退火对AlTiN多层薄膜结构及力学性能影响

使用TiAl合金靶,利用中频反应磁控溅射系统,通过交替改变氮气流量的方法,在高速钢(W18Cr4V)基体上沉积了一组氮含量周期性改变的AlTiN多层薄膜,并分别在600,700和800 ℃下真空退火热处理. 利用X射线衍射仪、场发射扫描电镜和高分辨透射电镜等方法研究了沉积态和退火态AlTiN多层薄膜组织和微观结构;AlTiN多层薄膜的力学和膜基结合性能用纳米压痕硬度仪、摩擦磨损仪以及划痕试验仪得到. 研究表明,采用沉积过程中周期改变氮气流量的方法,可以制备出稳定的、力学性能良好的AlTiN多层薄膜. 80 关键词： AlTiN多层薄膜 退火 微观结构 力学性能

Effect of annealing on microstructure and mechanical propertiesof AlTiN multilayer coatings

The AlTiN composition multilayer coatings with a periodic change in nitrogen content are deposited on high speed steel (W18Cr4V) substrates with a medium-frequency reactive magnetron sputtering system and TiAl targets and by alternately changing nitrogen flux during deposition. These of coatings are annealed separately at temperatures of 600, 700 and 800 ℃ in vacuum for 5 hours. Their microstructures are studied by x-ray diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy, while their mechanical behaviors and adhesion properties are investigated using nano-indenter, scratch test, and friction and wear instrument. The results show that the AlTiN composition multilayer coatings obtained by alternately changing nitrogen flux during deposition possess stable and good mechanical properties. After 800 ℃ vacuum annealing, the interface of AlTiN multilayer coating is still very clear. Annealing increases crystallization degree and grain size of AlTiN multilayer coating, but the crystallization degree of high nitrogen content layer is still higher than that of low nitrogen content layer. After vacuum annealing, the hardness of AlTiN multilayer coating reduceds. The hardness of AlTiN multilayer coating after 800 ℃ annealing is larger than after 600 ℃ annealing, but as the annealing temperature increases, wear resistance and anti-spalling performance of AlTiN multilayer coatings decrease dramatically.