Effects of argon addition into H2 + CH4 gas mixture on synthesis of diamond coating in glow discharge stabilized by magnetic field

Investigation of parameters of the glow discharge stabilized by magnetic field in different gas mixtures under conditions of diamond films synthesis was performed. It was shown that discharge the cathode voltage drop reaches 700 V, that significantly exceeds the typical cathode voltage drop in the glow discharge without magnetic field. Addition of argon into the working gas mixture reduces the cathode voltage drop up to 100 V. Moreover it was shown that the grain size in diamond coatings synthesized in H2+Ar+CH4 gas mixture is about 40...50 nm, while for H2+CH4 working gas mixture the grain size achieves 20 μm at the same coating deposition conditions