Processing of Super High Strength Neat Ner Shape Ceramics, Using High-speed Centrifugal Compaction and Micro Wave Sintering.

采用高速离心压实和微波烧结加工超高强度整齐形状陶瓷。

• 批准号: 08555036
• 负责人: KUROKI Hidenori
• 金额: $ 8.19万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08555036/
• 关键词: Centrifugal compaction; High strength; Alumina; Sub micron; Net shape; Micro wave sintering; Bending strength; 遠心形成

A high purity alumina made by high speed centrifugal compacion (AC) invented by Tashima et al. has many superiority over the conventional compacton, including low sintering temperature, fine and homogeneous microstructute, and high mechanical properties. In the study, we applied new method of sintering on the AC,a 28MHz microwave sintering proposed by Saji et al., in order to improve mechanical properties.The reslts were following.1.Appropriate setting position of the specimen in the furnace and appropriate heating program were determined. Using the determined condition, it was enable to sinter the green compacts in greater heating rate compared to the conventional sintering (ten times higher) without inhomogeneity of microstructure.2.It was found that the microwave sintering in vacuum is suitable for the AC,because of the direct reaction of the microwave on the specimen. The specimen sintered by this method showed superio properties.3.Applying microwave sintering in vacuum, the green compacts were enable to sinter at about 50K lower temperature than the conventional sintering. Furthermore, those compacts showed finer grain size distribution comparing to conventionally sintered compacts which had the same density.4.The compacts made by microwave sintering in bacuum shows 4-point bending strength of 1140MPa (converted to 3-point vending strength of 1360MPa). This is the best record of the alumina ceramics ever reported. Besides, the specimens showed a vickers hardness of about 50MPa higher than the conventionally sintered specimens.5.As for the fracture toughness, there was not an obvious difference in the value between differently sintered specimens.6.By the results, we concluded that the processing of the processing of super high strength alumina ceramics were established, using both the centrifugal compaction and the microwave sintering in vacuum.

一种由Tashima等人发明的高速离心压实(AC)法制备高纯氧化铝。与传统压坯相比，具有烧结温度低、组织细小均匀、力学性能高等优点。为了提高材料的力学性能，本文采用了Saji等人提出的28 MHz微波烧结新方法，研究结果如下：1.确定了合适的样品放置位置和合适的加热程序。在所确定的条件下，与常规烧结相比(高出10倍)，可以在更高的升温速度下烧结生坯，且组织不均匀。2.由于微波直接作用于样品，因此真空微波烧结适合于交流烧结。3.真空微波烧结可使坯体在比常规烧结温度低约50K的条件下烧结。此外，与相同密度的常规烧结压坯相比，这些压坯具有更细小的粒度分布。4.在真空中微波烧结的压坯的四点弯曲强度为1140 Mpa(换算为三点抗折强度为1360 Mpa)。这是迄今为止报道的氧化铝陶瓷的最好记录。此外，超高强氧化铝陶瓷的维氏硬度比常规烧结的高出约50 Mpa。5.在断裂韧性方面，不同烧结的样品之间没有明显的差异。6.根据实验结果，确定了采用真空微波烧结和离心压实相结合的超高强氧化铝陶瓷的加工工艺。