JIAO Chunrong 1, 2, CHEN Daming 2, TONG Jianfeng 1, 2, HUANG Hao 2
(1. National Key Laboratory of Advanced Composites, Beijing Institute of Aeronautical Materials, Beijing 100095, China; 2. Aviation Industry Corporation of China Composites Center, Beijing 100095, China)
Abstract: Porous alumina ceramics were fabricated by low-cost foaming and gel-casting technology with water-soluble epoxy and polyamine resin system. The rheological properties of the slurries, the foaming, the coagulation and the sintering process were studied. Also,the microstructure, the bending strength and the dielectric constant were investigated. Results show that the complex properties of alumina ceramic slurry is best when the solid content is 50vol.% and the dispersant content is 0.25wt.% of the alumina powders. The water-soluble epoxy and the polyamine resin amount to 6vol.% and 2.4vol.% of the slurry respectively. When the foaming agent content is from 2vol.% to 6vol.% of the slurry, the foaming time is 1 hour, the coagulation time is 3 hours at 40 ℃, porous alumina ceramics gels with different porosities could be obtained. After demoulding, drying, and sintering at 1580 ℃ for 3 hours, the porous alumina ceramics were prepared with the porosity between 60.8-43.4%, the bending strength of 32-55 MPa, and the dielectric constant of 2.8-4.4. Both their bending strength and dielectric constant linearly vary with their porosity.
Key words: porous alumina ceramics; water-soluble epoxy; foaming and gel-casting