Tanimoto Yasuhiro, Nemoto Kimiya
Department of Dental Biomaterials, Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
J Prosthodont. 2006 Nov-Dec;15(6):345-52. doi: 10.1111/j.1532-849X.2006.00133.x.
The purpose of this study was to investigate the effect of sintering temperature on flexural properties of an alumina fiber-reinforced, alumina-based ceramic (alumina-fiber/alumina composite) prepared by a tape casting technique.
The alumina-based ceramic used a matrix consisting of 60 wt% Al(2)O(3) powder and 40 wt% SiO(2)-B(2)O(3) glass powder with the following composition in terms of wt%: 33 SiO(2), 32 B(2)O(3), 20 CaO, and 15 MgO. Prepreg sheets of alumina-fiber/alumina composite in which uniaxial aligned alumina fibers were infiltrated with the alumina-based matrix were fabricated continuously using a tape casting technique employing a doctor blade system. Four sintering temperatures were investigated: 900 degrees C, 1000 degrees C, 1100 degrees C, and 1200 degrees C, all for 4 hours under atmospheric pressure in a furnace. The surface of the alumina-fiber/alumina composite after sintering was observed with a field-emission scanning electron microscope (FE-SEM). A three-point bending test was carried out to measure the flexural strength and modulus of alumina-fiber/alumina composite specimens. In addition, sintered alumina fiber was characterized by X-ray diffraction (XRD).
FE-SEM observation showed that alumina-fiber/alumina composite was confirmed to be densely sintered for all sintering temperatures. Three-point bending measurement revealed that alumina-fiber/alumina composite produced at sintering temperatures of 1100 degrees C and 1200 degrees C exhibit flexural strengths lower than those of alumina-fiber/alumina composite produced at sintering temperatures of 900 degrees C and 1000 degrees C; alumina-fiber/alumina composite produced at sintering temperatures of 1100 degrees C and 1200 degrees C exhibit flexural moduli lower than that of alumina-fiber/alumina composite produced at a sintering temperature of 1000 degrees C. Additional XRD pattern of alumina fiber indicated that with increasing sintering temperature, the crystallographic structure of gamma-alumina transformed to mullite.
There were significant differences in the flexural properties between the alumina-fiber/alumina composite sintered at the four temperatures. This indicates that the choice of optimum sintering temperature is an important factor for successful dental applications of alumina-fiber/alumina composite developed by the tape casting system.
本研究旨在探讨烧结温度对采用流延成型技术制备的氧化铝纤维增强氧化铝基陶瓷（氧化铝纤维/氧化铝复合材料）弯曲性能的影响。
氧化铝基陶瓷使用由60 wt% Al₂O₃粉末和40 wt% SiO₂ - B₂O₃玻璃粉末组成的基体，其重量百分比组成如下：33 SiO₂、32 B₂O₃、20 CaO和15 MgO。采用刮刀系统的流延成型技术连续制备氧化铝纤维/氧化铝复合材料的预浸料片，其中单轴排列的氧化铝纤维被氧化铝基基体渗透。研究了四个烧结温度：900℃、1000℃、1100℃和1200℃，均在大气压力下于炉中烧结4小时。烧结后的氧化铝纤维/氧化铝复合材料表面用场发射扫描电子显微镜（FE - SEM）观察。进行三点弯曲试验以测量氧化铝纤维/氧化铝复合材料试样的弯曲强度和模量。此外，用X射线衍射（XRD）对烧结后的氧化铝纤维进行表征。
FE - SEM观察表明，在所有烧结温度下，氧化铝纤维/氧化铝复合材料均被证实致密烧结。三点弯曲测量显示，在1100℃和1200℃烧结温度下制备的氧化铝纤维/氧化铝复合材料的弯曲强度低于在900℃和1000℃烧结温度下制备的氧化铝纤维/氧化铝复合材料；在1100℃和1200℃烧结温度下制备的氧化铝纤维/氧化铝复合材料的弯曲模量低于在1000℃烧结温度下制备的氧化铝纤维/氧化铝复合材料。氧化铝纤维的额外XRD图谱表明，随着烧结温度的升高，γ - 氧化铝的晶体结构转变为莫来石。
在四个温度下烧结的氧化铝纤维/氧化铝复合材料的弯曲性能存在显著差异。这表明选择最佳烧结温度是通过流延成型系统开发的氧化铝纤维/氧化铝复合材料在牙科应用中取得成功的重要因素。
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