Rheological study of alumina feedstock for a micro-powder injection moulding application

Abstract

Rheological analysis of an alumina feedstock is carried out to understand its flow behaviour. The alumina powder is mixed with indigenous binder system (combination of low-density polyethylene and paraffin wax) to prepare the feedstock. The prepared feedstock behaves like shear thinning material. Its temperature and time-dependent rheological character are analysed. Structural stability and spontaneous change of viscosity of the feedstock are checked during the shear jump. Effects of powder size and powder loading on the feedstock rheology are also tested. Injection of micro-channels is carried out with the prepared alumina feedstock followed by successful debinding and sintering. Around 97% of sintered density is achieved at 1540 °C sintering temperature with a soaking time of 30 min. The three-dimensional optical images confirm the shape retention of the micro-channel samples. These findings could be useful to choose the appropriate feedstock for different product development having micro-features.