Ti-Si-N纳米复相薄膜及Si含量对脉冲直流PCVD镀膜质量的影响

用工业型脉冲直流等离子体增强化学气相沉积(PCVD)设备，在高速钢(W18Cr4V)表面沉积Ti-Si-N三元薄膜，研究了不同N2流量对薄膜组织及性能的影响，结果表明：随N2流量增大，膜层沉积速率及膜层中Si含量减少，薄膜组织趋于致密，膜层颗粒尺寸明显减小，划痕法临界载荷和显微硬度显著增加，硬度最高可达50GPa以上。研究发现，对应N2流量，薄膜相组成发生变化，依次存在有TiN／a-Si3N4／Si，TiN／a—Si3N4／TiSi2／Si，TiN／a—Si3N4／TiSi2三种相组成形式，分析认为，低N2或高Si效果不佳的原因在于直流PCVD是以工件为阴极，膜层中过多的Si3N4和Si将严重劣化阴极的电导性，致使膜层疏松，说明脉冲直流PCVD与射频PCVD存在很大的区别。

NANOCOMPOSITE Ti-Si-N FILMS AND EFFECT OF Si CONTENTS ON PULSED DC PCVD COATINGS QUALITY

Using an industrial type set-up of pulsed DC plasma chemical vapor deposition the Ti-Si-N coating on high speed steel (W18Cr4V) was performed. The effect of N2 flow on microstructure and interfacial bonding strength was investigated. The results show that the deposition rate and contents of Si in Ti-Si-N coating decrease with increasing N2 flow, and the film structure tends to dense, but the critical load of scratch method and the microhardness of coating increase obviously when higher N2 flow was used. The Si contents of Ti-Si-N coating decrease with increasing N2 flow, three type phases of nc-TiN/a-Si3N4/Si, nc-TiN/ a-Si3N4/TiSi2/Si, nc-TiN/a-Si3N4/TiSi2 are found in coating orderly. It is known that workpiece is cathode in DC PCVD and low conductivities of Si3N4 and Si during formation of the coating will reduce conductivity of cathode, so quality of coatings is worsened in lower N2 or higher Si content. The results illustrate that there are many differences between pulsed DC PCVD and RF PCVD.