Advanced 3Y-TZP bioceramic doped with Al2O3 and MnO2 particles potentially for biomedical applications: study on mechanical and degradation properties

Abstract

The effectiveness of Al2O3 and MnO2 in enhancing mechanical properties and retarding degradation of 3 mol% yttria stabilized tetragonal zirconia polycrystalline (3Y-TZP) ceramic samples was evaluated by pressureless sintering at temperatures ranging from 1250 °C to 1550 °C with standard holding time of 2 h. It was observed that the inclusion of Al2O3 and MnO2 into 3Y-TZP was beneficial for the improvement of mechanical properties and ageing resistance. The optimum amounts of dopants were determined to be of 0.6 wt% Al2O3 and 0.4 wt% MnO2. Microstructural investigation revealed that at the same temperature, the tetragonal grain size was not influenced by the increase of dopant levels. With optimum dopants the 3Y-TZP ceramic (density 6.1 g/cm3) samples demonstrated the Vickers hardness of 11.6 GPa, fracture toughness, KIC of 9.8 MPa m1/2, flexural strength of 900 MPa and Young's modulus of 210 GPa. Furthermore, the efficacy of the dopants (MnO2 and Al2O3) in retarding low-temperature degradation of 3Y-TZP ceramic during exposure in Ringer's solution at 37 °C was also evaluated. Overall, the degradation rate and weight loss of 0.6 wt% Al2O3 and 0.4 wt% MnO2 ceramic samples were 0.66% in 8 weeks as compared to the undoped samples. The 3Y-TZP bioceramic doped with Al2O3 and MnO2 could be a potential candidate material for biomedical applications (e.g. hip implants) due to its improved mechanical properties and superior ageing resistance. Keywords: Bioceramic, 3Y-TZP, Mechanical properties, Degradation, Ringer's solution, Hip implant