非标准齿形超音速火焰喷涂WC-10Co4Cr层的均匀性分析

Analysis of Uniformity of WC-10Co4Cr Coating Prepared on Non- Standard Tooth Aluminum Alloy Workpiece by High Velocity Oxy-Fuel Flame Spraying

异形面或非常复杂的曲面上的涂层的均匀性对其性能和使用寿命影响很大,而目前此类研究非常少。采用超音速火焰喷涂(HVOF)技术在6061铝非标准齿形件表面制备了WC-10Co4Cr涂层,利用X射线衍射仪(XRD)、扫描电镜(SEM)、光学显微镜和显微硬度计测试分析了涂层的微观组织、厚度分布和硬度分布,并探讨了齿形参数对涂层均匀性的影响。结果表明:所得涂层致密,与基体之间结合良好,但厚度和硬度分布不均匀;齿槽底涂层厚度偏大,硬度最低,齿顶位置涂层硬度最高,啮合面涂层硬度介于二者之间;全齿高h对齿槽底和齿顶处涂层的厚度和硬度均匀性影响不大,但h增大会导致啮合面涂层沉积厚度大幅降低,硬度略微降低;根据提出的简化齿形喷涂参数可以预测热喷涂齿形工件获得均匀涂层的可能性。

WC-10Co4Cr coating was prepared on the surface of non-standard tooth 6061 Al alloy by high velocity oxy-fuel flame spraying( HVOF). The microstructure,thickness distribution and hardness distribution of as-prepared coating were analyzed by X-ray diffraction,scanning electron microscopy,optical microscope and microhardness testing,and the effect of tooth parameters on the uniformity of the coating was also examined. Results showed that as-prepared coating was compact and had good adhesion to Al alloy substrate,but its thickness distribution and hardness distribution were uneven. Namely,the coating thickness at the bottom of the tooth was too large,and the microhardness was the lowest thereat. Besides,the coating hardness at the tooth tip was the maximum. In the meantime,tooth height had slight effect on the uniformity of coating hardness and thickness at the bottom and tip of the tooth; but incrementing tooth height led to significantly reduced thickness of the coating at the mating surface,accompanied by slight decrease in coating hardness therewith. Moreover,it was feasible to predict the possibility for obtaining uniform thermally sprayed coating on tooth workpieces while the simplified spraying parameters for tooth workpieces were considered.