Microstructure and properties of nanocrystalline lab6 powders synthesized in a high energy planetary ball mill

In this study, a room temperature mechano-chemical route was investigated for the synthesis of LaB6 powders from La2O3, B2O3 and Mg containing blends. The reaction was driven by high energy ball milling of powder blends in a planetary ball mill rotating with a speed of 400 rpm. The reaction products were gradually examined in terms of milling duration. Subsequent to the mechano-chemical synthesis, unwanted MgO phase was removed from the boride phase by HCl acid leaching under the effect of ultrasonic stirring and heating. Pure LaB6 powders were obtained after repeated centrifuging, repeated decanting, repeated washing and drying. Phase and microstructural characterizations of the milled and leached powders were performed using X-ray diffractometry (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) techniques. The amounts of elements (Mg and B) in the supernatant liquid were analyzed in an atomic absorption spectrometer (AAS). Magnetic properties of the pure LaB6 powders were determined by a vibrating sample magnetometer (VSM). Following the cold pressing of the pure powders, electrical resistance of LaB6 compacts was measured by using four-point probe method.