Development and Characterization of Polymer Mixture (Binder) Based on Polyethylene Glycol (PEG) for a Superalloy A-286 to Powder Injection Moulding (MIM) Process

Abstract

Metal injection moulding (MIM) has over the past decade established itself as a competitive manufacturing process to produce in large quantities small precision components with complex shape which would be costly to produce by alternative methods. In this process, during the injection phase, segregation appears in the feedstock and defects will be appears in the component during the sintering. To limit this effect, during decades a vast variety of binder systems have been developed. Binder systems are formulated as a mixture of different organic or inorganic substances with several functions. Binder system has the main commitments of giving the necessary rheological behavior to the feedstocks for injection moulding to transport the powder particles into the mould cavity and the cohesion of the green part.In this paper a study of the behavior of binders based on polyethylene glycol (PEG) and feedstocks based on superalloy A-286 powder were investigated by Fourier Transform InfraRed spectroscopy (FTIR) coupling with rheology. This methodology permits to compare the rheological behavior of the materials with the thermal behavior of the binder at a temperature close to the temperature of injection. Analyzes was made for the mixing and injection process. It is shows relationship between interactions and miscibility of polymer and influences on the rheological and mechanical behavior. All methodologies revealed no chemical interactions between the powder and the binder. This result shows the formulation of binder for the superalloy A-286 is not homogenous and the PEG is degraded under mixing and injection process conditions of this kind of formulation of feedstock.