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利用超音速火焰喷涂技术将4种不同致密度WC10Co4Cr粉末制备成涂层。采用扫描电镜、X射线衍射仪、显微硬度计、表面粗糙度仪等设备对涂层的微观组织、结构特征进行分析。结果表明,随着致密度的降低,团聚烧结型粉末与基体撞击后更容易铺展,碳化钨微粒分布变得更均匀,形成的涂层具有更低的孔隙率和表面粗糙度;但是随着致密度的降低,碳化钨分解率升高,形成更多的脆硬相,最终使得涂层断裂韧性下降。由此可知,致密程度影响粉末颗粒在热喷涂过程中加热、加速和铺展状态,从而影响涂层的结构特征。
Four different densities of WC10Co4Cr powders were prepared into coatings by supersonic flame spraying. The microstructure and structure of the coating were analyzed by scanning electron microscopy, X-ray diffraction, microhardness tester and surface roughness tester. The results show that as the densification decreases, the agglomerated sintered powders spread more easily after impact with the matrix and the distribution of the tungsten carbide particles becomes more uniform, resulting in coatings with lower porosity and surface roughness; however, Lower density, tungsten carbide decomposition rate increases, the formation of more brittle hard phase, eventually making the coating fracture toughness decreased. It can be seen that the density of the powder particles in the thermal spraying process heats up, accelerates and spreading state, thus affecting the structural characteristics of the coating.