Crystallization and properties of glass-ceramics of the K2O-BaO-B2O3-Al2O3-TiO2 system

Crystallization behavior and properties of glass-ceramics with content (mol%) of: K2O = 3-25, BaO = 3-27, B2O3 = 8-26, Al2O3 = 13-18, and TiO2 = 31-47 were studied. The relation between the initial composition and the formation of the crystalline phases was analyzed. When increasing [Al2O3] and [BaO], was increased the temperature of crystallization; likewise, different barium potassium titanates appeared with [BaO] = 3-13 (Group 1), whereas, different barium titanates were obtained with [BaO] = 13-30 (Group 2). The influence of chemical composition on the properties of density, mechanical strength, chemical durability and dielectric properties (dielectric constant and dielectric losses), was discussed. Glass-ceramics with high mechanical resistance in the range of 189-480 MPa and permittivity values between 4.03 and 25.31, and dielectric losses <2 x 10(-4) at 1MHz were produced.