磁控溅射法制备W_(1-x)Al_xN薄膜的微结构与性能

Microstructure and properties of W_(1-x)Al_xN composite film fabricated by magnetron sputtering

采用磁控溅射仪制备一系列不同Al含量的W1-xAlxN薄膜,系统研究该复合膜的微结构、力学性能、高温抗氧化性能及摩擦磨损性能。结果表明,W1-xAlxN薄膜为面心立方结构,呈(200)择优生长。当Al含量(原子分数,下同)为32.4%时,复合膜中形成h-AlN相,且随Al含量增加,h-AlN含量增多。随Al含量增加,薄膜硬度先升高后降低,Al含量为32.4%时薄膜硬度最大,约为37GPa。随Al含量增加,复合膜在室温下的摩擦因数和磨损率均先减小后增大,Al含量为32.4%时达到最小值,分别为0.3和0.9×10-8mm3/(N·mm)。复合膜摩擦因数随温度升高先增大后减小,而磨损率随温度升高逐渐增大,800℃下W0.676Al0.324N薄膜的摩擦因数和磨损率分别为0.32和8.2×10-8mm3/(N·mm)。与W2N薄膜相比,W1-xAlxN薄膜的高温抗氧化性能和摩擦磨损性能显著提高。

A series of W1-xAlxN films were prepared using reactive magnetron sputtering. The microstructure, mechanical properties, friction properties and oxidation-resistance were investigated by energy dispersive spectroscopy （EDS）, X-ray diffraction （XRD）, nano-indentation, high-temperature ball-on-disc tribo-meter, Bruker 3D profiler and annealing oven. The results indicate that the Wl-xAlxN films have a fcc crystal structure with a （200） preferential orientation. As the Al atom fraction is 32.4%, the h-AlN phase appears. With increasing Al content, h-AlN content increases, the hardness first increases and then decreases, the maximum hardness is about 37GPa as the Al atom fraction is 32.4%. At room temperature, friction coefficient and wear rate of W1-xAlxN films first decrease and then increase with increasing Al content. The minimum values of friction coefficient and wear rate are 0.3 and 0.9×10^-8 mm^3/（N-mm） respectively when Al content is 32.4%. With increasing temperature, the friction coefficient of W0.676Al0.324N films increases and then decreases, however, the wear rate increases gradually. The friction coefficient and wear rate of W1-xAlxN composite films are 0.32 and 8.2×10^-8 mm^3/（N.mm） when temperature is 800 ℃. Compared with W2N films, the W1-xAlxN composite films have much better oxidation resistance and friction property.