The Effect of Sound on Diamond Hot Filament Chemical Vapor Deposition

This paper presents how vapor deposited coating of carbon (partially diamond) on stainless steel 304 substrate was affected by temperature, pressure and duration of deposition in conjunction with sound vibration. To do so a hot filament chemical vapor deposition apparatus was designed and fabricated. The experiments were carried out under different frequency of vibration (ranging from sonic and ultra sonic). Results show that deposition rate varies with temperature, pressure and duration under vibrating and non-vibrating conditions. It was found that the deposition rate was higher for vibrating condition than that of non-vibrating condition. In this study, the higher the temperature, pressure and duration, the higher the effectiveness of frequency of vibration on the deposition rate was obtained. During thermal CVD process, activation of reactive species was enhanced by chemical activity with the increase of temperature and pressure. By adding extra energy of sound, kinetic energy was increased more due to increase of the adsorption and diffusion rate, which causes the increase of deposition rate. A coating of carbon (partially diamond) has been deposited on the substrate, and the characterization of the coating has been done by SEM including EDX and XRD. The coating of carbon was identified by EDX, and the allotropic forms of graphite and diamond peaks of carbon are found by XRD analysis. SEM analysis shown that the microstructures of deposited coatings were more compact and smoother under higher temperature and pressure than that of lower temperature and pressure. The experimental results are compared with those available in the literature and physical explanations are provided.