EFFECT OF GRAIN-BOUNDARY SEGREGATION ON LOW-TEMPERATURE DEGRADATION OF ORAL 3Y-TZP CERAMICS CO-DOPED WITH GEO2 AND TIO2.

Purpose: To explore the improvement of its low temperature aging resistance by co-doping oral 3Y-TZP with TiO₂ and GeO₂. Methods: After the samples of 3Y-TZP co-doped with GeO₂ and TiO₂ were prepared by mechanical ball milling, drying, and pressureless sintering, the microstructure was studied by scanning transmission electron microscope, energy spectrometer, and high angle annular dark field detector. After treatment in the autoclave, the conversion of all samples was measured by XRD. Results: After mechanical ball milling for 24 hours, the particle size of the composite powder of 3Y-TZP co-doped with GeO₂ and TiO₂ is uniform, distributed at about 50 nm, the particle shape is basically spherical, the dispersion is good, but there is a small amount of agglomeration; Tetravalent stabilizers (Ge 4 + , Ti 4 + ) can inhibit the low-temperature aging effect of zirconia materials. With the increase of germanium oxide doping, the hydrothermal degradation resistance of zirconia can be improved. GeO₂ doped 3Y-TZP has better low temperature aging resistance than TiO₂ doped 3Y-TZP. With the increase of dopant content, the degree of grain boundary segregation increases, but even if the doping amount of Ge 4 + is small, the degree of grain boundary segregation can be comparable to that of Ti 4 + with a large doping amount. Conclusion: In this paper, the composite powder of 3Y-TZP co-doped with GeO₂ and TiO₂ with uniform particle size and good dispersion was prepared by mechanical ball milling. The preparation process is simple, the energy consumption is low, and the cumbersome processes of the co-precipitation method and liquid-phase method are avoided. On the other hand, adding GeO₂ and TiO₂ can enhance the low-temperature aging resistance of 3Y-TZP ceramics. GeO₂ is superior to TiO₂ in low-temperature degradation resistance, which can be used as the first choice. This study contributes to the research on doping cations of dental zirconia and provides a reference for dentists to choose a reasonable zirconia material. [ABSTRACT FROM AUTHOR]