H. Tomaszewski et K. Godwod, INFLUENCE OF OXYGEN PARTIAL-PRESSURE ON THE METASTABILITY OF UNDOPED ZIRCONIA DISPERSED IN ALUMINA MATRIX, Journal of the European Ceramic Society, 15(1), 1995, pp. 17-23
The influence of oxygen content in the sintering atmosphere on, zircon
ia phases in alumina-zirconia ceramics was studied. As was demonstrate
d, in the case of samples sintered in art atmosphere with oxygen parti
al pressure between 2.80 +/- 10(-5) Pa and 2.80 X 10(-2) Pa, 100% of z
irconia was found to be in the cubic form. The appearance of transform
able cubic zirconia is a result of oxygen vacancy concentration in zir
conia. The increase of oxygen pal tial pressure and decrease of oxygen
vacancy concentration leads to a breakdown of the cubic phase which t
ransforms to the t- and/or m-phases. Critical values of oxygen vacancy
concentration responsible for the metastability of cubic and tetragon
al zirconia were estimated.