Oxidation behaviour of titanium coated copper substrate

In order to enhance the oxidation resistance of a copper substrate, titanium was added by inward diffusion into the surface of oxygen free high conductivity (OFHC) copper by a pack cementation process. Microstructural examination revealed that the specimen surface zone consists of three layers, the outermost layer is the transformation product of β phase which was formed at the diffusion temperature and contains α-Ti and Ti2Cu, the intermediate layer is composed of intermetallic compounds including the TiCu and Ti2Cu phases, and the innermost layer contains a solid solution of titanium in copper. Static oxidation tests of coated and uncoated samples at 700 and 800°C indicated a decrease in the oxidation rate by a factor of more than two orders of magnitude. While uncoated copper samples formed a rather thick oxide scale at these temperatures, the presence of intermetallic compound layers effectively increased the oxidation resistance and protected the copper substrate.