Synthesis and characterization of zirconia doped alumina nanopowder by citrate–nitrate process

Al2O3–ZrO2 nanopowders containing 5–20 wt.% ZrO2 was synthesized by a simple aqueous sol–gel method using a citrate polymeric precursor derived from aluminium nitrate, zirconium oxychloride and citric acid mixed solution. The thermal decomposition of the precursor and subsequent formation of α-Al2O3 was investigated by differential thermal analysis. X-ray diffraction analysis shows that the phases present at 1200 °C are α-Al2O3 and t-ZrO2 irrespective of zirconia content. The t-ZrO2 is found to increase with increase in zirconia content. FTIR also confirms the formation of α-Al2O3 incorroboration with X-ray studies. TEM micrograph of calcined powder revealed nanosize spherical particle of ∼75 nm. EDAX confirmed the presence of alumina and zirconia particle in the nanopowder calcined at 1200 °C.