背景:在临床应用中,全瓷修复可解决以往材料的美观与安全等方面的问题而被越来越广泛的接受,尤其是高强度高韧性的氧化锆全瓷材料倍受关注.目的:分析摩尔分数为3%氧化钇稳定的四方多晶氧化锆(3Y-TZP)的烧结性能、力学性能及微观结构.设计、时间及地点:材料学表征,观察实验,于2007-02/2009-05在解放军第四军医大学口腔医学院修复实验室设计实施完成.材料:纳米3Y-TZP粉体(粒度约50 nm)由上海双鼎纳米材料有限公司提供.方法:纳米3Y-TZP粉末与浓度7%聚乙烯醇混合,搅拌均匀后造粒,双向干压成型,制备圆盘及长条状试件,常压烧结.其中圆形试样用于烧结性能测试,长条形试样用于力学性能及微观结构测试.主要观察指标:Archimedes法测试烧结性能,并检测三点抗弯强度、断裂韧性;扫描电镜观察断面形貌;X射线衍射分析晶相组成,比较表面与断面的四方相含量.结果:纳米3Y-TZP在1 500℃烧成,结构致密,三点抗弯强度(921.7±44.2)Mpa;断裂韧性(10.2±1.6)Mpa·m~(1/2).微观形貌示烧结后结构均匀致密,缺陷少,晶粒细小,粒径约0.3μm.X射线衍射分析材料表面为四方相,无单斜相衍射峰;断面四方相81%,单斜相19%.结论:纳米3Y-TZP材料低温烧结,颜色美观,微观结构致密均匀,强韧性好,适宜做牙科全瓷材料.%BACKGROUND: In clinical application, all-ceramic restorations have been widely used because of favorable cosmetic effect and safety, especially zirconia all-ceramic materials with high intensity and toughness. OBJECTIVE: To analyze the sintering and mechanical properties and microstructure of nano-powder 3 mol % yttria stabilized tetragonal zirconia polycrystal (3Y-TZP). DESIGN, TIME AND SETTING: Material characteristics observation. The experiment was performed at the Laboratory of Prosthodontics, Hospital of Stomatology, Fourth Military Medical University of Chinese PLA from February 2007 to May 2009. MATERIALS: 3Y-TZP (50 nm) was provided by Shanghai Shuangding Nanomaterial. METHODS: Nano-powder of 3Y-TZP was mixed with 7% poly vinyl alcohol, dry-pressed, prepared into disc and strip samples and sintered at certain temperature. The disc sample was used for sintering properties measurement, and strip sample was used for mechanical and microstructural detections. MAIN OUTCOME MEASURES: Sintering properties, three-point bending strength and fracture toughness were measured by Archimedes method. Microstructure and crystalline phase composition were analyzed with scanning electron microscopy and X-ray diffraction. RESULTS: 3Y-TZP sintering was finished at 1 500 V. The flexural strength was (921,7 44.2) MPa, fracture toughness was (10.2±1.6)MPa·m~(1/2). Microstructure of sample sintered by nano-sized powder was even and condensed, witht-m phase transformation when fractured. The tetragonal phase of cross section was 81 % and monoclinic phase was 19%. CONCLUSION: Nano-powder 3Y-TZP sintered by low temperature has dense microstructure and high toughness. It is a promising esthetic all-ceramic dental material.
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