Study of diamond nucleation and growth on Ti6Al4V with tungsten interlayer

Diamond nucleation and growth on Ti6Al4V substrates with tungsten (W) interlayers were investigated using hot filament chemical vapor deposition (HFCVD). W interlayers were firstly deposited on Ti6Al4V substrates under different conditions by sputtering and diamond was then deposited on W-coated Ti6Al4V using the same HFCVD reactor. X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, atomic force microscopy, Raman spectroscopy, synchrotron near-edge X-ray absorption fine structure spectroscopy and Rockwell C indentation tests were used for characterization. The effect of thickness and surface morphology of W interlayer on the nucleation, growth, and adhesion of diamond on the Ti alloy was investigated. The results show that the pre-deposited W interlayers act as a diffusion barrier for carbon, and thus significantly enhancing the nucleation of diamond. In addition, the W interlayer reacts with carbon to form WC and W2C during the diamond deposition, thus enhancing the adhesion of diamond on Ti6Al4V.