Preparation of tetragonal zirconia powders by a solid state reaction: Kinetics, phases and morphology
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Powders of tetragonal (t)ZrO2 have been prepared by a solid state reaction between sodium metazirconate and sodium metaphosphate. The reaction temperatures and times have been varied between 450 and 550°C and 5 and 75 h, respectively. Zirconia powder, mostly in thet andt′ phases, is obtained. The yield of ZrO2 powder increases monotonically with time at all reaction temperatures according to a phase boundary controlled kinetics. The fraction oft phase also increases with time at 450°C and 500°C but goes through a maximum at 550°C, the highest temperature employed. A maximum of 55% of the precursor monoclinic zirconia (used to prepare sodium meta zirconate) is converted tot phase at 500°C/75 h. The ZrO2 powder consists of crystallites of size 9–25 nm agglomerated into particles having average size between 2 and 4µm. The agglomerates have a breaking strength of 100 MPa. A hydrothermal treatment is found to break the agglomerates into smaller sizes. Grinding the powder in a mortar and pestle converts only 12% of thet phase into monoclinic, indicating that substantial fraction of the tetragonal phase is the non transformable varietyt′. Heating experiments also confirm this.
KeywordsTetragonal zirconia powder preparation solid state reaction
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- Brook R J 1980 inAdvances in ceramics (eds) A H Heuer and L W Hobbs (Columbus, Ohio: The American Ceramic Society) Vol. 3, p. 272Google Scholar
- Graff M A C G Van de, Keizer K and Burggraaf A J 1980 inScience of ceramics (ed.) H Hausner (Berlin: Deutche Keramiche Gesellschabt) Vol. 10, p. 983Google Scholar
- Graff M A C G Van de and Burggraaf A J 1983 inAdvances in ceramics (eds) N Claussen, M Ruhle and A H Heuer (Columbus, Ohio: The American Ceramic Society) Vol. 12, p. 744Google Scholar
- Haberko K and Pyda W 1983 inAdvances in ceramics (eds) N Claussen, M Ruhle and A H Heuer (Columbus, Ohio: The American Ceramic Society) Vol. 12, p. 774Google Scholar
- Heistand II R H, Ogure Y, Okamura H, Moffalt W C, Novich R, Barringer E A and Bowen H K 1985 inScience of ceramic processing (eds) C L Hench and R Ulrich Donald (New York: John Wiley and Sons) pp. 482–497Google Scholar
- Jean V S 1991Br. Ceram. Proc. 47 45Google Scholar
- Maher G H, Hutchins C E and Ross S D 1993Am. Ceram. Soc. Bull. 72 72Google Scholar
- Roosen A and Hauser H 1983 inAdvances in ceramics (eds) N Claussen, M Ruhle and A H Heuer (Columbus, Ohio: The American Ceramic Society) Vol. 12, p. 714Google Scholar
- Sirkar A and Brett N H 1970Trans. Br. Ceram. Soc. 69 131Google Scholar
- Toraya H, Yoshimara M and Somiya S 1984J. Am. Ceram. Soc. 67 C-119Google Scholar