Microstructural Development in Calcium Hexaluminate with and without Fe2O3 Doping at Different Forming Method
1 Refractory Division, CSIR-Central Glass & Ceramic Research Institute, Kolkata 700 032, India
2 Refractory Division, CSIR-Central Glass & Ceramic Research Institute, Kolkata 700 032/India
Revision
Volume 6, Issue 4, Pages 61 - 65
Abstract
Calcium hexaluminate (CA6) was synthesized from a mixture of anhydrous Ca(OH)2 and Al(OH)3 with or without Fe2O3 doping at a predetermined temperature of 1550 °C. Two different forming methods (uniaxial and isostatic pressing) were adopted to fabricate samples. Uniaxially pressed sample without Fe2O3 results higher porosity (17,14 %) with the formation of hexagonal platelet CA6 grains while isostatic pressed sample with lower porosity (8,22 %) resulted more equiaxed CA6 grains. Low concentration of Fe2O3 (5 %) did not formed CAF2, which is the only stable phase in CaO–Al2O3–Fe2O3 system. However it was observed that 5 % Fe2O3 addition enhances the grain growth which is beneficial for refractory application.
Keywords
calcium hexaluminate, forming methods, additives, microstructure
References
[1] Caballero, A.; et al.: Constitution of calcined refractory-grade bauxites: An interpretation. Ceramic Int. 11 (1985) [2] 45–50 [2] Abou-Sekkina, M.M.; et al.: Phase composition of bauxite-based refractory castables. Ceramic Int. 37 (2011) 411–418 [3] Das, S.K.: Some studies on the hydraulic activity and other related properties of calcium aluminates. Ph. D. Thesis, University of Calcutta, India (1994) [4] Nurse, R.W.; Welch, J.H.; Majumdar, A.J.: The CaO-Al2O3 system in a moisture-free atmosphere. Trans. Br. Ceram. Soc. 64 (1965) 409–418 [5] Büchel, G.; Buhr, A.; Gierisch, D.; (all Almatis GmbH, Frankfurt/Ludwigshafen, Germany) Racher, R.P. (Almatis Inc., Leetsdale, USA): Bonite – A new raw material alternative for refractory innovations [6] Kohatsu, I.; Brundley, G.W.: Solid state reactions between CaO and Al2O3. Physics and Chemistry (Neue Folge) 60 (1968) 79–89 [7] Callender, R.L.; Barren, A.R.: New route to hexaluminate ceramics via a novel transmetalation reaction. Ceramic Engin. and Sci. Proc. 20 (1999) 27–34 [8] Collongues, R.; Gourier, D.; Harari, A.K.: Magnetoplumbite related oxides. Ann. Rev. Mater. Sci. 20 (1990) 51–82 [9] Park, J.G.; Cormack, A.N. : Potential models for multicomponent oxides-hexaaluminates. Philos. Mag. B 73 (1996) 21–31 [10] Collongues, R.; et al: Crystal growth and characterization of new laser materials. J. of Crystal Growth 128 (1993) 986–990 [11] Ravichandran, D.; et al.: Crystal chemistry and luminescence of the Eu2+-activated alkaline earth aluminate phosphors. Displays 19 (1999) 197–203 [12] Morgan, R.E.D.; Cirlin, E.H.: The magnetoplumbite crystal structure as a radwaste host. J. Amer. Ceram. Soc. 65 (1982) 114–115 [13] Machida, M.; et. al.: High temperature steam reforming of hydrocarbons over nickel/hexaluminate catalysts. Chem. Lett. 2 (1991) 231–234 [14] Asmi, D.; Low, I.M.: Self-reinforced Ca-hexaluminate/alumina composites with graded microstructures. Ceramics Int. 34 (2008) 311–316 [15] Dominguez, C.; et al.: Microstructure development in calcium hexaluminate. J. Europ. Ceram. Soc. 21 (2001) 381–387 [16] Costa, G.; et al.: Ni-doped hibonite (CaAl12O19): A new turquoise blue ceramic pigment. J. Europ. Ceram. Soc. 29 (2009) 2671–2678 [17] Dominguez, C.; Torrecillas, R.: Influence of Fe3+ on sintering and microstructural evolution of reaction sintered calcium hexaluminate. J. Europ. Ceram. Soc. 18 (1998) 1373–1379 [18] Dayal, R.R.; Glasser, F.P.: Phase relations in the system CaO-Al2O3-Fe2O3. In: Science of Ceramics. Ed. G.H. Stewart. London 1967, 191–214 [19] Lister, D.H.; Glasser, F.P.: Phase relations in the system CaO–Al2O3-iron oxide. Trans. Brit. Ceram. Soc. 66 (1967) [7] 293–305 [20] Tak, J.B.; Young, D.J.: Sulfur corrosion of calcium aluminate bonded castables. Ceram. Bull. 61 (1982) [7] 725–727 [21] Kulkarni, D.K.; Prakash; C.S.: Structural and magnetic properties of CaAl4Fe8O19. Bull. Mater. Sci. 17 (1994) [1] 35–39 [22]. Prakash, C.S.; et al.: Substitutional effect of magnetic behavior in calcium hexaferrite. J. Magnetism Magnetic Mater. 140–144 (1995) 2089–2090
Copyright
Göller Verlag GmbH
