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２報 鋳造方法の影響

Abstract

A cast-soldering method was 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 casting methods.Two commercially available keepers and a 12% Au-Ag-Pd casting alloy were used. Cast-soldering was performed at a mold temperature of 700°C for 30 minutes using three types of casting machines (suction pressure type, vacuum pressure type, and centrifugal type). After cast-soldering, the interface between the keeper and the casting alloy was observed by metallic microscopy and scanning electron microscopy (SEM). The interface was also analyzed with an X-ray electron microprobe.Microscopic observation revealed a black layer between the keeper and the casting alloy in all specimens. Scanning electron microscopy and X-ray electron microprobe analysis indicated that the black layer was composed of an oxidation layer with Fe and a gap. The black layer was larger with the centrifugation type casting machine than by the other methods. After using this type of casting machine, gaps and cavity-like casting defects were observed in the bottom of the specimen.The results suggested that the vacuum pressure type casting machine is desirabe for the cast-soldering of keepers.