EFFECT OF SUPPORTED NA+ IONS ON THE TEXTURE PROPERTIES OF ZRO2

The dispersion of sodium nitrate on tetragonal zirconia and the effect of the dispersed sodium species on the textural properties of the sup port are investigated by using XRD, LRS, DTA, and BET surface area mea surement. The results indicate that NaNO3 can be dispersed on the surf ace of tetragonal zirconia by the incorporation of Nai ions into the s urface vacant sites. The experimentally measured dispersion capacity o f sodium nitrate an t-ZrO2 is consistent with the value deduced from t he incorporation model, i.e., 8.6 Na+/nm(2)t-ZrO2. The dispersed Na+ i on species can effectively hinder the sintering of zirconia and preven t its phase transformation from tetragonal to monoclinic. The crystall ization temperature and surface area of the samples are strongly depen dent on the loaded amount of NaNO3 when it is below the dispersion cap acity. Crystalline NaNO3 is detected when its loading exceeds the disp ersion capacity and has less effect an the structural and textural pro perties of the t-ZrO2. (C) 1998 Academic Press.