Effect of Sintering Temperature on Microstructure and Properties of Zirconia Ceramics for the Needs of Nuclear Energy

Abstract

The paper provides experimental results of obtaining high-density ZrO2+3%Y2O3 ceramics, which is promising for use as a matrix for immobilization of HLW. The effect of sintering temperature in the range of 1100...1650 °C on the microstructure of the sintered tablets was studied. Phase composition and microstructure of experimental samples were characterized by XRD and SEM. Grain size distribution analysis was carried out using the "Thixomet" image analyzer. Microhardness was determined using a metallographic complex LECO (USA), an inverted microscope IM-3MET and a hardness tester UIT HVB-30. It was established that increase in the sintering temperature leads to a significant increase in the average grain size (from 85 nm to 1000 nm) and increase in the density of the sintered tablets. Sintering temperature should be at least 1550...1650 ºС to produce high-dense ceramics (97...98 % of theoretical value). Obtained ceramics is characterized by high values of microhardness HV > 12 GPa and crack resistance of 5.5...6.3 MPa·m1/2.

Keywords

• Zirconium oxide
• Sintering
• Microstructure
• Microhardness
• Crack resistance