Preparation of barium hexa-aluminate ceramic fibres and refractories

AbstractBarium hexa-aluminate refractories, ceramic fibres, and ribbon can be obtained by sol–gel processing from precursor solutions containing a barium salt and an aluminium salt, the solutions having the stoichiometric BaO . 6Al2O3 composition. Barium chloride is a suitable barium salt and the preferred aluminium salts are the chlorohydrates Al2 (OH)n Cl6- n , with n being 1 or 2, preferably 1. The precursor solutions form filaments and ribbons, and also gels which can be used as binders in refractory grain mixes. The gel filaments and ribbons convert to barium hexa-aluminate ceramic fibres and ribbons on sintering, preferably by rapid heating to at least 1400°C. Previous work on the sintering of gels of stoichiometric BaO . 6Al2O3 composition is summarised and compared with the behaviour of oxide stoichiometric BaO . 6Al2O3 powder mixes of alumina and barium carbonate when sintered. The effect of chromium (III) addition is also summarised