Study of Physical Properties of 18 % Silver Mixed with Copper and Indium

Abstract

This project aimed to study the properties of 18 wt.% sterling silver metal containing 80-82% copper (Cu) and 0-2.0% indium (In) elements, respectively, comparing with 18.03 Ag silver alloys imported from overseas. Based on the physical properties of the test pieces, it can be concluded as follows: The mixing volume of copper decreased and the indium increased mixed with silver metal, making the sterling silver metal 18 wt.% dilute, resulted in a continuous decrease in the density of the test pieces. The one with a mixing rate of 18.03Ag 79.75Cu 2.02In composing of concentration of 97.54% copper and 2.46% indium had minimum density of 8.50±0.02 g/dm3. The microstructure of the test specimens did not change, since copper and indium could be melted into silver metals, becoming a silver metal of 18 wt.% in the form of a single phase solid solution. Every test piece had a dendrite microstructure with a core structure formed within the grain, caused by the metal water cooling in faster-than-balance conditions. For the color measurement of the test specimens according to the color space of the L*a*b system according to CIELAB standard, the color value changed, resulting in a change in the L* (brightness value). The trend continued to decline as copper concentrations decreased. In the a* (red) value, the trend had continued to decline. The red value softened, but the green color increased, and the b* (yellow) value showed a decrease in yellow, while an increase in blueness, which resulted in a mixing rate of 18.03Ag 79.75Cu 2.02In with concentration of 97.54% copper and 2.46% indium with a color level most closest to the test piece 18.03Ag The most imported alloy, with the lowest E value of 4.48.