等离子喷涂熔滴与基体的相互作用机理研究

Study of the Interaction Mechanism Between Droplet and Substrate in Plasma Spraying

以数值模拟方法研究了等离子喷涂熔滴碰撞基体后的扁平变形过程、及变形中熔滴与基体的相互作用。结果表明熔滴密度越大 ,碰撞速度越大 ,作用在基体表面的碰撞压力越大 ,扁平粒子的结合力越大。而碰撞压力的分布特点决定了粒子的结合率。在ξ>2 .5的区域碰撞压力的减弱 ,造成了扁平粒子外缘和基体结合的减弱 ,从而可能在随后的冷却变形中翘起 。

Plasma sprayed droplet impinging and flattening on a flat substrate surface is studied numerically. The interactions between droplet and substrate during droplet deformation are taken into account. The results show that the transient impact pressure upon substrate surface increases with droplet density and impact velocity, and that the higher the impact pressure, the greater the adhesion of splat to substrate.The real contact between flattened particle and substrate would be significantly influenced by pressure distribution along the surface. The drastic drop of impact pressure occurs at the area of ξ >2.5, which may be responsible for the poor contact between splat outer area and substrate.