Porous Structure and Exploitation Properties of Nanostructured MgO-Al2O3 Ceramics Technologically Modified by Time-Temperature Regimes

Porous structure and exploitation properties in nanostructured MgO-Al2O3 ceramics prepared at 1300 °C and 1400 °C for 5 and 9 h were studied. In ceramics sintered at higher temperatures and durations there is an increase in the area of contact between grains, and also the open porosity is formed, which leads to an increase in the effective adsorption of humidity. A branched pore structure is required for effective sorption processes. Humidity sensitivity of ceramics and the minimum hysteresis in adsorption-desorption cycles are due to the three-dimensional distribution of pores in size and insignificant number of additional phases. The loss of humidity sensitivity in ceramics sintered at higher temperatures and durations is related with evolution of porous structure of ceramics. The degradation transformations in the investigated ceramic lead to the improvement of their humidity sensitivity.