低压等离子喷涂铬涂层的性能表征

钼基材料可作为动密封环的基体材料,但其在高温高速条件下的硬度及耐磨性不够,必须在密封端面覆盖一层硬度高、耐磨性能优良、可靠性高的表面保护层--铬.目前在钼基材料上制备电镀硬铬镀层的技术还不成熟.为此,以低压等离子喷涂的方法,通过调整喷涂参数和喷涂气氛,特别是适当地控制空气分压,最终获得了均匀、致密并与基体结合良好的铬涂层.结果表明,最佳空气分压为8.0～16.0 kPa,所得涂层硬度高,耐磨性能优良.

Preparation of Chromium Coating on Mo Substrate by Low Pressure Plasma Spraying and Wear Resistance of the Coating

It is imperative to introduce chromium coating with high hardness, excellent wear resistance, and good reliability on the surface of Mo-based materials so as to retain the hardness and wear resistance of the Mo matrix used in high temperature and high sliding or rotating conditions. This, for example, is essential to the application of Mo-based materials in dynamic airproof ring. Unfortunately, conventional Cr electroplating on Mo substrate still remains unsuccessful owing to technical difficulties. Thus low-pressure plasma spraying (LPPS) was used to prepare chromium coating on Mo substrate. The wear resistance of the Cr coating was evaluated. It was found desired Cr coating could be fabricated on the Mo substrate by properly controlling the spraying parameters, in particular, the partial pressure of air in the spraying chamber. The resulting Cr coating was dense and well bonded to the Mo substrate. Moreover, it had high hardness and excellent wear resistance and could used for the protection of the Mo-matrix dynamic airproof ring.