TiN纳米薄膜的高硬度及其产生机制

The mechanism of super hardness of nanocrystallite TiN films deposited by pulsed d.c.bias multi-arc ion plating

用脉冲直流多弧离子镀方法在W18Cr4V高速钢基体上沉积具有纳米结构的TiN薄膜,用XP纳米压入仪测量薄膜的硬度,研究了其硬度产生的机制.结果表明,厚度为2-3μm、晶粒尺寸约为13-16 nm的TiN薄膜,硬度为36-43 GPa,远高于TiN的本征硬度(22-24 GPa).高温去应力退火实验证实,具有纳米结构的TiN薄膜的超高硬度不仅是由沉积过程中载能粒子轰击产生的残余应力引起,面心立方结构的TiN薄膜沿(111)密排面择优生长、纳米晶界强化以及膜层组织结构的致密性也是重要的原因.

Nanocrystallite TiN films were deposited on W18Cr4V high-speed steel （HSS） substrates using pulsed d.c. bias multi-arc ion plating, the mechanism of the super hardness of the nanocrystallite TiN films was investigated. The results show that the film thickness is 2-3 μm, the crystalline size is about 13-16 nm, and especially the nanocrystallite TiN films hold super hardness of 36-43 GPa. The measured hardness of annealed nanocrystallite TiN films at elevated temperature confirm that the super hardness of the nanocrystallite TiN films are produced not only by the ion bombardment induced residual stress within the film, but also due to the decrease of crystalline size, dense microstructure and the film deposition onto the strongly preferential orientation with the （111） plane, which is the atomic closed arrangement plane of f.c.c.TiN.