Formation of Crystal Structure in Dielectric Baal2si2o8-Based Materials Depending on Preparation Conditions

Crystal structure formation of BaAl2Si2O8 known as polymorphic compound is investigated in present work depending on conditions of preparation. Characteristics of ceramics have been studied for different modifications of crystal structure. Additional technologic operations (grinding with following heat treatment) have been found to result in polymorphic transformation. Dielectric properties of BaAl2Si2O8 ceramics have been studied for hexagonal, monoclinic crystal structure modifications as well as for that based on phase mixture. It has been shown that the sintering of ceramic material based on the monoclinic crystal structure modification of BaAl2Si2O8 takes place in temperature diapason of 1300-1350 degrees C. Sintering of material with the hexagonal crystal structure modification occurs in temperature diapason of 1450-1500 degrees C. Ceramics materials based on compound BaAl2Si2O8 are found to have low porosity, high Q-factor and dielectric characteristics, allowing use of these ceramic materials for production of resonators and other microwave equipments.