Synthesis and characterization of CaO doped alumina-zirconia fibers by sol-gel process

Calcium oxide (CaO) doped Alumina-zirconia fibers were prepared by sol-gel process. The starting materials used for the preparation of alumina and zirconia sol were aluminium-tri-isopropoxide and zirconium oxychloride, respectively. Alumina sol and zirconia sol were mixed in definite proportions, so that the final composition contains 10wt% ZrO2. CaO was introduced into the mixed sol in the form of calcium nitrate such that the final composition contains 1 and 2wt%. Alumina-zirconia fibers were prepared from the mixed sol containing CaO, respectively. Sintered alumina-zirconia fiber has alpha-Al2O3, t-ZrO2, and m-ZrO2 phases. The phase transition to alpha-Al2O3 takes place at lower temperature in the presence of CaO. The addition of CaO increases the grain size.