Pressure Effect on Vacancy Formation in Gold

99.999% pure gold wires were resistance heated to 680°C in a gaseous medium at pressures between 400 and 11 000 atmospheres and quenched by turning off the heating current. The temperature decayed exponentially with a half-life of 1.6×${10}^{-2\mathrm{}}$ sec. The logarithm of the quenched-in electric resistance $\Delta R$ decreased linearly with increasing pressure. From the pressure effect on $\Delta R$ an activation volume for vacancy formation at 680°C of $\Delta V_f=(9.16\mathrm{}\pm 0.68)\times {10}^{-24\mathrm{}}{\mathrm{cm}}^3=0.53\mathrm{}\pm 0.04$ atomic volume is derived, assuming that the quenched-in resistivity is due to the formation of single vacancies. In the pressure range investigated, $\Delta V_f$ is apparently independent of the pressure. Using $\Delta V_f$ and Bauerle and Koehler's relationship between resistivity and fractional volume change during recovery, the electric resistivity of vacancies is (1.8±0.4)×${10}^{-6\mathrm{}}$ Ω cm/at.% and the vacancy concentration after quenching from 680°C at room pressure with 1.6×${10}^{-2\mathrm{}}$ sec half-life of the temperature decay is (2.4±0.5)×${10}^{-5\mathrm{}}$. The present data are in good agreement with those reported by DeSorbo from a calorimetric study of quenched foil. The present defect concentration is about 50% of the value extrapolated to 680°C from the data of Simmons and Balluffi, who obtained the vacancy concentration in thermal equilibrium near the melting temperature.