离子束辅助磁控溅射沉积CrN_x薄膜结构以及力学性能研究

Characterization of Microstructures and Mechanical Properties of Sputtered Coatings

采用离子束辅助磁控溅射工艺制备CrNx薄膜,研究了不同氮气流量下薄膜微观形貌,组织结构以及力学性能的变化。采用台阶仪测量薄膜的厚度,采用场发射扫描电镜、扫描探针显微镜、X射线衍射仪测试薄膜的表面形貌特征以及组织结构,采用纳米压痕仪测试薄膜的硬度以及弹性模量。实验结果表明,随氮气流量增加,薄膜沉积速率先降低后保持稳定,粗糙度先减小后增加,相组成由Cr2N相转变为CrN相,硬度、弹性模量先增加后降低。由于Ar离子束的辅助轰击以及N离子的高反应活性,在氮气流量为10 ml/min时,获得了结构致密,表面光滑,晶粒细小,相组成为Cr2N的力学性能优异的薄膜。

The CrNx coatings were deposited by ion beam assisted magnetron sputtering on substrates of Si wafer and glass. The impacts of the synthesis conditions, including the N2 flow rate, bias voltage and pressure, on the microstructures and mechanical properties were evaluated. The CrNx coatings were characterized with X-ray diffraction, scanning electron microscopy, scanning probe microscopy, and conventional mechanical probes. The results show that The CrNx coating sig- nificantly improves the mechanical properties, and that N2 flow rate strongly affects the microstructures of the CrNx coat- ing. For instance, as the N2 flow rate increased, the deposition rate first dropped a little, and then leveled off at a stable rate;the surface roughness changed in a decrease-increase mode; but its hardness and elastic modulus varied in an in- crease-decrease mode, accompanied by a phase transition from Cr2N to CrN. At a N2 flow rate of 10 mL/min, fairly com- pact, smooth Cr2N films with good mechanical properties were obtained possibly because of the Ar bombardment and be- cause of the increased activity of N ions.