Densification and grain-growth behavior of various amounts of SiO2 doped 8YSCZ/SiO2 composites

The effect of SiO2 addition on densification and grain-growth behavior of 8YSCZ/SiO2 composites was investigated using high purity 8 mol% yttria-stabilized cubic zirconia powders (8YSCZ) doped with 0, 1, 5, 10 wt% SiO2. The specimens were sintered at 1400 degrees C for 1 hour. It was seen that the sintered density increased with SiO2 content up to 1 wt% and further. increase in SiO2 content led to a decrease in density. The enhanced density with increasing SiO2 content up to 1 wt% could be mainly attributable to liquid phase sintering. For grain growth measurements, the specimens sintered at 1400 degrees C were annealed at 1400, 1500, and 1600 degrees C for 10, 50, and 100 hours. The experimental results showed that the grain growth in 8YSCZ/SiO2 composites occurred more slowly than that in undoped 8YSCZ. Also, the grain growth rate decreased with increasing SiO2 content, The grain growth exponent value and the activation energy for undoped 8YSCZ were found to be 2 and 289kJ/Mol, respectively. The addition of SiO2 raised the grain growth exponent value to 3, and activation energy for the grain growth process was increased from 289 to 420 kJ/mol for the addition of SiO2 from 0 to 10 wt%.