Preparation and Mechanical Characterization of Nanocrystalline Diamond Films on Aluminum Oxide Substrates

Nanocrystalline diamond (NCD) films were prepared on polycrystalline aluminum oxide (Al2O3) substrates by microwave plasma chemical vapor deposition (MPCVD) technique using Ar/CH4/CO2 plasma. The main objective is to study the structure and mechanical properties of the NCD films. The NCD films micrograph were examined by scanning electron microscopy (SEM) and atom force microscopy (AFM). The structure and phase composition of the films were analyzed by X-ray diffraction (XRD) and visible Raman spectroscopy. Friction testing machine was used to test the friction coefficient of the films. It was found that the diamond films possess better structure and smooth surface. Compared to Al2O3 substrates, the friction coefficient of the NCD films was smaller and the wear resistance was improved significantly.