Dolomite stabilized zirconia for refractory application : Part-I phase analysis, densification behavior and microstructure of partial stabilized zirconia
Keywords:
Dolomite stabilization, Calcination, Partial Stabilized Zirconia, MicrostructureAbstract
In the continuous casting of steel, Zircon and Zirconia based products are used due to its high thermal stability, excellent erosion resistance, self-opening, consistent casting speed and resistance to oxygen lancing during casting for removal of inclusion clogging and to streamline the flow. Higher casting sequences of molten steel CaO or MgO stabilized zirconia nozzles were being used and for industrial application point of view, dolomite stabilized zirconia (DSZ) could be a better substitute for the stabilization of zirconia. DSZ samples were prepared having 3,4,5,6 and 7 mole % of dolomite by solid state route using high purity monoclinic zirconia and dolomite. The decomposition behaviour, phase stability and densification behavior of co-grounded zirconia-dolomite mixer were studied. It was observed that finer dolomite particle size (-63?m) resulted in higher amount of t/c ZrO2 phase stabilization as a function of temperature. The effect of pre-calcination temperature on phase formation and densification was optimized. Higher t-phases were achieved with 3, 4 and 5 mol% dolomite whereas 6 and 7 mol% dolomite had more of cubic phases. The non-isothermal densification of the pre calcination compact showed two stage sintering behavior. Effect of sintering schedule on densification and phase formation of DSZ was co-related. Substructure grain was observed in cubic grain for 5mole% dolomite addition in SEM micrograph. Tetragonal zirconia precipitates in cubic zirconia with increasing dolomite content in the partial stabilized zirconia.
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References
Stevens, R. (1986). An Introduction to Zirconia. Magnesium Elektron Ltd., Twickenham : UK.
Subbarao, E. C., Maiti, H. S. and Srivastava, K. K. (1974). Martensitic transformation in zirconia. Phys. Status Solidi A. 21 : 9-40.
Durrani, S.K., Akhtar, J., Ahmad, M. and Hussain, M.A. (2006). Synthesis and characterization of low density calcia stabilized zirconia ceramic for high temperature furnace application. Mater. Chem. Phys. 100 : 324-328.
Jensen, D.G. (1996). Enhanced Toughness of a Partially Stabilised Zirconia at Elevated Temperatures. J. Eur. Ceram. Soc. 16(8) : 825-831.
Rackers, K.G. and Thomas, B.G. (1995). Clogging in continuous casting tundish nozzles. In 78th Steelmaking Conference. Nashville, TN, April 2. ISS, Warrendale, PA. 78 : 723-734.
Moulden, G.T. and Sabol, R. (2000). Development of doloma tundish nozzles to reduce alumina clogging. Ironmaking Steelmaking. 27(6) : 35-38.
Sahu, J. K., Chaudhuri, S. K. and Prasad, B. (1997). Development of alumina clogging resistance nozzles for continuous casting of steel. Proceedings of the Unified International Technical Conference on Refractories. 1435-1440.
Otsuka, R. (1986). Recent studies on the decomposition of the dolomite group by thermal analysis. Thermochim. Acta. 100(1) : 69-80.
Engler, P., Santana, M.W., Mittleman, M.L. and Balazs, D. (1988). Non-isothermal in situ XRD analysis of dolomite decomposition. Rigaku J. 5(2) : 3-8.
Bhattacharyya, S., Pratihar, S.K., Sinha, R.K., Behera, R.C. and Ganguly, R.I. (2002). Preparation of alumina–high zirconia microcomposite by combined gelprecipitation. Mater. Lett. 53(6) : 425-431.
Coble, R.L. (1961). Sintering crystalline solids. I. intermediate and final state diffusion. J. Appl. Phys. 32(5) : 787-792.
Kingery, W.D. and Berg, M. (1955). Study of Initial Stages of Sintering Solids by Viscous Flow, Evaporation-Condensation, and Self-Diffusion. J. Appl. Phys. 26(10) : 1205–12.
Rudyak, I. N. and Karaulov, A. G. (1972). Sintering of zirconia as a function of the stabilizer concentration. Ogneupory. 10 : 41-44.
Mustafa, E., Wilhelm, M. and Wruss, W. (2002). Microstructure and phase stability of YPSZ co-doped with MgO or CaO prepared via polymeric route. Br. Ceram. Trans. 101(2) : 78-83.
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