铸钢表面电火花沉积WC-8Co涂层的高温性能  

High temperature properties of WC-8Co alloy coating deposited on cast steel by electro-spark deposition

作　　者：王建升[1] 张太萍[1] 李刚[1] 唐明奇[1] 冯在强[1] 

机构地区：[1]华北水利水电大学机械学院,河南郑州450011

出　　处：《材料热处理学报》2016年第3期150-154,共5页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51301070)

摘　　要：采用新型电火花沉积设备,把WC-8Co陶瓷硬质合金材料沉积在铸钢材料上,制备了电火花沉积合金涂层,用SEM、XRD等技术研究了沉积层在500℃的高温耐磨性和800℃高温氧化100 h后氧化膜形貌图、组织结构和高温抗氧化性能。结果表明：沉积层厚度为20-30μm。500℃高温条件下沉积层的耐磨性比基体提高了3.3倍,500℃高温条件下沉积层的磨损机理主要是粘着磨损、疲劳磨损、氧化磨损和磨粒磨损的综合作用。800℃高温条件下沉积层氧化100 h后的氧化膜的厚度约为10μm;氧化膜主要由FeFe2O4、Fe2O3、Fe5C2和Fe2W物相组成;800℃高温下沉积层抗氧化性能比基体的抗氧化性能提高了4.8倍。细小弥散分布的硬质相和致密的氧化膜极大提高了沉积层的抗高温磨损性能和抗高温氧化性能。The ceramic cemented carbide of WC-8Co alloy was deposited on the surface of the cast steel by electro-spark deposition（ ESD）process and alloy coating was formed. The high temperature wear-resistance at 500 ℃ in air,the microstructure,the surface morphology and the high temperature oxidation resistance at 800 ℃ for 100 h in air of the coatings were studied by scanning electron microscopy（ SEM） and X-ray diffraction（ XRD）. The results indicate that the coating has a thickness of 20-30 μm and the coating has better high temperature wear resistance which is 3. 3 times higher than that of the cast steel substrate at 500 ℃. The wear mechanism of the coating includes adhesion wear,fatigue wear,oxidization wear and abrasive wear at 500 ℃. The dense oxide film has a thickness of 10 μm for WC-8Co coating at 800 ℃ in air for 100 h and the primary phases in continuous oxide scales of coatings are Fe Fe2O4、Fe2O3、Fe5C2and Fe2 W. Their oxidation kinetic curves of oxide scales follow similar linear law. Their oxidation resistance of the WC-8Co alloy coating is4. 8 times higher than that of the substrate. It is clear that the changes in the oxide nature and fine microstructure played a critical role in increasing the high temperature wear resistance and high temperature oxidation resistance of the coating.

关 键 词：电火花沉积 WC-8Co硬质合金 高温耐磨性 高温氧化性 

分 类 号：TG174.44[金属学及工艺—金属表面处理]