Effect of organic additives on the properties of sol-gel spun alumina-zirconia fibre

Alumina-zirconia fibres (Al2O3-10 wt.% ZrO2) were prepared by the sol-gel method with organic additives viz. hydroxy ethyl cellulose (HEC) and polyvinyl alcohol (PVA). As the organic content is increased, the phase transition to alpha-Al2O3 is retarded in the presence of hydroxy ethyl cellulose and enhanced in the presence of polyvinyl alcohol. The phases present in the sintered fibres are alpha-Al2O3, t-ZrO2 and m-ZrO2. Infra red spectra of the sintered fibres show bands corresponding to alpha-Al2O3. The surface morphology of fibres prepared with higher amount of organics shows equiaxed grains with relatively dense microstructure for fibre prepared with hydroxy ethyl cellulose, whereas the structure is porous with polyvinyl alcohol. Tensile strength decreases with the increase in organic content.