Highly Transparent BaAl4O7 Polycrystalline Ceramic Obtained by Full Crystallization from Glass

Fully dense, transparent polycrystalline ceramics are simply obtained by direct and complete crystallization from glass. This is demonstrated for the previously unreported composition, BaAl4O7, which exhibits two orthorhombic polymorphs with micrometer grain size, both optically transparent in the visible range. This innovative synthetic route to transparent polycrystalline ceramics should facilitate the discovery of new cost-effective chemical methods for transparent ceramic applications.