DISTINCTIVE FEATURES OF THE CORROSION OF BASALT FIBRES IN ALKALI MEDIA AT ELEVATED TEMPERATURES

摘要

This paper describes the distinctive features of mineral (basalt) continuous fibre corrosion in concentrated alkaline solutions at high temperature. Precipitates with different chemical composition and form were discovered on the surface of basalt fibre after etching in boiling NaOH solutions. Based on X-ray microanalysis data it is possible to assume that mentioned precipitates were formed during fibre formation from the melt. Precipitates probably have an influence upon mechanical and thermal resistance of basalt continuous fibres. Detailed investigation of "soda paradox" for basalt fibres shows the concentration dependence of mentioned phenomenon. Probably this phenomenon is inherent in basalt as mineral raw material, and the mechanism of basalt fibres destruction under the influence of alkalis differs essentially from the mechanisms taken place for silicate glasses. Such difference opens additional opportunities to improve alkaline resistance of basalt continuous fibres.