亚微米WC添加对超音速火焰喷涂WC-Co涂层磨损性能影响

采用超音速火焰喷涂方法(HVOF)在304不锈钢基体表面制备WC和WC-12Co的复合涂层WC-Co,研究亚微米WC的添加对涂层相组成、显微硬度、耐磨性能和表面形貌的影响。利用X射线衍射、压痕法、往复式摩擦磨损实验和扫描电子显微镜(SEM)分别对涂层的相组成、显微硬度、磨损性能和表面形貌进行分析测试,并分析涂层的磨损过程和机制。结果表明,添加质量分数5%的亚微米WC颗粒显著提高了涂层的显微硬度(16.3%);增强了涂层的耐磨性,磨损率从6.09×10-7 mm3/Nm减小到5.15×10-7 mm3/Nm(减小13.8%);亚微米WC颗粒喷涂后在涂层中保持了WC相,并主要存在于WC-Co扁平粒子界面和孔隙。基于涂层中扁平粒子的结合特性与磨损失效特征,建立强化模型,分析亚微米WC颗粒对涂层扁平粒子界面的强化机制。

Effects of Submicron WC Particles Addition on Wear Performances of HVOF Sprayed WC-Co Coatings

The coatings composed of WC, WC-12Co and WC-CO were perpared on 304 stainless steel by HVOF. The effect of the addition of submicronsized WC particles on the phase composition, microhardness and wear resistance of high velocity oxyfuel sprayed WC-12Co coatings was investigated. The results show that the addition of 5% submicronsized WC particles bring about 16.3% increase in microhardness, and the wear resistance is enhanced by 13.8% decrease in wear rate from 6.09×10^-7mm³/Nm to 5.15×10^-7mm³/Nm. The XRD results show that the coatings are mainly composed of WC phase with a little W₂C phase, the addition of submicronsized WC does not induce the large production of deleterious phases. The strengthening effect attaining at the interface of the splats and the pore of the coating by the addition of the submicronsized WC particles is also elucidated. Based on the binding properties of splats and the wear failure characteristics of the coating, the strengthening model is built to research the interface of the submicronsized WC particles reinforce WC-Co splats.