热喷涂合成Fe_3Al基涂层的高温摩擦学特性

Tribological properties of thermal spray formed Fe_3Al-based coatings at elevated temperature

采用自制的新型热喷涂粉芯丝材和高速电弧喷涂技术成功制备出Fe3Al金属化合物基合金涂层,对涂层的组织、成分和相结构进行了初步分析,并测试了涂层在室温至650℃的摩擦学特性。结果表明:Fe3Al涂层的基体相由含29%Al(摩尔分数)的Fe3Al和FeAl二相混合物组成,Fe3Al/WC涂层基体为Fe 26%Al(摩尔分数)合金;添加少量WC硬质相的Fe3Al/WC涂层具有良好的高温减摩特性和耐磨性,450℃和650℃其相对耐磨性分别比20g钢高1.92倍和9.23倍;WC/W2C硬质相对Fe3Al基体的强化作用,以及涂层表面形成具有自保护作用的高硬度致密氧化膜是Fe3Al/WC涂层高温耐磨性提高的主要原因。

Two kinds of novel cored wires for producing Fe3Albased intermetallic compound alloy coatings by using high velocity arc spray technique were developed. The microstructure, chemical composition and phase structure of Fe3Albased coatings were investigated. The tribological properties of thermal spray formed Fe3Albased coatings at temperature ranging up to 650 ℃ were determined on a pinondisk type wear tester. Results show that: the matrix consists of Fe3Al and FeAl phases, which have the average chemical composition of 29%Al(mole fraction); the matrix of Fe3Al/WC composite coating consists of 26%Al(mole fraction); Fe3Al/WC composite coating exhibits excellent friction reduction and wear resistance at elevated temperature. The relative wear resistance of Fe3Al/WC composite coating is 1.92 times and 9.23 times higher than that of the mild steel at temperature of 450 ℃ and 650 ℃, respectively. The main reasons for wear resistance improvement are the reinforcement of WC/W2C hard particles to the Fe3Al alloy matrix and the formation of selfprotective continuous oxide film on the composite coating surface at elevated temperature.