Abstract
This report presents an investigation of the eutectic point of Ag-Cu alloy (Ag-71.9wt% and Cu 28.1wt%) as a reference temperature. The melting and freezing temperatures were measured by a platinum 10% rhodium vs platinum thermocouple and a high temperature platinum resistance thermometer. The melting temperature was determined to be t68=779.46±0.02°C. On the other hand, the freezing temperature varied from 779.4 to 778.9°C, depending on the cooling rate. The mean value was t68=779.13°C which was lower than the melting temperature by 0.33°C. Changing the concentrations of silver and copper by ±2.0% of silver from the exact eutectic point, significant differences were not evident for the melting temperature. In consequence of these results, it was concluded that the Ag-Cu eutectic point (melting) can be used as a practical reference temperature.
