Synthesis and structural characterization of Ni-B nanoalloys

Mut, Lütfiye Seda
Within the scope of this study, it is aimed to produce and to realize the structural characterization of Nickel Boron nanocrystalline/amorphous, alloy/intermetallic phase powders. Mechanical alloying by high energy ball milling was determined as production method. X-ray diffraction (XRD) for phase analysis, Scanning Electron Microscopy (SEM) for microstructure and morphological analysis, Vibrating Sample Magnetometer (VSM) for change in magnetic properties and Differential Scanning Calorimetry (DSC) for thermal analysis were determined as methods for characterization of produced powders. Milling operation has been carried out with two different compositions as Ni80B20 and Ni60B40, prepared from elemental Nickel and Boron powders. For both compositions, after 1, 5, 10, 20, 40, 60 and 80 hours of milling, samples have been taken out and analyses have been carried out. According to the structural analyses, there are no remarkable additional peaks belonging to any intermetallic compounds until 40 hours of milling. For Ni80B20 composition, Ni3B and Ni2B peaks after 40 hours of milling and for Ni60B40, Ni3B peak after 60 hours of milling were observed notably and with the increase in milling time intensities of these peaks increased. Besides, XRD and SEM analyses have shown that particle size and/or crystallite size decreased with increasing milling time. Additionally, along with peak broadening in XRD curves, DSC analyses have pointed out the formation of amorphous structure. As for, changes in magnetic properties it was shown that with increase in milling time, saturation magnetization shows a general decrease and hysteresis increases.