Process for producing and product of a machinable crystallized glass having needle-like crystals precipitated therein

摘要

A process for producing a machinable crystallized glass having needle-like crystals precipitated therein, which comprises melting a mixture comprising from 40 to 60 mol % of SiO2, from 6 to 16 mol % of Al2O3, from 6 to 16 mol % of Y2O3 and from 15 to 30 mol % of CaO, and allowing the melt to cool to have fine needle-like crystals of Ca4Y6O(SiO4)6 precipitated.