Low roughness thin diamond films produced at moderate temperatures using microwave plasma assisted chemical vapour deposition process

Diamond coatings on pure titanium substrates are of interest for tribological and biomedical implants; however, due to different thermal expansion coefficients of the two materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty in achieving very high nucleation density, it is hard to deposit adherent thin diamond layers on titanium. The aim of this research work is to successfully produce smooth and well adherent diamond coatings on a pure Ti substrate using the microwave plasma chemical vapour deposition (MWPCVD) method. The effects of applying two kinds of gas mixtures (H₂/CH₄ and Ar/H₂/CH₄) during diamond deposition on the pure Ti substrate are studied. The morphology, surface roughness, diamond crystal orientation and purity are obtained by characterising the sample with field emission electron microscopy (FESEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and Raman spectroscopy respectively.