SOL-GEL ZIRCONIA COATINGS AIMED AT DUST SUPPRESSION IN ALUMINOSILICATE HIGH-TEMPERATURE INSULATING BLANKETS

The feasibility of reducing the amount of loftable fibres in aluminosi licate blankets by coating with sol-gel zirconia was studied. A zircon ium alkoxide based solution was employed to coat small samples of blan ket using a dip-coating technique. The zirconia coatings and two grade s of blanket were analysed using DTA, XRD, SEM and optical microscopy techniques to characterize any reactions and phase changes occurring i n the system over a range of temperatures. It was found that dip-coate d samples fired at temperatures of 700-800 degrees C displayed reasona bly coherent coatings providing an ''anchoring'' effect at the surface of the material by bonding loose surface fibres in a network of zirco nia.