超细结构WC-η涂层的制备及其耐熔锌腐蚀性能  

Fabrication of Ultrafine-structured WC-η Coating and Its Corrosion Resistance to Molten Zinc

作　　者：由德强 王海滨[1] 刘雪梅[1] 王学政[1] 宋晓艳[1] 

机构地区：[1]北京工业大学新型功能材料教育部重点实验室,北京100124

出　　处：《稀有金属材料与工程》2017年第8期2254-2259,共6页Rare Metal Materials and Engineering

基　　金：国家高技术研究发展计划("863"计划)(2013AA032001);北京市自然科学基金重点项目(2131001);北京市自然科学基金(2154045)

摘　　要：以钨氧化物、钴氧化物和炭黑为原料,采用创新的原位反应技术快速合成超细WC-η复合粉,在优化的工艺条件下制备复合粉中只含有WC和Co6W6C相,粉末平均粒径为260 nm。复合粉经团聚造粒制备得到具有高致密性和良好流动性的热喷涂粉末,以此粉末作为喂料,利用超音速火焰喷涂技术制备得到超细结构的WC基涂层,其平均显微硬度(HV0.3)达到(14060±340)MPa,孔隙率仅约为0.3%。熔融锌腐蚀结果表明,制备的超细结构WC基涂层具有良好的耐熔锌腐蚀性能,其腐蚀机制主要是锌液沿微裂纹扩散导致涂层自表层向内部出现缓慢的溶解腐蚀,并逐渐形成贯穿性裂纹而引起涂层材料的大块剥落。The ultrafine WC-η composite powder was rapidly synthesized by a novel technique of in situ reactions using tungsten oxide, cobalt oxide and carbon black as raw materials. Under the optimized process conditions, the as-synthesized composite powder has a mean particle size of 260 nm, containing only WC and η phases. Then the composite powder was agglomerated into the thermal spray powder with high density and good flowability. Afterwards, with this powder as the feedstock, the ultrafine-structured WC-based coating was fabricated by high-velocity oxy-fuel spraying technique. The fabricated coating has an average hardness（HV0.3） as high as（14 060±340） MPa and only a porosity of 0.3%. Results indicate that the ultrafine-structured WC-based coating exhibits excellent corrosion resistance to molten zinc. The corrosion mechanism can be explained by the slow dissolving of the coating matrix from the surface layer to the inner area caused by the diffusion of molten zinc along micro-cracks, which is then followed by the formation of penetrative cracks and subsequent massive exfoliation of coating materials.

关 键 词：原位合成 WC-η复合粉 超音速火焰喷涂 WC基涂层 耐锌蚀性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]