Fabrication and characterization of zirconia-toughened alumina obtained by inorganic and organic precursors

Article abstract of DOI:10.1007/BF02385615

The authors prepared ZTA using different precursors and compared their microstructures. The coprecipitation of aluminium and zirconium chlorides gives an hydroxide mixture. Thus the zirconium hydrate is amorphous, and the aluminium hydroxide structure varies with the precipitation temperature and pH values at the end of the neutralization. Alumina was mixed with zirconia obtained by gas-phase reaction. Zirconia was prepared by vaporization of zirconium chloride in an oxygen-hydrogen flame. Alumina powder was impregnated by a zirconium acetate solution. Zirconium acetate was thermally decomposed in a spray-dryer, then by calcination. The cohydrolysis of II Al-butoxide and IV Zr-propoxide was carried out in an alkaline solution. The hydrolysis pH (10 or 12) changes the grain size of the oxide powders. Mechanical property measurements and microstructural analysis allow a comparison of the different composites. The mean grain-size evolution differs according to the preparative route, and may be varied by different elaboration parameters. Fine microstructures were always observed. The mean grain size of dispersed zirconia being very small there was little influence of transformation toughening. There was a large increase in rupture strength, while toughness was not noticeably improved.