基于分形理论的超音速等离子喷涂层界面结合行为研究

Investigation on the bonding behavior of the interface within the supersonic plasma sprayed coating system based on the fractal theory

为研究结合界面形貌与涂层体系结合强度之间的关系,采用超音速等离子喷涂设备制备Fe基合金涂层,选用(Ni,Al)涂层作为黏接底层.通过改变Ar气流量,获得不同粗糙表面的黏接底层.采用对偶件拉伸法测量复合合金涂层体系的结合强度,同时引入分形理论对结合界面形貌进行定量表征,结果表明:黏接底层能显著提高涂层的结合强度,随着Ar气流量的升高,黏接底层表面分形维数不断降低,涂层体系的结合强度则呈现出先增大后减小的趋势.

In order to investigate the relationship between the interfacial morphology of the coating system and its adhesion strength, the supersonic plasma spraying equipment is employed to fabricate Fe-based alloy coating. The （Ni, Al） coating is prepared as the undercoating with different flow of Ar gas, aiming at obtaining various rough morphologies. Interfacial morphologies of the coating system are quantificationally characterized by fractal dimension（FD）. The pull-off method is used to test the adhesion strength. Result shows that the adhesion strength is obviously improved by fabricating an undercoating, and the FD of the interracial morphology decreases with the increase of the flow rate of Ar gas, while the adhesion strength will be raised at the first beginning and then decreased to a certain value.