Absorption of gas in dental gold alloys during melting

The absorption of gas during heating and melting of pure gold and of two dental gold alloys was studied by gas chromatography. The metals were melted by two methods, i.e. gas-torch and electric heating. The specimens were analysed regarding the content of hydrogen, oxygen and nitrogen. The amount of nitrogen was not measurable in all specimens. Oxygen gas occurred with rather high values in the two dental gold alloys. The hydrogen content was often larger than the solubility limit. It is proposed that hydrogen often gives pore precipitation. It is also proposed that special caution must be taken during melting to reduce the hydrogen content in the melt before casting. D-alloy (palladium) demonstrated high H and O values on gas-torch heating.