含WC陶瓷相电弧喷涂层耐磨粒磨损性能的研究

采用电弧喷涂含WC-CoNi金属陶瓷粉末的粉芯丝材,在低碳钢基体上制备铁基复合涂层,采用MLS-225型湿砂橡胶轮磨损试验机评价铁基复合涂层的耐磨粒磨损性能,利用光学显微镜、扫描电子显微镜和X射线衍射仪对涂层的显微组织结构、磨损表面及其相组成进行分析.结果表明:含WC陶瓷相涂层的耐磨粒磨损性能较好,相对Q235钢提高约9倍;当粉芯中WC质量分数低于25%时,随着WC含量增加,涂层的硬度和耐磨性增加;当粉芯中WC质量分数超过25%后,涂层的耐磨性有所下降;电弧喷涂含WC陶瓷相涂层的磨损机制主要为硬质相的脆性剥离和轻微的塑性切削,在磨粒磨损条件下硬度较低的金属基体先磨损,硬度较高的WC和Fe3B硬质相起到阻止石英砂磨损的作用,从而降低了涂层的磨损.

Abrasive Resistance of Arc Sprayed Coatings with a WC Ceramic Phase

Iron-based composite coatings were deposited on mild steel substrate by arc spraying cored wire with WC-CoNi ceramic powders. The abrasion wear properties were evaluated using a examined MLS-225 wet sand/rubber wheel tester. The microstructure, phase compositions and worn surface of the coatings were examined by means of optical, scanning electron microscopy and X-ray diffraction. The results show that the coatings with WC ceramic phases exhibited better abrasive wear resistance and about 9 times higher than that of the Q235 mild steel. The hardness and abrasive resistance of the coatings increased with increasing WC content in the cored wire. The abrasive wear resistance of the coating reduced when WC content was more than 25%. The metallic matrix of the coatings, due to their low hardness, were worn prior to the tungsten carbides. Brittle peeling and micro-ploughing are the major wear mechanism of the coatings. WC, FeaB ceramic phase with higher hardness played a role to resist the abrasion from silica, and thus decreases the abrasion of the coatings.