超音速火焰喷涂制备纳米和微米结构WC-η涂层的耐熔锌腐蚀性能

发布时间：2018-02-01 01:47

本文关键词： WC-η复合粉纳米结构涂层韧性裂纹扩展途径耐熔锌腐蚀性能　出处：《无机材料学报》2017年08期 　论文类型：期刊论文

【摘要】：以钨氧化物、钴氧化物和炭黑为原料,通过原位还原碳化反应制备纳米WC-η(η为Co_3W_3C、Co_6W_6C等缺碳相)复合粉,粉末平均粒径为155 nm。该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。以此纳米结构和商业化的微米结构低碳WC-12Co粉末作为喂料,通过超音速火焰喷涂制备硬质合金涂层。结果表明,纳米结构涂层中生成了一定量等轴状的W2C相,裂纹主要沿晶界或相界面扩展,而微米结构涂层中除W_2C外还含有较多的W相,主要包裹在WC颗粒表面,穿晶断裂比例较高,裂纹扩展路径较平滑。由于纳米结构涂层组织致密、晶粒细小、界面积大,因此比微米结构涂层具有更高的硬度和断裂韧性。两种涂层在熔融锌液中浸泡200 h后,微米结构涂层中产生了较多的横向和纵向裂纹,导致材料的大面积剥落和基材腐蚀;纳米结构涂层中没有发生锌的浸蚀,在局部产生了少量纵向裂纹,裂纹间隙被钨钴氧化物所填充,反而抑制了熔锌对涂层的腐蚀,因此纳米结构涂层表现出更高的耐熔锌腐蚀性能。
[Abstract]:Using tungsten oxide, cobalt oxide and carbon black as raw materials, nanocrystalline WC- 畏 (畏 as CO _ 3W _ 3C _ 3C _ C _ 3C _ 6W _ 6C) composite powder was prepared by in-situ reduction carbonization reaction. The average particle size of the powder is 155. The composite powder was prepared by agglomeration granulation to obtain high density and good fluidity of thermal spraying powder. The nanostructured and commercial micron structure low carbon WC-12Co powder was used as feedstock. Cemented carbide coatings were prepared by supersonic flame spraying. The results showed that a certain amount of equiaxed W2C phase was formed in the nanostructured coatings, and the cracks mainly propagated along the grain boundaries or phase interfaces. In addition to W2C, there are more W phases in micron structure coatings, which are mainly wrapped on the surface of WC particles. The transgranular fracture ratio is higher and the crack propagation path is smoother. The microstructure of nanostructured coatings is compact. Because the grain size is small and the boundary area is large, the hardness and fracture toughness of the two coatings are higher than those of the micron coating, and the two coatings are immersed in molten zinc solution for 200 h. There are many transverse and longitudinal cracks in the micrometer coating, which lead to the spalling of the material and the corrosion of the substrate. There is no zinc erosion in nanostructured coatings and a small number of longitudinal cracks occur locally. The cracks are filled with tungsten and cobalt oxide and the corrosion of the coatings is inhibited by zinc melting. Therefore, nanostructured coatings exhibit higher corrosion resistance to molten zinc.
【作者单位】：北京工业大学材料科学与工程学院新型功能材料教育部重点实验室;
【基金】：国家自然科学基金(51601004) 北京市自然科学基金重点项目(2131001);北京市自然科学基金(2154045)~~
【分类号】：TG174.4
【正文快照】： 热镀锌工艺以其低成本,方法易行,制备的镀锌零部件在大气、海水、土壤等环境中具有较高的耐蚀性能,是目前广泛应用的金属防锈方法之一[1-4]。但是,热镀锌板生产线中使用的沉没辊、稳定辊等部件长期处于460~650℃熔融锌或锌铝熔液中,受到活性很强的锌液的腐蚀和渗透,辊面易产生

【相似文献】