Amalgamation reaction on mercury-plated dental alloy (Ag3Sn)

The reaction between liquid mercury and Ag3Sn was studied at room temperature using a new type of specimen; i.e. bulk Ag3Sn electroplated with mercury. The surface morphology of the specimen and the phases formed on the Ag3Sn substrate were investigated by various techniques including optical microscopy, electron (scanning) microscopy, electron microprobe analysis, and electron diffraction. It was found that the mode of formation and type of crystalline phase appearing on the Ag3Sn specimen depended on the amount of mercury available. When the amount of mercury exceeded a certain quantity (about 1 mg/cm2) only the gamma1 and gamma2 phases were formed. On the other hand, when the amount of mercury was reduced below a certain low value (less than 0.3 mg/cm2), another silver-mercury phase, beta1, formed as tiny "liquid-like" drops. The experimental technique employed in the present investigation has proved to be an excellent method for studying the reaction between liquid mercury and metal specimens. This new procedure may be employed to evaluate the amalgamation ability of potential new alloy systems.