Parallel analysis of axial pressing, casting and PIM as routes for production of alnico8

Abstract

Samples of Alnico8 were prepared from the same starting powder by pressing, casting and powder injection moulding (PIM), respectively, and characterized by SEM and thermal analysis-DTA/TGA. Optimization of the sintering process was done for reaching the optimum of the energy product (BH)max for each type of samples. During sintering of the PIM specimens, special attention was paid to lowering the contents of residual C and O in the Alnico alloys since these interstitials affect the main magnetic properties. PIM samples were prepared using a feedstock composed of Alnico powder and a Catamold® (BASF) binder. For analysis of the thermal debinding of PIM samples, sintering was done in a dilatometer with coupled mass spectrometer. Shape anisotropy was induced by thermo magnetic treatment of all samples. Subsequently the main magnetic properties were measured and compared mutually and with the best literature results. It was clearly shown from the results obtained that PIM samples can attain the properties of Alnico samples made by classical routes. The microstructure of the sintered PIM samples was analyzed by SEM.