双丝电弧喷涂方法制备功能梯度涂层

Functionally Graded Coatings Produced by Means of Twin Wire Arc Spraying

本文介绍了一种从粘结层到面层成分和性质逐渐不同的功能梯度涂层(FGC)。在涂层制备过程中,使用了混合喷嘴,采用双丝喷涂工艺。为了提高涂层与基体的结合力,首先在基体上喷涂金属丝材作为粘结层,为提高涂层的耐磨性,又将粉末状的硬质材料喷射到含有大量的熔融丝材的火焰中制备出面层涂层。结果表明,功能梯度涂层是由纯金属部分和含有硬质材料的部分组成,涂层的微观结构、孔隙率和成分按梯度变化,喷涂制备的功能梯度涂层其性能要优于喷涂粉芯丝材制备的涂层。本文研究的目的是根据涂层的位置来设计涂层的沉积过程,从而得到所需涂层的性能。

Functionally graded coatings （FGC）, in which the composition and properties vary gradually from the bond layer to the top layer, are introduced in this study. Using a mixing nozzle, a graded coating was generated employing twin wire spraying （TWAS） process. The deposition started with a base layer of massive metallic wires for better adhesion to the substrate. At following top layers hard material, in form of powders, was injected to the massive wires to enhance the wear protection. The results show that microstructure, porosity, and compositions are gradually varied in the coatings. This is a clear indication for the better performance in as-sprayed FGC than coatings sprayed by means of cored wires. The approach was to grade the coating composition from pure metallic to composite with higher content of hard material particles. The goal of the study is to articulate the needed coating performances by customizing the layers deposited regarding to their position.