Hydrogen Surface Etching of Molten Silica

Melting experiments with quartz sand were carried out under H2 atmospheres at temperatures between 1700° and 1850°C. Upon quenching, fine-scale, hemispherical, pitted morphologies were noted at the surface of the melts. The degree of uniformity of the resulting features was observed to depend on the temperature of melting. The results are compared with similar reported observations at lower temperatures that are attributed to impurity-based instabilities in the surface tension and evaporation.