Effect of binder's size and chemistry on pure aluminium-oxide vacuum formed ceramic fibre boards

Pure aluminium oxide vacuum-formed fibreboards were obtained from new generation of alumina fibres synthesized by the sol-gel method. The effect of the chemical composition and the particle size of the binder on the vacuum-formed boards was examined. High-temperature testing took place at 1500 °C for 24 h. The mechanical properties (both modulus and compressive strength) are better with Boehmite than with aluminium hydroxide. Decreasing the size of the binder particles enhances these mechanical properties. Field emission scanning electron microscopy was used to study the micro-scale morphology. Well-developed crystals can be found in both the fibres and binders, regardless of the binder system used, after the prolonged high-temperature treatment. The smaller binder particles cause decreased crystal size. The most stable α-aluminium oxide phase was identified by XRD in all systems.