GI-Ⅱ型渗透陶瓷中氧化铝坯体和烧结体的孔隙分析

Characterization of Alumina Adobe and Sintered Body of GI-Ⅱ Infiltrated Ceramic

目的 研究 GI- 型渗透陶瓷氧化铝坯体和烧结体的孔隙特征 ,分析其氧化铝多孔结构的形成机理和在渗透陶瓷增强补韧中的作用。方法 用 BI- XDC粒度分析仪分析氧化铝粉体粒度的质量组成 ,压汞法测试氧化铝坯体和 112 5℃烧结的氧化铝烧结体的开孔孔隙分布特征 ,扫描电镜观察氧化铝烧结前后的微观结构。结果 氧化铝粉体细颗粒分布在 0 .0 9～ 0 .1μm,0 .2～ 0 .5 μm,粗颗粒主要分布在 1.5～ 4.5 μm,在质量上以粗颗粒为主。氧化铝坯体中孔隙在烧结后增大。坯体中孔隙半径集中在 0 .2 5 31μm,烧结体中孔隙半径集中在 0 .30 81μm;平均半径由 0 .0 95 6 μm变为 0 .110 2 μm。扫描电镜观察烧结后的氧化铝中的小颗粒相互部分融合 ,而大颗粒无此现象。结论 氧化铝粒度组成有利于形成多孔可渗透氧化铝结构。这种多孔结构既是 GI- 型渗透陶瓷的形态骨架 ,也是力学骨架 ,是提高渗透陶瓷复合体力学性能的关键。

Objective This study was conducted to elucidate the mechanism of formation of porous structure by investigating the porosity of the alumina adobe and sintered body of GI Ⅱ Infiltrate Ceramic, and its role in strengthening and toughening this kind of ceramic composite. Methods The alumina powder size mass distribution was obtained by BI XDC powder size analysis device; the open pore parameters of alumina adobe and sintered body were analyzed using the mercury pressure method. Their fracture surfaces were observed under scanning electronic microscope. Results Fine powder had two main size groups of 0.09 0.1μm and 0 2 0 5μm, respectively, and coarse powder, with size between 1 5 to 4.5μm, occupied the majority of powder mass. Alumina adobe's pores became larger after sintering. The median pore radii of adobe and sintered body were 0 2531μm and 0.3081μm, respectively; the average pore radii changed from 0.0956μm to 0.1102μm. Under scanning electronic microscope, fine alumina powders were fused partially together and their surfaces were blunted, but coarse powders did not show such phenomena. Conclusion The alumina size distribution contributes to the formation of porous structure of alumina sintered body. This porous structure is not only the shape skeleton but also the mechanical skeleton of GI Ⅱ Infiltrated Ceramic. It plays an important role in raising the mechanical properties of this kind of ceramic composite.