Plasma enhanced magnetron sputter deposition of Ti–Si–C–N based nanocomposite coatings

Abstract

This paper reviews a Plasma Enhanced Magnetron Sputtering (PEMS) technology and a series of studies of Ti– Si–C–N nanocomposite coatings deposited using this technique. The PEMS technology is discussed briefly and compared with conventional magnetron sputter deposition. In PEMS, an electron source is used to generate plasma in addition to the magnetron plasma for both ion cleaning of the surfaces before deposition and enhanced ion bombardment during the deposition. The coatings thus obtained are very dense with nearly no columnar structure. Using this technology, many Ti–Si–C–N coatings have been prepared. These coatings are found to be nanocomposite coatings composed of nanocrystalline TiCN with grain sizes of 4.7– 100 nm in a matrix of amorphous SiC x N y . Their hardness ranges from 25 to 43 GPa and has a Si concentration up to about 3.5 at.%. They exhibit erosion resistance over 100 times better than the uncoated Ti–6Al–4V substrate. It has been observed that the toughness of the coating, or the resistance to crack formation and propagation, evaluated using H 3/ E⁎ 2, correlates well with the coating erosion resistance. The relationship among the processing parameters and the coating microstructure, nanohardness, adhesion, and erosion resistance are discussed. In addition, single and multilayered coatings have also been compared. These coatings are intended to be used against severe sand erosion for gas turbine compressor blades and vanes.