Effect of PEG molecular weight on rheological properties of Ti-MIM feedstocks and water debinding behaviour

Abstract

Polyethylene glycol (PEG) based binder systems are garnering increasing attention because of the environmentally friendly nature of the water-soluble PEG. Rheological properties of the feedstock are essential to metal injection moulding (MIM). Intriguingly the effect of PEG molecular weight on rheological properties of the feedstock and its water debinding behaviour has not been well investigated. In this work, four molecular weights of PEG, i.e. 1500, 4000, 10,000 and 20,000g/mol were selected and PEG/polymethyl methacrylate (PMMA) based feedstocks were formulated with titanium metal powder. We reported a systematic investigation of the rheological properties of the prepared feedstocks with capillary rheometry and the study of the effects of shear rate and temperature on viscosity. The water debinding behaviour of each feedstock was also investigated in terms of debinding temperature and PEG molecular weight.