Compatibility improvement of Ti-MIM feedstock using liquid surfactant

To study the effect of different surfactants on the metal-and-binder interaction that has not been reported before, polyethylene glycol (PEG) and polymethyl methacrylate (PMMA) were used as the major and backbone constituents in the binder system. Three different surfactants - stearic acid (SA), peanut oil and castor oil - were chosen to prepare feedstocks of 60 vol% solid loading. Rheological properties analysis, fracture surface, and flexural strength studies were carried out to identify the suitable surfactant that yields feedstock with excellent mouldability. It is found that castor oil as surfactant results in excellent overall properties of feedstock by enhancing metal-and-binder interaction. The reason of this higher interaction lies in the chemistry of castor oil, which has more polar ester functional groups, which latch on the metal powder surface via dipole-dipole attractive forces. Therefore a better powder dispersion and higher powder-binder interaction is achieved.