Investigation on formation of thin Si-B-N films on stainless steel by plasma chemical vapor deposition
Amorphous Si-B-N alloy films on SS304 stainless steel substrates prepared by using radio frequency plasma chemical vapor deposition (RF-PCVD) from the mixture gases of N2, Ar, B2H6 and SiH4. It is found that both hardness and wear resistance of the samples with film coating were improved significantly. There are N, Si, and B existing in deposited films through the XPS and the FT-IR measurement. SEM images of the film surface presents the morphology of hilly clusters composed of small particles. Energy dispersive spectrometry (EDS) and glow discharge optical emission spectrometry (GD-OES) were used to investigate the early nucleation and growth. At the early growth stage of 5 min, the continuous film formed is composed of small particles with a diameter of tens of nanometers on the substrate, suggesting that the precursor species easily nucleate on the stainless steel surface. The examination of cross-section for film coating indicates that an interface layer with diffusion forms during the deposition process, which is attributed to highly reactive species containing silicon, boron and nitrogen generated in discharging plasma. Those have high enough energy to induce diffusion effect in interface layer.