The interaction of oxygen and hot gold. Part 1

Abstract

The behaviour of hot gold filaments, in vacuum and in oxygen at pressures of a few microns of mercury, has been studied. Two main effects were observed-the disappearance of gaseous oxygen and a rate of evaporation of gold considerably greater in oxygen than in vacuum.The rate of disappearance of oxygen ( E ) depended on the purity of the gold, but the amount which disappeared was too large to be explained as oxidation of impurities in the metal. The disappearance is attributed to an impurity-catalyzed conversion of oxygen molecules from the ground to the metastable lAg state, the 0; attacking the walls of the reaction vessel. E decreased as the walls became protected by a film of evaporated gold. The enhanced rate of evaporation of gold in 0 2 is attributed to the removal of an inhibiting surface film of impurity. In N2, E was zero and there was no enhanced evaporation of gold.The activation of molecular oxygen is discussed in appendix 1 by D. M. Gilbey. Appendix 2 by D. Clark reports on the structure of the evaporated gold deposits.

Volta Potential Studies of the Aging of Gold Surfaces1

“…Both the quantity of oxygen taken up and the rate of adsorption increased with increasing temperature. Recently, Carpenter, Clark,Main,and Dickson,4 studying changes of the pressure of oxygen in contact with 883°g old surfaces of variable purity, concluded that metallic impurities in the gold are oxidized, suggesting that gold surfaces are contaminated by surface films of metallic impurities from the gold. Shishakov,6 from electron diffraction studies at room temperature, concluded that gold heated at 500°in oxygen at atmospheric pressure is coated with gold peroxide.…”