Hardening effect of pre- and post-firing heat treatment for a firing-simulated Au-Pd-In metal-ceramic alloy

The hardening effect of the pre- and post-firing heat treatments and their dual treatment was examined for a firing-simulated Au-Pd-In metal-ceramic alloy to determine if an additional post-firing heat treatment is effective in the hardening of an Au-Pd-In metal-ceramic alloy as well as to compare the hardening effects of pre- and post-firing heat treatments for a firing-simulated Au-Pd-In metal-ceramic alloy. The post-firing heat treatment was much more effective than the pre-firing heat treatment or dual treatments. The hardening effect of the pre- and post-firing heat treatments was caused by the induction of fine grain interior precipitation. In the pre-firing heat-treated specimen after casting, the apparent hardening was achieved during simulated porcelain firing, but an additional post-firing heat treatment did not introduce severe grain interior precipitation, resulting in very weak hardening. In the as-cast specimen without the pre-firing heat treatment, apparent hardening by grain interior precipitation was achieved only by post-firing heat treatment and not by simulated porcelain firing.