Porous mullite ceramics fabricated by co-pyrolysis alumina powders filled silicone resin

Abstract

Nanoporous mullite ceramics were fabricated by pyrolysis of micron alumina powders filled with silicone resin. The mixture of silicone resin and micron c-Al 2 O 3 began transforming to mullite at 1250uC in air, and could be entirely transformed to mullite when the pyrolysis temperature exceeded 1300uC. The effect of shaping pressure on microstructure and mechanical property of the porous mullite ceramics was investigated. The experimental results showed that the porosity and flexural strength can be easily tuned by changing shaping pressure. Both of the open porosity and average pores size of the obtained samples decreased at elevated shaping pressure. With a shaping pressure of 65 MPa, nanoporous mullite ceramics with an average pore size of 32 nm can be obtained, showing 23?5% in open porosity and 50 MPa in flexural strength. Interestingly, the microstructure of porous mullite ceramics consisted of loose region and dense region for the most possible reason that the Al 2 O 3 powders were un-homogeneously distributed in silicone resin.

Effects of TiO2, B2O3, and SiO2 on formation of TiB2/mullite composites by thermite-based combustion synthesis

“…Fabrication routes for mullite ceramics and composites include the sol-gel method [8,9], molten salt synthesis [10], co-precipitation [11], co-pyrolysis [12], reaction sintering [13][14][15], spark plasma sintering (SPS) [16], suspension combustion process [17], etc. Kaolinite and alumina were often employed in reaction sintering to produce mullite because of cheap raw materials and simple procedures [13].…”