CHARACTERIZATION OF A SURFACE-TREATED AU-AG-CU-BASED DENTAL METAL-CERAMIC ALLOY

The oxidation of an Au-Ag-Cu-based dental metal-ceramic alloy was stud ied by multitechnique analysis, The elemental spatial distribution of the alloy components was measured by energy-dispersive x-ray imaging a nd scanning Auger microscopy and the depth-concentration profiles stud ied by XPS and Auger depth profiling. The structure of the oxidized la yer was analysed by x-ray diffraction. Special attention was paid to t he pretreatment of the oxidized alloy in order to get a suitable oxide structure, which is known to play an essential role in the porcelain/ metal interaction, The studied alloy contained several alloying compon ents, such as In, Cu and Zn, to control melting temperature, strength and porcelain adherence. Oxidation of In could be promoted and that of Cu and Zn inhibited. This is of great importance because In2O3 is kno wn to increase porcelain adherence to noble alloys, whereas CuO tends to cause discolouration of porcelain.