Effect of acetylene content in working gas on microstructure and thermal stability of DLC coating

Jun Bi,Jihua Peng,Liejun Li,J Sun,X Liu,M Nawaz

doi:10.1051/e3sconf/202020602022

Abstract

The DLC coatings were deposited onto the surface of 304 stainless steel by using PE-CVD method and Ar+C2H2 as working gas. The effects of the methane content in the working gas on the structure, hardness, thermal stability of the coating were analyzed by means of SEM, FTIR, Raman and nano-indenter. It is found that controlling methane content in the work gas can be used as an effective means to modulate the structure and performance of the DLC coating. With reducing methane content in the gas mixture, the surface sputtering effect by Ar+ is enhanced, which leads a drop of hydrogen content in the coating. A high sp3C-C content in the DLC coating can be obtained by selecting an appropriate methane flow, which derives a combination of high hardness and good thermal stability for the coating. a combination of high hardness and good thermal stability for the coating.

Highlights

DLC films have great application potential in mechanical, electronic, optical, even aerospace, biomedical and other fields because of their versatile property [1,2,3,4]
DLC films prepared from acetylene and other hydrocarbon gases often contain a large number of hydrogen elements
Three DLC coatings were deposited onto the 304 stainless steel surface under the same processing condition, except for selecting a different C2H2/Ar flow ratio mixture gas, i.e., 100%, 75% and 50%

Summary

Introduction

DLC films have great application potential in mechanical, electronic, optical, even aerospace, biomedical and other fields because of their versatile property [1,2,3,4]. There were a few study about the effects of hydrocarbon mixture gas on DLC, such as methane+hydrogen, and methane+butane argon [6,7]. Three DLC coatings were deposited onto the 304 stainless steel surface under the same processing condition, except for selecting a different C2H2/Ar flow ratio mixture gas, i.e., 100%, 75% and 50%. During the a-C:H deposition, the vacuum chamber held 1 Pa, the auxiliary magnetic field current was 4A, and the deposition lasted for 90 minutes.Three working gas were chosen, i.e., Ar: C2H2 flow ratio 0:100, 25:75, 50:50 respectively.

Results and discussion

Raman spectrum and hardness of DLC Coatings

Conclusion