Influence of alumina on the properties of continuous basalt fibers

Abstract

We study the influence of alumina percentage on fundamental properties (structure and crystallization) and applied properties (temperature range of manufacturing and strength) of basalt glasses and continuous basalt fibers (CBFs) on their base. Crystallization of high-alumina glasses and CBFs occurs in three steps. First, magnetite crystallizes, serving as nuclei for subsequent crystallization of augite mineral. Above 900°C, anorthite is the major crystallization product. For low-alumina fibers, augite is the major crystallization product. Fibers and glasses having high alumina percentages have the highest resistance to crystallization. IR spectroscopy showed that the structural connectivity of glasses and fibers increases with increasing alumina percentage. The breaking strength of fibers varies within 1.7–2.5 GPa, increasing with Al2O3 percentage.