Fabrication of porous alumina ceramics having cell windows with controlled size by PMMA template method

Highly porous alumina compacts have been prepared by filling alumina slurry into opening of a specially designed template block prepared by cross-linked (cl-) polymethylmethacrylate (PMMA) microspheres (mean particle size: 98.6 μm) under reduced pressure, followed by firing to remove the template and then sintering at 1600 °C. The template blocks were prepared by utilizing cl-PMMA and acetone solution dissolving noncrosslinked (Ncl-) PMMA as an adhesive to make partial connection among the cl-PMMA microspheres. Furthermore, the effects of the addition of other chemicals (two types of triblockcopolymers and a nonionic surfactant) to the Ncl-PMMA adhesive solution were tested to improve the wettability of the solution to cl-PMMA and then to control the cell windows among the cl-PMMA-originated cells after the firing. By employing the template block, prepared with the adhesive solution containing an appropriate amount of triblockcopolymer, a highly porous alumina compact having an open porosity of 77.2%, a mean cell window diameter of 28.8 μm, and strong alumina skeleton could be fabricated.