LAUSR

Abstract In this work, cement-free alumina castables with different fiber additives were produced. The effect of commercial polypropylene fibers was compared to that of magnesium borate precursor fibers produced by electrospinning. The drying behavior of different batches was monitored by means of thermogravimetry. Elastic moduli were estimated in dried, sintered and thermally-shocked samples through the impulse excitation technique. The mechanical strength as cold modulus of rupture (CMOR) was measured by three-point bending tests. The open porosity and bulk density after sintering were assessed by water immersion. The thermal shock resistance was evaluated by heating the samples up to 950 ∘C and then quenching with compressed air. After 1 or 5 thermal shock cycles, the residual CMOR was determined. The microstructure of fracture surfaces was analyzed by scanning electron microscopy (SEM). The possible formation of new phases during thermal treatment was also assessed by means of XRD. Finally, the refractoriness under load was measured.