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KMID : 0896219970170010047
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Journal of Daegu Health College
1997 Volume.17 No. 1 p.47 ~ p.67
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The Effect of 2wt%Au Addition on the Microstructure and Corrosion Resistance in Ag-20wt%Pd-20wt%Cu
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Lee Hwa-Sik
Bae Bong-Jin
Kim Jeong-Sook
Lee Kee-Dae
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Abstract
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The use of low-noble dental alloys in densitry has increased with the rising price of gold. A decrease in the noble metal content of such fairly complex alloys easily results in multi-phase structures. Dental Ag-Pd-Cu alloys exhibit the characteristics of age-hardenabifity. Palladium represses the sulphurization of silver, and the age-hardenability is caused by the addition of copper. In order to improve the corrosion resistance, a small amount of gold is added to the commercial alloys These alloys were melted and casted by induction electric furnace and centrifugal casting machine in AK atmosphere. They were rolled and drawn into plate and wire shape. These specimens were solution treated for 2hr at 800 C and were then quenched into iced water, and aged at 350-550℃ Microstructural characteristics of the small Au-containing Ag-Pd-Cu dental alloys were investigated by means of electron microscope observations, emergy dispersed spectra and electron probe microanalysis, and dental application was carried out by corrosion test. Principal results are as follows : It was very effective that addition of small amount of Au increased corrosion resistance in Ag base dental alloy and increasing the Pd content of Ag base alloys also increased corrosion resistance. The formation of the lamellar structure developed from grain boundaries by discontinuous precipitation. Lamella structure will contribute more to corrosion resistance and is prone to high corrosion rate.
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