超塑性高温发泡制备闭孔多孔Al2O3基陶瓷

分别以纳米和亚微米Al2O3粉末为原料，MgO为掺杂剂，SiC为高温发泡剂，利用Al2O3基陶瓷具有超塑性变形能力的特点，制备了闭孔多孔Al2O3基陶瓷.研究了不同粒径Al2O3粉末和不同MgO含量对Al2O3基多孔陶瓷开口气孔率、闭口气孔率及微观结构的影响，考察了Al2O3基多孔陶瓷的物相组成，探讨了闭口气孔在Al2O3基多孔陶瓷烧结过程中的形成机理.研究结果表明，以纳米Al2O3粉末制备的Al2O3基多孔陶瓷具有更低的开口气孔率，仅为13%，而闭口气孔率可达132%，且其闭孔孔径尺寸约为1~2μm.坯体中MgO与Al2O3反应完全，多孔陶瓷的物相组成仅为Al2O3和MgAl2O4.

Fabrication of Al2O3-Based Porous Ceramic with Closed Pores by Superplastic High-Temperature Foaming Method

Al2O3 based porous ceramic with closed pores was fabricated utilizing the superplastic deformation properties of Al2O3 based ceramics with nano and submicron Al2O3 powder as raw materials， MgO as the dopant and SiC as the high temperature foaming agent. The effects of different particle size of Al2O3 and different amounts of MgO on the apparent porosity， closed porosity and microstructure of Al2O3 based porous ceramic were studied. The phase composition of Al2O3 based porous ceramic was also investigated， and the mechanism of forming closed pores in the sintering process of Al2O3 based porous ceramics was discussed. The results indicated that the apparent porosity of Al2O3 based porous ceramics fabricated with nano Al2O3 powder was lower than that formed with submicron Al2O3. The apparent and closed porosity were 13% and 132%， respectively， and the diameter of the closed pores was about 1~2μm. The phases in the porous ceramic were Al2O3 and MgAl2O4， which generated by the completely reaction between Al2O3 and MgO in the billet.