射频反应溅射(Al,Ti)N涂层的微结构与力学性能

采用Al-Ti镶嵌复合靶在不同氮分压下制备了一系列(Al,Ti)N涂层,并采用EDS,AFM,XRD,TEM和微力学探针表征了涂层的沉积速率、化学成分、微结构和力学性能,研究了氮分压对涂层的影响.结果表明,氮分压对(Al,Ti)N涂层影响显著:合适的氮分压可以得到化学计量比的(Al,Ti)N涂层,涂层为单相组织,并呈现(111)择优取向,最高硬度和弹性模量分别达到36.9GPa和476GPa.过低的氮分压不但会造成涂层贫氮,而且涂层中的Al含量偏低,硬度不高.氮分压过高,由于存在"靶中毒"现象,尽管涂层的成分无明显变化,但会大大降低其沉积速率,并使涂层形成纳米晶或非晶态结构,涂层的硬度也较低.

Microstructure and Mechanical Properties of Reactively Sputtered (Al,Ti)N Coatings

The effect of N_2 partial pressure on the microstructure and mechanical properties of reactively sputtered(Al,Ti)N coatings was studied.A series of(Al,Ti)N coatings were deposited by using Al-Ti composite target in the gas mixed with Ar and N_2.The deposition rate,composition and microstructure of the coatings were characterized by EDS,AFM,XRD,TEM and a nanoindentor was used to measure their mechanical properties.The results show that N_2 partial pressure has an important effect on the microstructure and properties of(Al,Ti)N coatings.(Al,Ti)N coating with stoichiometric ratio can be easily obtained at suitable N_2 partial pressure and the coating have single phase structure,presenting strong(111) texture.It reaches the highest hardness and elastic modulus of 36.9GPa and 476GPa.(Al,Ti)N coatings prepared at lower N_2 partial pressure show poor N and Al content and thus have low hardness.At overhigh N_2 partial pressure,the deposition rates of the coatings decrease greatly because N_2 reacts with the Al-Ti mosaic target and forms nitride layers on the target surface.Under this condition,the composition of the coatings has almost no change,and the coatings show a microstructure of nanocrystalline or amorphous and low hardness.