牙科着色氧化钇稳定四方多晶氧化锆陶瓷的结构与性能

目的添加不同着色剂组合，配制着色的牙科氧化钇稳定四方多晶氧化锆（3Y-TZP）陶瓷，分析着色后材料的显微和晶相结构，并测定其理化、机械及抗低温时效性能。方法将TZ-3Y-S粉体与一定组分的着色剂球磨混合后，在200 MPa压力下等静压成型，先于1 050 ℃预烧结2 h，然后在1 500 ℃终烧结2 h，烧制5种具有一定颜色的氧化锆材料，测量烧结体的密度、收缩率、热膨胀系数、维氏硬度、三点弯曲强度、断裂韧性和化学稳定性；通过扫描电镜和X线衍射观察着色后材料的显微和晶相结构，并测试着色对材料抗低温时效性能的影响。结果着色后3Y-TZP陶瓷烧结密度在99.7%以上，烧结收缩率约20%，热膨胀系数为11×10-6·℃-1；晶粒大小均匀，主要断裂方式为穿晶断裂，主晶相为四方相氧化锆（t-ZrO2）；在弱酸性条件下具有较好的化学稳定性；5组着色氧化锆陶瓷的三点弯曲强度较未着色组略有降低，但均在900 MPa以上，断裂韧性略有提高，经低温时效处理后四方相到单斜相（m-ZrO2）的相变量约40%，但弯曲强度没有降低。结论3Y-TZP陶瓷经过着色后，具有优良的理化和机械性能，能够满足牙科临床应用的要求。

Structure and properties of colored dental tetragonai zirconia stabilized by yttrium ceramics

Objective To investigate the structure, mechanical and low temperature aging properties of colored dental zirconia ceramics. Methods 5 graded colored dental zirconia ceramics were made by adding colorants and their combinations into a 3Y-TZP（tetragonal zirconia stabilized by 3mol% yttrium） powder, the green body were compacted at 200 MPa, pre-sinter at 1 050 ℃ and maintained for 2 h, then densely sintered at 1 500 ℃ for 2 h. Specimens were cut from each of the 5 graded colored blocks. Physical, mechanical properties as well as chemical stability were tested, microstructure were observed, crystalline phase were identified by X-ray diffraction（XRD）, aging properties were assessed by measurement of the relative content of monoclinic phase and bending strength testing. Results The overall density of colored zirconia ceramics was over 99.7%, linear shrinkage was about 20%, while thermal expansion coefficient was about 11×10-6·℃-1, the crystalline phase was tetragonal, bending strength was over 900 MPa which was slightly lowered than that of the uncolored zirconia, fracture toughness was slightly higher. Good chemical stability in acetic acid was observed. After aging treatment, tetragonal-to-monoclinic phase transformation was detected up to 40%, while bending strength was not significantly degraded. Conclusion The results showed that colored 3Y-TZP ceramics presented good mechanical properties even after aging treatments, and was suitable for dental clinical use.