The influences of heat treatment and addition of a small amount of base metal (in, Sri, and Ir) for oxidation in Au-Pt-based alloy were investigated by electron spectroscopy and scanning electron microscopy. Au-Pt-based alloys were prepared by argon-arc melting furnace and then they are heat treated. Oxidation on alloy was significantly affected by addition of base metal (in and Sri) and heat treatment. The bond strength of the alloys was not dependent on the changing heat treatment. These results indicated that the Sri and In could be effective as oxidation elements for porcelain bonding to gold alloys. (C) 2009 Elsevier B.V. All rights reserved.