Preparation and properties of porous ceramics based on alumomagnesium spinel and zirconium dioxide

Resumo

The foundations of the technology for the preparation of porous nanoceramics based on alumomagnesium spinel (MgAl₂O₄) and zirconium dioxide stabilized in the tetragonal structure (t-ZrO₂) with an open porosity of >40% are developed. It is revealed that the cocrystallization of salt solutions with subsequent mechanochemical activation of crystallohydrates can be used for the production of nanosized MgAl₂O₄ and t-ZrO₂ powder precursors (<20 nm). A possible way to control the open porosity and the pore size by choosing the optimal sintering temperature and the kind and the amount of pore-forming additives is shown. The width of the pore size distribution increases with increasing volume fraction of the blowing agent in the initial powder. Nanoporous ceramic materials with pores 25–100 nm in size for MgAl₂O₄ and 100–300 nm for t-ZrO₂ are produced. The technological scheme for applying an α-Al₂O₃ membrane layer on a t-ZrO₂ porous matrix is developed.