Chemically Strengthened Low Crystallinity Black Glass-Ceramics With High Liquidus Viscosities

Strong, black materials are needed for electronic device backs and appliance facings. While glass-ceramics have good strength and toughness, their liquidus viscosity is too low to enable economical forming of these devices by the fusion or slot draw methods. Thus, a new class of low crystallinity glass-ceramics with 10-20nm crystallites in the Fe2O3-TiO2-MgO system was invented. These materials were formed into transparent glasses and then heat treated to make black opaque glass-ceramics. These fusion formable glass-ceramics had strengths exceeding the best commercially available glasses after ion exchange. This work provides a new class of low crystallinity fusion formable glass-ceramics with high strength.