Reduction of Silica in a Hydrogen Discharge

Abstract

IT is well known that silica can be reduced by carbon at temperatures of the order of 1,600°–2,000° C, to yield the volatile silicon monoxide. Among other reported methods for reducing silica the use of silicon at 1,000°–1,300° C at pressures of 10⁻⁴–10⁻⁵ mm¹, or at 1,600° C and atmospheric pressure², appears to be effective. The existence of the SiO molecule in vapour form is well established from spectroscopic data, and when the vapour condenses the deposits formed consist of mixtures, dispersions or possibly solutions of silicon and SiO₂. Such deposits, because they are readily obtained as thin, hard, transparent layers which are highly resistant to chemical attack, have been used as coatings for optical surfaces, in electrical capacitors, solar cells, etc.