【摘要】 目的 :研究GI_Ⅱ型渗透陶瓷氧化铝粉体和坯体的特征 ,分析其形成氧化铝多孔结构的机制。方法 :X衍射分析氧化铝粉体的晶型 ,粒度分析仪测试其粒度组成 ,扫描电镜观察坯体的微观结构。结果 :氧化铝晶体是结构最紧密、最稳定的纯α型氧化铝晶型。氧化铝粉体中小于 0 5 μm的细颗粒占 9wt% ,粗颗粒集中在 1 5～ 3 5 μm ,占75wt%。扫描电镜观察坯体断面发现许多细小的颗粒均匀地附着在大颗粒表面 ,大小颗粒分散均匀 ,堆积较为密实。结论 :氧化铝的晶型、粒度分布、颗粒分散 ,有利于形成多孔可渗透氧化铝骨架 ,是GI_Ⅱ型渗透陶瓷预制体的材料基础 ,也是复合体强度提高的关键更多还原

【Abstract】 Objective:This investigation was to analyze the mechanism of formation of porous structure by studying some characteristics of the alumina powder used for GI_ⅡInfiltrate Ceramic.Methods: The alumina powder crystal type was analyzed with X_diffractometer, and its size distribution was obtained by powder size analysis device, and fracture surface of alumina adobe was observed under scanning electronic microscope.Results: Alumina crystals were purely α type, with firmest structure and best stability. Fine powder whose size was smaller than 0 5 μm occupied 9 wt% (mass) and, coarse powder with sizes between 1 to 3 5 μm occupied 75wt% (mass). The SEM graphs of adobe showed that fine powders were attached to the surface of coarse powders, dispersed evenly, and alumina powders contacted each other firmly.Conclusion: The crystal type, size distribution and even dispersion of the studied alumina powder contributed to the formation of porous structure of alumina sintered body (preform), which was the material prerequisite in forming porous preform and one of the key factors to the rise of strength of GI_Ⅱ Infiltrated Ceramic.\;更多还原