The effect of simultaneous addition of Si and Co on microstructure and magnetic properties of nanostructured iron prepared by mechanical alloying

The aim of present work is to study the effect of Si contents on structural and magnetic properties of nanostructured (Fe65Co35)100−xSix (x = 0, 10 and 20) powders prepared by mechanical alloying. The structural and magnetic properties of the mechanically alloyed powders were investigated by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and a Vibration Sample Magnetometer (VSM). The resulting powders mainly consist of micron-sized particles with an average crystallite size of 18 nm. Morphological observations indicate that the addition of Si to the alloys leads to finer particles. According to the XRD test results, by increasing the milling time and/or the Si content, the grain size decreases and the internal microstrain increases. The magnetic measurements indicate that the higher amount of Si leads to lower values of saturation magnetization. Besides, the results show that during initial stages of milling (up to 20 h), the coercivity increases and then decreases by further milling. Increasing the Si content, increases the reduction rate of coercivity.

► The Fe65–Co35 alloys are well known in having very high saturation magnetization.
► The addition of Si to the alloys leads to the finer particle sizes.
► Presence of Si will speed up the reduction rate of grain size to a critical value.
► Increasing the Si content, increases the reduction rate of coercivity.