Oxidation behaviour of titanium coated copper substrate

In order to enhance the oxidation resistance of a copper substrate, titaniu m was added by inward diffusion into the surface of oxygen free high conduc tivity (OFHC) copper by a pack cementation process. Microstructural examina tion revealed that the specimen surface zone consists of three layers, the outermost layer is the transformation product of beta phase which was forme d at the diffusion temperature and contains alpha -Ti and Ti2Cu, the interm ediate 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 an d 800 degreesC indicated a decrease in the oxidation rate by a factor of mo re than two orders of magnitude. While uncoated copper samples formed a rat her thick oxide scale at these temperatures, the presence of intermetallic compound layers effectively increased the oxidation resistance and protecte d the copper substrate. (C) 2001 Elsevier Science B.V. All rights reserved.