Abstract
To clarify the mechanism of distortion of cast core for porcelain fusing, the deflection of precious alloys at high temperatures was measured. The alloy composition was 80-90wt% Au, 0-20Pt, 0-10Pd. Deflection (bending) of the specimen was detected by two differential transformers. The load of 2.0gwt was necessary to measure it stably.
The deflection decreased with increase of Au and Pd contents and with decrease of Pt content. Minimum deflection was obtained in the 80-90wt% Au, 1-10Pt, 9-10Pd range. 80Au-20Pd alloy gave the maximum deflection. The deflection-beginning temperature increased with increase of Au and Pd contents and with decrease of Pt content. Both properties had a significant correlation. The alloy which deflect large begins to bend at low temperatures.
