磁性アタッチメント用キーパーと金銀パラジウム合金との鋳接 第３報 埋没材の影響

Abstract

A cast-soldering method is used for the keepers of magnetic attachments. However, there have been few studies concerning the effects of the cast-soldering method on keepers. In this study, the cast-soldering method was investigated by changing the cast investment material.Two commercially available keepers and a 12% Au-Ag-Pd alloy were used. Two conventional, and one quick-heating-types of gypsum-bonded investment were used. Cast-soldering was performed at a mold temperature of 700°C for 30 minutes using a vacuum-pressure-type casting machine. After cast-soldering, the interface between the keeper and the casting alloy was observed by metallic microscopy and scanning electron microscopy. The interface was also analyzed with an X-ray electron microprobe.A black layer (consisting of a reaction layer and a gap) was observed between keeper and Au-Ag-Pd alloy. The black layer was smallest with the conventional gypsum-bonded investment (cristobalite type), compared with the other. When using the quick-heating-type of gypsum-bonded, and gypsum-bonded (cristobalite and quartz type), investment, the black layer was equal to or larger than that when using the conventional type of gypsum-bonded investment (cristobalite type).The finding suggests that the conventional gypsum-bonded investment (cristobalite type) is preferred for the cast-soldering method of keepers.