Sintering of Zinc Oxide

Sintering studies have been conducted with single crystal spheres of zinc oxide in air at total pressures of 10⁻³ to 1.0 atm over the range 1050° to 1250°C. Quantitative observations were made on the rate of growth of a neck between the spheres. No change in the distance between the geometrical centers of the spheres was observed. An analysis of the kinetic data shows that sintering was predominantly achieved by distillation through the surrounding gas phase. At 1150° the rate of welding was inversely influenced by the total pressure when the latter was changed from 0.003 to 0.75 atm. No conclusion could be reached on the effect of the oxygen partial pressure at constant total pressure. A brief summary of the various sintering mechanisms of zinc oxide from 700° to 1250°C is presented.