High-Rate Microwave Sintering of Ceramics on the Basis of Barium and Strontium Titanates

Using the method of sintering by microwave heating at a rate of 10-100 degrees C/min to a temperature of 1250 degrees C without isothermal hold, we obtain ceramic samples with the composition Ba0.75Sr0.25TiO3. The experiments are performed on a gyrotron complex for the high-temperature microwave treatment of materials, which is operated at a frequency of 24 GHz with a maximum power of 5 kW. The features of the formation of a solid solution in the sintered samples are analyzed. The dependence of the intensity of recrystallization growth of grains on the microwave-heating rate during the sintering is demonstrated. The permittivity of the samples obtained by microwave sintering with heating rates of 10 and 30 degrees C/min amount to 3600-4400 in the frequency range 25Hz-3MHz at room temperature.