abstract |
This invention relates to the manufacture of articles exhibiting the physical properties and internal microstructure of glass-ceramics but which can be formed spontaneously from a glass-forming melt, i.e., the heat treatment of a glass body to cause the crystallization in situ thereof conventional in the production of glass-ceramic articles is not required. More particularly, this invention is concerned with the manufacture of glass-ceramic articles having compositions within the Na2O-MgO-SiO2-F field, wherein a fluormica constitutes the primary crystal phase, which can be formed spontaneously from a molten glass batch. |