Using short-time sintering to initiate the crystal structure of microwave ceramics in the BaO-TiO 2 , MgO-TiO 2 and ZrO 2 -TiO 2 systems

Abstract In this work, a cost-effective approach to determining the optimal composition of the charges based on the prediction of the crystal structure was tested. It consists of short-term solid-phase sintering with isothermal holding at a temperature of 1300 °C for 5 min to initiate the formation of the target crystalline structures of microwave dielectric ceramic materials from the BaO-TiO 2 , MgO-TiO 2 , and ZrO 2 -TiO 2 systems. Analysis of the crystalline structure, morphology, and composition of the ceramic samples obtained in this study using short-term solid-phase sintering showed that, along with the initial oxides, they contain crystalline phases preferred for microwave dielectric ceramics, such as BaTiO 3 , BaTi 4 O 9 , Ba 2 Ti 9 O 20 , MgTiO 3 , MgTi 2 O 5 , and ZrTiO 4 . The morphology and crystal sizes of these samples, measured in tens of nanometers, along with low microstrains and dislocation densities, are similar to those obtained, according to literature data, for functional microwave dielectrics of the same systems under long-term sintering conditions. However, all ceramic samples obtained in this study using short-term sintering contained amorphous carbon impurities as a result of incomplete removal of the decomposition products of the organic binder, which prevented the achievement of ideal dielectric properties. The best example of ceramics produced by the method of short-term solid-phase sintering has a permittivity of 19.4, a quality factor of 23.8, and a loss tangent of 0.042 at a frequency of 100 kHz. Thus, the proposed short-term sintering method proved to be suitable for use as an experimental tool for predicting the phase composition of ceramics in a nonequilibrium state.