Abstract:

Abstract： Objective To explore the feasibility for producing a machinable alumina bulk by means of the two-step calcination together with the properly controlled firing cycle set and thus to provide experimental basis for its clinical application. Methods Ultrafine α-alumina powder was firstly produced by two-step calcination， and machinable porous alumina bulks of pure alumina powder and of mixing powder added with MgO were separately formed through compression molding and temperature-controlled firing. The bulks were then coated with VTIA In-Ceram glass-infiltrated powder was burned to produce glass-infiltrated composites. Scanning electron microscopy and X-ray diffraction （XRD） examination were adopted to analyze the microstructure and phase composition of the composites. Results The alumina bulk with MgO-added showed a continuous infiltrated porous skeleton by the scanning electron microscopy. The infiltrated composite was compact ceramic complex. XRD indicated the major crystal phase wasα-alumina. Conclusion Ultrafine grain-sized alumina powder can be made from ammonium aluminum sulfate and infiltrated porous alumina bulk can be produced with the properly controlled firing cycle set. The process is simple and low-cost. The product with further improvement can be expected for clinical application.

Key words: In-ceram technology, alumina bulk, glass-infiltrated properties, scanning electron microscopy

摘要：

目的 探讨通过硫酸铝铵两步煅烧法及控制烧结工艺制作可切削氧化铝基体的可行性，为临床应用提供实验依据。方法 采用硫酸铝铵两步煅烧法制备α-氧化铝粉体。将α-氧化铝粉体和含氧化镁添加剂的氧化铝粉体分别放入模具中模压成型，然后进行控温烧结形成可切削的多孔氧化铝基体。在多孔氧化铝基体的上表面涂塑VTIA In-Ceram玻璃渗透粉体，然后烧结制备氧化铝玻璃渗透陶瓷复合体。采用扫描电镜并结合X线衍射分析分别对材料的微观形貌和物相组成进行分析。结果 扫描电镜可见含氧化镁添加剂的氧化铝基体为连续多孔立体网状结构，开孔结构分布均匀；渗透复合体为致密的陶瓷复合体；X线衍射分析表明主晶相为α-Al2O3。结论 硫酸铝铵经过两步煅烧工艺能够生成α-氧化铝粉体，通过控制烧结工艺能够制得渗透性能良好的可切削多孔氧化铝渗透基体。该烧结工艺过程简单、价格低廉，产品进一步完善有望临床使用并实现产业化。

关键词: In-ceram技术, 氧化铝基体, 玻璃渗透性能, 扫描电镜