INFILTRATION OF POROUS ZIRCON PREFORMS WITH ALUMINA PRECURSOR

A process is described which involves infiltration of aluminum nitrate into partially sintered (porous) zircon bodies. Infiltration kinetics were studied using infiltration curves with two distinct regions. The final infiltrated samples were sintered at 1600 °C for 2 h and yielded specimens containing the tetragonal zirconia. The experimental results show that in spite of the similar porosity of the infiltrated preform and of pure zircon sintered at 1600 °C, the former has a higher flexural strength and fracture toughness due to the incorporation of the Zr02 particles and the elongated mullite grains resulting from the infiltration and subsequent heating ofthe preform