Abstract
This experiment was carried out to examine whether the post-firing heat treatment is effective in increasing the hardness of metal-ceramic alloy of the Pd-Au-Ag-Sn system. Precipitation hardening by holding at 600°C after simulated complete porcelain firing in a metal-ceramic alloy of the Pd-Au-Ag-Sn system was examined by observing the change in hardness, crystal structure, and microstructure using a hardness test, X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). The hardness of the alloy increased apparently by holding the specimen at 600°C for 30 min after simulated complete porcelain firing. The formation of fine grain interior precipitates during holding at 600°C caused the formation of lattice strain in the grain interior, resulting in apparent hardening. The faster cooling rate (stage 0) during simulated complete porcelain firing resulted in more effective precipitation hardening during holding at 600°C. From the above results, an appropriate post-firing heat treatment, such as holding at 600°C for 30 min after complete porcelain firing may increase the durability of metal-ceramic prostheses composed of Pd-Au-Ag-Sn alloy.
Published Version
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