A comparative study of diamond growth on tungsten wires by using methane and graphite as the carbon source

Diamond coatings on tungsten wires were made by using graphite and methane as the carbon source in a hot filament chemical vapor deposition reactor (HFCVD). The experiments were performed in order to compare the diamond coatings produced by graphite etching and by gas methane in an atomic hydrogen-rich atmosphere. Complex arrangements of tungsten wires as substrates and tungsten wires as hot filament were tested in order to verify the best way to produce diamond-coated tungsten wires in large scale. In terms of quality, diamond on tungsten wires was analyzed by Raman Spectrometry and in terms of morphology and growth rate, the analyses were carried out by Scanning Electron Microscopy (SEM). The results show that graphite etching produces more uniform diamond tubes, mainly when thinner and longer tungsten wires are used as substrate.