Properties of a Mullite-Zirconium Ceramic Sintered by the Traditional Method from Powders Obtained During Combustion

Results are presented from a study of the growth of the crystalline phases, the size distribution of the pores, and the size distribution of the particles that make up the powders. The powders were obtained by a water-based combustion method with the use of a mix containing solutions of nitrates of metals, SiO2 (aerosil), an oxidant, and different fuels. The article reports results obtained from the formation of the crystalline phases and data on the pore-size distribution, apparent density, degree of sintering, and physico-mechanical properties of specimens sintered from the powders by the conventional method in the range 1300 – 1500°C with and without the use of a clay addition. The powders formed by the combustion of carbamide and limonic acid are characterized by developed mullitization and crystallization of the tetragonal phase of ZrO2, the formation of coarse and relatively coarse pores, and the formation of fine and moderate-sized particles. The specimens sintered from such powders in the range 1300 – 1500°C with a clay addition are characterized by developed crystallization of the phases and maximum values for apparent density, degree of sintering, and the indices of the physico-mechanical properties. These results stand in contrast to the results obtained for the specimens sintered from similar powders without clay and specimens sintered from clay and powders obtained by the combustion of glucose and saccharose.