Effect of Substrate Temperature, Biasing and Sputter Cleaning on the Structure and Properties of Nanostructured TiB₂ Coatings on High Speed Steel

Abstract

Fabrication and development of TiB₂-based nanostructured coatings was investigated in the present work. By varying the sputter-target power density, substrate temperature, deposition time, substrate-to-target distance, substrate biasing and substrate sputter cleaning, the relationship between the sputtered structure, properties and sputtering conditions were established. The experimental results showed that the target-to-substrate distance played a major role in the coating structure and properties. Sputter cleaning of substrate helped to improve TiB₂ coating hardness and adhesion. The deposition process could be controlled to produce a TiB₂ coating with both high hardness and good adhesion strength. This was achieved by introducing substrate sputter-cleaning and then biasing for the early stage of deposition, followed by deposition without biasing.