温度对WC-WB-CoCr涂层高温摩擦磨损性能的影响

Effect of temperature on high-temperature friction and wear properties of WC-WB-CoCr coating

摘要:

采用超音速火焰喷涂(HVOF)制备了WC-WB-CoCr涂层,研究了温度对WC-WB-CoCr涂层高温摩擦磨损性能的影响。通过扫描电镜、X射线衍射和显微硬度仪对涂层的微观组织和力学性能进行了表征。通过摩擦磨损试验机和拉曼光谱仪研究了WC-WB-CoCr涂层的高温摩擦学性能和氧化产物,采用台阶仪扫描磨痕形貌并计算WC-WB-CoCr涂层的磨损率。结果表明：WC-WB-Co-Cr涂层主要由WC和CoW₂B₂组成,涂层结构致密,与基体结合紧密；随着磨损试验温度升高,涂层的摩擦系数从0.66降低到0.57,涂层的磨损率随着温度的升高而升高,但是其磨损率增长程度随着温度的升高而降低。高温磨损过程中,磨痕表面的氧化膜主要由WO₃和CoWO₄组成,且CoWO₄比WO₃表现出更好的耐高温磨损性能。涂层的主要磨损机制为疲劳磨损和黏着磨损。

关键词:超音速火焰喷涂;WC-WB-CoCr;温度;高温磨损

Abstract:

WC-WB-CoCr coatings were prepared by high velocity oxy-fuel spraying (HVOF), and the effect of temperature on the frictional wear properties of WC-WB-CoCr coatings was investigated. The microstructure and mechanical properties of the coatings were characterized by scanning electron microscopy, X-ray diffraction and microhardness tester. The high-temperature tribological properties and oxidation products of WC-WB-CoCr coatings were investigated by friction and wear testing machine and Raman spectroscopy, and the abrasion scar morphology was scanned and the wear rate of WC-WB-CoCr coatings was calculated by a surface profiler. The results showed that the WC-WB-Co-Cr coating mainly consisted of WC and CoW₂B₂, and the coating structure was dense and tightly bonded to the substrate. The friction coefficient of the coating decreased from 0.66 to 0.57 as the temperature of the wear test increased, and the wear rate of the coating increased with the increase of temperature, but the growth rate of its wear rate decreased with the increase of temperature. During high temperature wear, the oxide film on the surface of the wear marks mainly consisted of WO₃ and CoWO₄, and CoWO₄ showed better high temperature wear resistance than WO₃. The main wear mechanisms of the coating are fatigue wear and adhesive wear.

Key words:High velocity oxy-fuel spraying; WC-WB-CoCr; Temperature; High temperature wear