Cold spray: effect of mixing powders

冷喷涂是一种看似简单的方法，通过使用载气（通常为氮气）将粒径约为20至40微米的金属粉末加速至超音速，将金属涂层涂覆到金属、陶瓷和聚合物表面。在与待涂覆的基材撞击时，颗粒严重塑性变形并瞬间结合到基材上并彼此结合。基材的涂覆在室温下在空气中进行。粘合粉末颗粒的常用方法是在非常高的温度下进行的，温度在熔点的约80%甚至高达熔点之间，并且需要非常长的时间，至少几个小时。显然，短时间和在空气中完成涂层的事实显然是有利的;室温处理意味着避免了热损伤，也意味着可能实现不太可能的材料配对，例如嵌入金属基质中的聚合物。此外，可以制作非常厚的3D涂层，从而将该过程提升为增材制造之一。

Cold spray is a seemingly simple method to apply metal coatings to metal, ceramic and polymer surfaces by accelerating metal powders of about 20 to 40 micron particle diameter to supersonic speeds using a carrier gas, usually nitrogen. On impact with the substrate to be coated, the particles severely plastically deform and instantaneously bond to the substrate and each other. The coating of the substrate takes place in air at room temperature. The usual methods to bond powder particles are performed at very high temperatures, between about 80% of the melting point and even upto the melting point, and require very long times, at least a few hours. Clearly the short times and the fact that coatings are done in air are obviously advantageous; room temperature processing means that heat damage is avoided and also means that unlikely materials pairings are possible, such as polymers embedded in a metal matrix. Moreover, very thick 3D coatings can be made, thus elevating the process to one of additive manufacturing.