Effect of carbide grain size on microstructure and sliding wear behavior of HVOF-sprayed WC–12% Co coatings
Effect of carbide grain size on microstructure and sliding wear behavior of HVOF-sprayed WC–12% Co coatings
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DOI：
10.1016/s0043-1648(02)00294-6
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发表时间：
2003
期刊：
影响因子：
5
通讯作者：
Qiaoqin Yang;T. Senda;A. Ohmori
中科院分区：
文献类型：
--
作者：
Qiaoqin Yang;T. Senda;A. Ohmori
为了研究碳化物晶粒尺寸对 WC-Co 涂层磨损行为的影响，采用高速火焰喷涂 (HVOF) 系统，采用三种具有不同碳化物尺寸分布的团聚 WC-12% Co 粉末，热喷涂出低 WC 分解程度的涂层。涂层的表征表明，涂层的平均碳化物晶粒尺寸为0.8、1.4和2.8μm，碳化物晶粒尺寸的减小导致WC的分解程度略高。使用烧结氧化铝（Al2O3）作为配合材料进行干滑动摩擦和磨损测试。无论测试条件和碳化物晶粒尺寸如何，涂层的摩擦系数几乎恒定。涂层的具体磨损率非常低~10−6mm3/(Nm)，并且随着碳化物晶粒尺寸的增加而增加。对磨损轨道的微观分析表明，粘结剂挤出和碳化物去除或碳化物断裂是主要的材料去除机制。挤出的钴充当粘合剂，在磨损表面上形成延展性、致密且粘合良好的摩擦膜，保护表面免受进一步磨损，降低涂层的磨损率。因为单个碳化物颗粒的拉出对较细涂层的损害较小，并且还因为由较细碳化物组成的碎片作为第三体磨损的效果较差，所以磨损率随着涂层中碳化物尺寸的减小而降低。
In order to examine the effect of carbide grain size on the wear behavior of WC–Co coatings, coatings with low degree of decomposition of WC were thermally sprayed by a high-velocity oxy-fuel (HVOF) system from three agglomerated WC–12% Co powders with various carbide size distributions. Characterization of the coating showed that the average carbide grain sizes of the coatings were 0.8, 1.4 and 2.8μm and that a decrease in carbide grain size led to slightly higher degree of decomposition of WC. Dry sliding friction and wear tests using sintered alumina (Al2O3) as the mating material were performed. The coefficient of friction of the coatings was nearly constant regardless of the test conditions and carbide grain sizes. The specific wear rate of the coatings was very low ∼10−6mm3/(Nm) and increased with increasing carbide grain size. The microscopic analyses of the worn tracks have shown that binder extrusion followed by carbide removal or carbide fracture are the dominant material removal mechanisms. The extruded cobalt acts as binder to form a ductile, dense and well cohered tribofilm on the worn surface to protect the surface from further wear, decreasing the wear rate of the coatings. Because a pull-out of single carbide particle provides less damage to the finer coating and also because the debris consisting of finer carbides are less effective as the third-body abrasions, the wear rate decreases with decreasing carbide size in the coatings.