Kinetics of reaction of magnesium vapour with silica

Abstract

A technique for controlling and monitoring the pressure of a metal vapour, which employs a high-temperature Knudsen cell in combination with characteristic absorption spectrophotometry, is described. The technique is evaluated by studying the behaviour of magnesium vapour.

As the rate of evolution of magnesium is comparable with its rate of reaction with solids, the latter can be studied by following the pressure against time behaviour of the magnesium. An investigation has been made of the reaction of magnesium with silica and the results are interpreted on the basis of a pre-adsorption on the silica surface, followed by reaction at a lower rate.