Influence of spinning parameters on synthesis of alumina fibres by centrifugal spinning

The present study investigates the synthesis of alumina fibres of 5-15 µm dia. by sol-gel process through centrifugal spinning. Among various spinning parameters such as rpm, viscosity, humidity, chamber temperature etc., effect of rpm and viscosity on quality of spun fibres was examined in order to spin less defective (less shots) fibres. From the rpm vs viscosity experiments, it was concluded that viscosity between 13 and 42 Pa.s with 3000 rpm was favourable for obtaining fibres containing less shots. It was shown that besides viscosity, refractive index and percent weight loss of the aged sol can be used as indicator for determining spinnability of alumina precursor sols. Influence of only preheating and continuous heating of the chamber during spinning were also investigated and it was found that only preheating did not help in producing fibres. Besides this, influence of hot air blower (HAB) aligned in different directions with respect to the spinnerette, on fibre quality was tested. It was observed that the quality of fibres did not change due to change in HAB direction.