| For this project, CrN-WC coatings are investigated as a hybrid hard and tough material. The use of a hard-carbide with a corrosion-resistant nitride may produce tailored coatings with the desired combination of properties for use as a stand-alone protective coating, or as a basis for nanocrystalline diamond deposition. The work is divided into three stages. The initial study determined the viability of the CrN-WC system, and its use as an interlayer for nanocrystalline diamond. This successful study was followed by a variation of deposition conditions at low deposition temperature. By varying the deposition parameters, the microstructure, chemical, mechanical, and tribological behavior may be optimized. While the system has relatively good adhesion to silicon substrates, its adhesion to steel was lacking. Additionally, the system showed lower than expected mechanical properties. The final step increased the deposition temperature. The aim here was to increase adhesion and improve the mechanical properties. Prior results with other systems show consistent improvement of mechanical properties at elevated deposition temperatures. The high deposition temperature coatings showed marked improvement in various characteristics over their low deposition temperature cousins. |
