A resistometric study of order-hardening in dental gold alloys

The ordering process in gold-copper-silver dental alloys was studied by means of isochoronal and isothermal resistivity measurement. Because the stable existing temperature range of orthorhombic superlattice was unexpectedly extended to lower temperature by the addition of silver to gold-copper binary alloy, the ordering velocity in these alloys are considerably slower than that of binary stoichiometric AuCu alloy. Activation energy, the order of the reaction, and rate constant for growing process were established. The difference in growing mechanisms depending on gold concentration was deduced from the kinetics data.