[Studies on Au-Ag-Pd-Cu alloys. (Part 2) Some properties on alloys containing 30 wt% Au (author's transl)].

In the previous paper, the author reported 30 wt% Au was more favourable content in Au-Ag-Pd-Cu quaternary dental alloys. In this paper, the experiment was carried out to find suitable Pd and Cu content in 30 wt% Au-Ag-Pd-Cu alloy. Pd and Cu content was changed from 5 wt% to 25 wt% and from 10 wt% to 20 wt% respectively. Ag content was balanced, and no other metals was added. Range of solidification temperature, tensile strength, elongation, hardness, corrosion resistivity and castability were tested. Results were as follows. 1) In these alloys, liquidus points were in the range of 880 degree C approximately 140 degree C, but in the majority of alloys, liquidus points were under 1100 degree C. Range of solidification temperature was more narrow in 20 wt% Cu than other Cu content. 2) The tensile strength and elongation of swaged specimens increased as Pd content increased, but in case of cast specimens, mechanical properties were the highest at 15 approximately 20 wt% Pd. The Vicker's hardness was in the range of 116 to 235. 3) The corrosion test in 0.1% Na2S solution indicated that the corrosion resistance was increased with Pd content and alloys contained more than 20 wt% Pd showed good resistance to corrosion. 4) The castability was affected by the Pd content and much decreased between 15 wt% Pd and 20 wt% Pd, but the castability of these alloys is twice as good as the alloys on the market. From these results, it seemed that the alloys containing 15 approximately 20 wt% Pd and 15 approximately 25 wt% Cu were more favourable composition to 30 wt% Au-Ag-Pd-Cu alloys.