Powder Technology, Vol.226, 246-252, 2012
Preparation and characterization of electroless Ni-Fe-P alloy films on fly ash cenospheres
The process of depositing Ni-Fe-P alloy films on fly ash cenospheres (FACs) through modified electroless plating is documented. A coupling procedure was used with gamma-aminopropyltriethoxy silane (APS) as coupling agent and silver nitrate as activator. The resultant Ni-Fe-P/FACs composites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC). X-ray diffractometry (XRD) and vibrating sample magnetometry (VSM). The results show that continuous and uniform films of Ni-Fe-P alloy were obtained on the surfaces of the FACs. DSC traces indicated that two distinct exothermic peaks appeared during the heat treatment, which moved to higher temperature with decrease in mole ratios of Ni2+/Fe2+ in the coating. XRD spectra confirmed that electroless Ni-Fe-P alloy deposits were amorphous in the as-plated condition, which transformed from the amorphous to crystalline phase with increase in calcining temperature. In addition, VSM data revealed that the resulting sample exhibited characteristics of soft magnetic materials at room temperature. The magnetic performances of the composites would be ameliorated with an increase in iron content in the coating and calcining temperature. (C) 2012 Elsevier B.V. All rights reserved.
Keywords:Electroless plating;Ni-Fe-P alloy;Fly ash cenospheres;Crystal structure;Magnetic properties