TA2表面电火花沉积Zr/WC复合涂层特性及界面行为研究

Coating Characters and Interface Behavior between TA2 and Zr/WC Coating Produced by Electro-spark Deposition

目的通过在TA2表面进行电火花沉积改变其表面性能。方法采用电火花沉积技术,在基体TA2表面制备Zr/WC复合涂层,然后分别用扫描电镜（SEM）、能谱分析仪（EDX）、X射线应力分析仪、显微硬度计和摩擦磨损试验机分析涂层的微观组织、化学成分分布、残余应力、显微硬度分布以及涂层的耐磨性。结果复合涂层连续、均匀,厚度约为50~80μm;涂层表面不平整,存在很多小坑和粘连,涂层内部有少量气孔和裂纹;复合涂层与基体的主要元素Ti、Zr、W之间发生相互扩散,并发生冶金反应;经过电火花沉积后TA2表面存在较大的残余应力,通过改变工艺参数可有效控制残余应力;复合涂层表面显微硬度值最高能达到960.5HV200g,约为基体的4倍;经过电火花沉积Zr/WC复合涂层的试样磨损量远远小于TA2试样,ε_w=4.1,沉积层的耐磨性比基体材料提高了3.1倍,经电火花沉积制备复合涂层后表面的耐磨性显著提高。结论在TA2表面电火花沉积Zr/WC复合涂层可以改善其表面性能。

Objective To study the Zr/WC coating character and behavior on the surface of TA2 by electro-spark depositionMethods The microstructure, the chemical composition distribution, the residual stress, the micro-hardness distribution and the relative wear resistance were received by canning electron micro-scopy （SEM）, energy dispersion spectrum （EDX）, X-ray stress analyser, hardness meter and wear tester. Results The deposited layer was continuous and uniform. The thickness was about 50 μm to 80 μm, the coating surface was not flat, there were a lot of small pits and adhesion. The coating section had a small amount of porosity and crack. Mutual diffusion of main elements happened between coating surface and substrate. The obtained coating was a composite coating by metallurgical reaction between Ti, Zr, and WC. Residual stresses existed in the coating and the residual stress of the property can be controlled by changing the technological parameters. The micro-hardness of the coating surface was about 4 times as that of the substrate, the wear quality of Zr/WC composite coating was much less than that of TA2, εw = 4.1, the relative wear resistance of the deposited layer was increased by 3.1 times, the wear resistance improved significantly. Conclusion The performance of the substrate can be improved by TA2 and Zr/WC coating.