Unleaded transparent vitreous ceramic compositions and articles.

摘要

A composition which represents a new class of unleaded transparent vitreous ceramic which is described as an 'Advanced or Combined Intermediate Oxide Alkali Borosilicate. The composition comprises in combination a specially developed alkali borosilicate and a major addition selected from combinations of the group of traditionally accepted opacifiers, consisting of Zirconium, Tin, and Titanium, the said elements being present in said combination in amounts 0.5 to 43.9 wt% in terms of the Oxide form. The major addition will consist of at least two of said elements. The composition may include minor additions (</= 10wt%) of any other element or elements which do not cause loss of transparency.