PREPARATION OF FE-NI BASED METAL-METALLOID AMORPHOUS POWDERS BY MECHANICAL ALLOYING

Fe40Ni40B6P14 and Fe40Ni40Si6P14 alloys, in both a nanostructural and a disordered amorphous-like state, were produced from different precur sors using the ball milling technique. The development of such metasta ble phases was investigated by X-ray diffraction, differential scannin g calorimetry and scanning electron microscopy. After the first 20 h, the diffraction peaks of the precursors disappeared, and the deformati on during milling reduced the crystallite size of the alloys to 3-6 nm . The final crystallite size of the powders depended on the compositio n of the material as well as on the precursors utilized. The different ial scanning calorimetry results revealed several exothermic peaks, in dicating the crystallization of the amorphous-like state. The crystall ization enthalpy was evaluated and the values obtained presented a max imum after 35 h of milling. The results were compared with data for ra pidly quenched materials. The effect of the milling conditions on phas e formation was analyzed.