Study of magnetoelastic properties of pure nickel parts produced by metal injection moulding

The production of smart materials such as those with magnetoelastic properties is of increasing interest for some application as position transducers. The use of the metal injection moulding process permits the production of small parts with complex geometries as well as avoiding common defects produced by other processing techniques. In this study, a feedstock based on pure nickel and thermoplastic binder has been designed and moulded to have specific cylindrical geometry and defect-free green specimens. The parts were sintered changing several processing parameters that have influence on magnetoelastic effects. These effects were studied in terms of the field-dependent elastic modulus, which was estimated by subjecting the specimens to free longitudinal vibration while they remained within different magnetic fields from 0 to 2000 Oe. The optimal sintering parameters turned out to be 1325 °C for the temperature and 12 h for the holding time, whereas the estimated field-dependent elastic modulus variation (8%) was higher in comparison to variations in parts obtained by conventional processing (4%). Keywords: Metal injection moulding, Magnetomechanical properties, Smart materials, Sintering