Novel synthesis of advanced composites of α -Al 2 O 3 reinforced with Ce TZP through co-precipitation process

Abstract

The presence of zirconia grains in alumina matrix as a discrete second phase plays an important role in the development of high performance ceramics subjected to intensive thermal as well as mechanical stress. The recent development on transformation toughening by addition of CeO₂, Y₂O₃, MgO or CaO to zirconia in alumina matrixes offers a new generation ceramics with improved mechanical properties. The stabilisation of tetragonal or metastable tetragonal phases much depends on the type of additives, mole concentration and the processing route adopted. The present paper describes the synthesis of ultra fine powders of CeO₂ based tetragonal or metastable tetragonal zirconia polycrystals for developing suitable toughening characteristics of advanced ceramic composites of α-Al₂O₃ matrixes with particular concentration of Ce TZP by wet chemical simultaneous precipitation process. The degree of stabilisation of different percentages by mole varying from 6 to 12 mol.-%CeO₂ based zirconia polycrystal ceramics and advanced composites of α-Al₂O₃ matrixes with 10 wt-% Ce stabilised tetragonal zirconia polycrystals (Ce TZP) was studied through thermal and X-ray diffraction (XRD) analysis. The powder morphology, sintering behaviour, microstructure characteristic and mechanical properties such as hardness and fracture toughness of composites were also evaluated.