纳米氧化锆的含量对纳米氧化锆增韧氧化铝陶瓷力学性能和显微结构的影响

Influence on Mechanical Properties and Microstructure of Nano-zirconia Toughened Alumina Ceramics with Nano-zirconia Content

目的探讨纳米氧化锆的含量对纳米氧化锆增韧氧化铝陶瓷力学性能和显微结构的影响。方法将纳米氧化锆、氧化铝、复合添加剂等粉料与一定比例的醇—水混合后,球磨制备浆液,采用离心渗透注浆法成坯,在1450℃下烧结8h。烧结体打磨抛光后,测试其物理性能和力学性能。通过扫描电镜观察烧结体表面和断面的微观结构。结果不同实验组的三点抗弯曲强度、维氏硬度的差异均有统计学意义(P<0.01);20%氧化锆组的断裂韧性与另外两组差异有统计学意义(P<0.05),10%氧化锆组和30%氧化锆组间的断裂韧性差异没有统计学意义(P<0.05)。当纳米氧化锆含量为20%时,其力学性能显著高于10%及30%组,三点抗弯曲强度为(433±19)MPa,断裂韧性达(7.50±0.56)MPa·m1/2。显微结构观察到内晶—晶界复合型结构、晶间及穿晶断裂。结论内晶—晶界复合型结构具有强烈的增韧效果,可提高陶瓷的强度和韧性。纳米氧化锆含量为20%时,具有较好的增韧效果,适合口腔修复材料。

Objective To investigate the mechanical properties and microstructure of nano-zirconia toughened alumina ceramics with variety of nano-zirconia content in centrifugal infiltrate casting processing of dental all-ceramic. Methods Composite powder with different ethanol-water ratio, obtained serosity from ball milling and centrifugal infiltrate cast processing of green, then sintered at 1 450℃for 8 h. The physical and mechanical properties of the sintered sample after milling and polishing were tested. Microstructures of the surface and fracture of the sintered sample were investigated by SEM. Results The experimental results showed that there had statistical significience （P〈0.01） on static three-point flexure strength and Vickers Hardness in three kinds of different nano-zirconia content sintered sample. Fracture toughness of 20% group was different from other two groups, while 10% group had not difference from 30% group （P〈0.05）. The mechanical properties of this ceramic with 20% nano-zirconia was the best of the three, the static three-point flexure strength was（433±19）MPa and fracture toughness was（7.50＋0.56）MPa·m^1/2. The intra/inter structure, fracture of intragranular and intergranular on the surface and fracture of sintered sample in microstrucre was also found. Conclusion Intra/inter structure has strengthen toughness in ceramics. It has better toughness with 20% nano-zireonia, is suitable dental all-ceramic restoratives.