Sodium fluormica glass-ceramics

摘要

A family of synthetic mica glass-ceramic compositions is disclosed based on a modified sodium fluoromontmorillonoid stoichiometry. These are spontaneously crystallizable glass-ceramics which are composed of 50-62% SiO2, 20-28% MgO, 5-15% Na2O, and 8-13% F. The method comprises supplying excess fluoride during melting to devise a synthetic mica having sodium fluoromontmorillonoid or a solid solution on the talc axis as the dominant crystal phase.