Processing and properties of (Mo,Cr) oxycarbides from MOCVD

Abstract

A review of the coating kinetics of molybdenum and chromium oxycarbides and a study on the properties of deposited films are reported. Molybdenum carbonyl, chromium carbonyl and their mixture were used to prepare coatings at temperatures between 170 and 450 °C on SS304 or SiC substrates by a process of metal-organic chemical vapor deposition (MOCVD). The processing parameters of the coatings, such as the evaporation of precursors, coating pressure and temperature, are discussed along with the coating rates, compositions and other microstructural information, so to reveal the kinetics of the coating process on two different substrates. In addition, the chemical composition, crystalline phases and microstructure of the coatings obtained in various conditions are presented with the evidence interpreted by various electron-microscopic and spectroscopic techniques, including XRD, EDS, EPMA and XPS. The dependence of some properties, such as hardness, adhesive strength and corrosive resistance of the coatings on SS 304, on their composition and the deposited phases, i.e. as a function of coating temperature and pressure, is reviewed. © 1998 John Wiley & Sons, Ltd.