Synthesis and characterisation of amorphous Fe38.5Co38.5Nb7B15Cu1 powders via mechanosynthesis using industrial raw materials

Abstract

This work presents a comparative study on the HITPERM type alloy prepared by wet and dry mechanical alloying. The chosen composition for this study was Fe38.5Co38.5Nb7B15Cu1. The powders were obtained via mechanical alloying starting from elemental Fe, Co, Cu powders and the ferroalloys of Nb and B. Mechanical alloying experiments were done using a high energy planetary ball mill Pulverizette 6 under Ar atmosphere. It was observed that for the powder milled in wet milling conditions, using benzene as process control agent, the alloy amorphisation occurs after 40 h of milling. X-ray diffraction patterns highlighted the alloy amorphisation. In the dry milled powder case, the amorphisation did not occur even after 100 h of milling. The thermal stability and the crystallisation kinetics of the amorphous powders were investigated via differential scanning calorimetry and in-situ high-temperature X-ray diffraction. The powders morphology and chemical homogeneity were studied by scanning electron microscopy and X-ray microanalysis. The saturation magnetisation also reveals a difference between wet and dry milled powders versus milling time. The obtained results concerning the alloy amorphisation and its thermal stability are compared with available data of the literature.