高速电弧喷涂Fe-Al/WC复合涂层的高温摩擦磨损特性

Friction and Wear Behavior of High Velocity Arc Sprayed Fe-Al/WC Composite Coatings at Elevated Temperature

采用滑动磨损试验方法研究在室温至650℃温度下高速电弧喷涂Fe-Al/WC金属间化合物复合涂层与Si3N4陶瓷球配副时的摩擦磨损特性,并探讨复合涂层的高温摩擦磨损机理。结果表明,随着试验温度的升高,Fe-Al/WC复合涂层的摩擦系数降低,而磨损率仍保持在较低的水平。高温下复合涂层滑动摩擦系数降低的主要原因是由于磨损面发生摩擦氧化反应而形成的起到固体润滑的作用氧化物保护层。剥层磨损是Fe-Al/WC复合涂层高温磨损的主要机理。涂层中Fe3Al和FeAl金属间化合物相较高的高温强度和硬度,能有效地阻碍裂纹的产生、扩展及扁平颗粒的断裂,从而使复合涂层表现出优异的高温耐磨性。650℃时Fe-Al/WC复合涂层的磨损率有所提高,这可能与高温下涂层表面WC颗粒的氧化和脱碳分解有关。

The friction and wear behavior of FeAl/WC intermetallic coating against Si3N4 under dry sliding from room temperature to 650℃ was investigated using a ballondisc tribotester, and the mechanism of high temperature friction and wear was discussed The coatings were deposited onto 20g low carbon steel substrates using high velocity arc spraying (HVAS) and cored wires The results indicate that the friction coefficient of the FeAl/WC composite coating decreased significantly with the increased temperature, and the composite coating exhibited low wear rate in the test temperature range The reason of the friction coefficient decreasing at elevated temperatures is that protective oxide film formed on the worn surface of FeAl/WC composite coating during sliding wear process, which act as a solid lubricant The delamination is the predominant wear mechanism of the coatings at elevated temperatures The Fe3Al and FeAl intermetallics with higher strength and hardness at elevated temperatures in the coating can effectively resist crack initiation, propagation and splat fracture, thus resulting in excellent high temperature wear resistance The slight increase of wear rate at 650℃ may be caused by oxidation and decarburization of WC hard phase on the surface of composite coating