PCVD制备Ti_(1-x)Al_xN硬质薄膜的结构与硬度

CHARACTERIZATION OF MICROSTRUCTURE AND HARDNESS OF PCVD DEPOSITED Ti_(1-x)Al_xN HARD COATINGS

用直流等离子体增强化学气相沉积(PCVD)方法获得了Ti_(1-x)Al_xN硬质薄膜;考察了Al含量x及高温退火对薄膜微观结构转变过程及其硬度的影响.结果表明,制备的Ti_(1-x)Al_xN薄膜由3—10nm晶粒组成.随Al含量x增加,薄膜硬度升高,x超过0.83时,硬度开始急剧下降;结构分析证实x小于0.83,Ti_(1-x)Al_xN薄膜是固溶强化;x=0.83,薄膜中出现六方氨化铝相(h—AlN).热稳定性实验表明,Ti_(1-x)Al_xN薄膜的纳米结构和硬度在N_2环境下可以维持到900℃.

Ti_(1-x)Al_xN hard coatings have been synthesized by direct current (dc) plasma- enhanced chemical vapor deposition (PCVD). Dependences of aluminum content and annealing at elevated temperatures on the microstructure and hardness of Ti_(1-x)Al_xN coatings were investigated. The results show that plastic hardness measured by means of indentation test increases with x increas- ing up to 0.83 and then decreases. XRD measurements indicate that the coatings with x <0.83 are fcc. solid solution with 3--10 nm grain scale. When x=0.83, relatively soft h--AlN phase is precipitated in Ti_(1-x)Al_xN coating, while the coating hardness begins a dramatical decrease. Furthermore, the nano--crystalline structure and high hardness of the coating can keep up to 900℃, which indicates the synthesized coating having good thermal stability.