成,Co+20%TiC涂层由Cr2Ni3和γ-Co组成,Co+30%TiC涂层为γ-Co固溶体。Co+20%TiC涂层的高温耐磨性比Co50涂层显著提高,摩擦系数平稳;700℃时复合涂层的磨损机制主要为氧化磨损和疲劳磨损。结果显示Co+20%TiC涂层具有良好的综合性能。Co50 alloy coating and Co50 composite coatings doped with different mass fractiones of TiC were prepared by a 6 kW transverse-flow COz laser to improve the wear resistance of H13 die steel. The bonding characteristics, phase composition and wear behaviors of the coatings were investigated by X-ray diffractometry（XRD）, Scanning Electron Microscopy （SEM） and high-temperature wear tester. The experimental results indicate that Co/TiC composite coatings with the content of TiC less than 20% （weight percentage） show good metallurgical bonding characteristics with the substrate sur- face. In addition, the micro-hardness of TiC/Co based coatings increases with the TiC content, but matrix phase composition of the composite coatings tends to be simple： Co-＋-10%TiC coating consists of TiCo3, Cr2Nia and Cr-Ni-Fe-C phases, while Co＋20%TiC coating is Cr2Ni3 and γ-Co, and Co＋30~TIC coating mainly is composed of ＂/-Co solid solution. Co4-20~TiC coating shows better wear behavior than Co50 coating, as well as has a more stable friction coefficient. Moreover, the high-tem- perature wear is mainly caused by oxidation wear and fatigue wear. These results demonstrate that Co ＋ 20 %TiC composite coating has good comprehensive properties.

关 键 词：激光熔覆 模具钢 Co TiC复合涂层 高温磨损 

分 类 号：TG156.99[金属学及工艺—热处理]