固相含量和烧结制度对凝胶注模成型牙科ZTA陶瓷的影响

Effects of Solid Content and Sintering System on the Gel-casting ZTA Basal Crowns

目的:探讨采用凝胶注模成型纳米ZTA复合陶瓷粉体,比较不同固相含量素坯在不同半烧结制度下对ZTA陶瓷性能的影响。方法:将微米级氧化铝和纳米级氧化锆按质量比4∶1配置,添加烧结助剂氧化镁、氧化钛,制备ZTA复合粉体。去离子水中加入单体与交联剂制成预混液,加入分散剂,分别制备50%、53%、55%、57%固相含量的浆料,凝胶注模成型后,分别于1150℃、1250℃、1350℃、1450℃温度下烧结,测定性能,SEM观察断面。结果:相同固相含量的试件,三点抗弯强度、线性收缩率、相对密度均随烧结温度升高而升高。同种温度下,试件线性收缩率随固相含量提高而降低,相对密度升高后降低,三点抗弯强度也随之变化。结论:固相含量与烧结温度对试件性能均有重要影响。55vol%ZTA浆料在1150℃半烧结后线性收缩率为(2.77±0.23)%,基本能达到近净尺寸成型,其强度(42±11)MPa也满足一定程度的机械加工要求。

Objective： To investigate the feasibility of forming dental zirconia--toughened alumina （ZTA） ceramic basal crowns by using gel--casting technique. The influences of solid content and half--sintering temperature on mechanical properties of ZTA basal crown were studied. Method： Micrometer Al2O3 and nanometer ZrO2 （quality ratio was 4：1） were used in this experiment. MgO and TiO2 were added as sintering accessory ingredient. Monomer and cross--linking agent were premixed in the deionized water. 50vol%, 53vol%, 55vol% and 57vol% slurry was formed with dispersant respectively. After gelasting, specimens were sintered at 1150℃, 1250℃, 1350℃, 1450℃. The mechanical properties were measured. And the section was observed under SEM. Results： With the same solid content, the three point strength, linear shrinkage and relative density was increased with sintering temperature. At the same sintering temperature, the linear shrinkage of specimens decreased with the increasing solid content. The relative density increased firstly and then decreased with the increasing solid content. Conclusion： Solid content and sintering temperature both have influences on the mechanical properties of ZTA ceramic. After sintered at 1150℃, the linear shrinkage of 55vol% specimens was （2.77 ± 0.23） %, which was near net shaping. The strength（42 ±11） MPa also meets the machinable requirement to a certain degree.