Double bias HF CVD multilayer diamond films on WC-Co cutting tools

Diamond layers are nowadays of increasing importance for mechanical applications. In our laboratory we grow diamond and DLC layers on WC-Co cutting tools using HF CVD method improved by double biasing. Optimization of growth parameters facilitates to control grain size of polycrystalline diamond layers from microcrystalline to nanocrystalline. Five steps of this process are described and demonstrated. SEM, AFM, Raman spectroscopy, and XRD were used to analyze grown diamond films. The decrease of the RMS surface roughness from 650 nm down to 50 rim was measured. Bias voltage was demonstrated to be the tool for changing the grown layer grain size. Deposition rates were increased to optimal values.