Microstructure and mechanical properties of Ti/AlTiN/Ti-diamondlike carbon composite coatings on steel

摘要

Ti/AlTiN/Ti-diamondlike carbon (DLC) composite coatings were deposited by mid-frequency magnetron sputtering and Hall ion source-assisted deposition on high-speed steel W_(18)Cr_4V substrates. The coating microstructure and mechanical properties, including hardness, elastic modulus, coefficient of friction, and wear properties were investigated by scanning electron microscopy, Raman spectroscopy, scratch and ball-on-disk friction tests, respectively. Fairly smooth composite coating with strong interfacial adhesion and good mechanical properties was produced. The substrate bias increases sp~3 bonds contents in the DLC layer, thus coating hardness increased from 14 to 24 GPa and elastic modulus from 190 to 230 GPa with the increased substrate bias. Adhesion of interfaces between Ti-DLC and AlTiN layer, AlTiN and the steel substrate decreased with the substrate bias. The coefficient of friction is between 0.10 and 0.15, except when the substrate bias is 500 V, it is 0.2. Composite coating wear resistance increased with the substrate bias.