The effect of temperature and steam pressure on the vaporization and corrosion of silica was studied by measuring weight loss as a function of time. The reaction rate increased exponentially with temperature up to 1200°, with a maximum rate of reaction at ∼1350°C. Above this temperature the rate abruptly decreased with increasing temperature. The pressure dependence of the reaction was approximately linear. The activation energy was ∼25 kcal/mol for the reaction at 0.84 and 14.5 atm steam. Copyright © 1979, Wiley Blackwell. All rights reserved