Abstract
Fe, In and/or Sn were added to 88Au precious alloy and 15kinds of alloys were prepared.Total concetration of the additional elements was 1wt%.Two specimens for thermal expansion measurements were cast separately from each alloy, and thermal expansion(%)and thermal expansion coefficient were determined.Maximum temperature of the measurement was 970℃.Thermal expansion coefficient was determined within 200℃ temperature range(room temperature〜200℃, 200〜400℃, 400〜600℃, 600〜800℃ and 800〜970℃)by linear regression.Below 800℃, it did not depend on the content of additional elements.Average coefficient values of this alloy system are;12.9×10-6/℃(RT〜200℃), 14.6(200〜400℃), 15.6(400〜600℃)and 17.3(600〜800℃).In the range of 800〜970℃, the coefficient strongly depended on In or Sn content, especially during the first cycle heating period.Contrasting other methods of determining thermal expansion coefficient, it was concluded that our method was the most convenient and reasonable to compare the thermal expansion coefficient of alloys and porcelains.
