Characterization of nano-composite Ni dispersed over a silica matrix prepared by a modified sol-gel technique

• Structural characteristics for silica gel doped with Ni and NiO, prepared by sol-gel method, using tetra-ethoxysilane as precursor material and submitted to different thermal treatment temperature, were investigated through XRD and FTIR, while their morphology through SEM and TEM. The pure silica gel samples heat treated in the range between 60C up to 700C have an amorphous phase, while crystalline phase appears at 400C after annealing of the doped samples in hydrogen gas at 400C. Measurements of crystallite size of 30 mol % Ni ions dispersed over the amorphous silica matrix sintering at heat treatment temperature 250C gave rise to a final sample its XRD pattern is characterized by broad Ni peak profiles, corresponding to particle size of 11.8 nm as determined by using the win fit program after reduction in hydrogen at 400C for 4 hours. Analysis the obtained FTIR spectra, indicates that the sol-gel process used for synthesizing the nano-composites was successful for the entire samples. The hysteresis loops were measured to determine saturation magnetization (Ms), remnant magnetization (Mr) and coercivity (Hc). From these data, it was found that the saturation magnetization for Ni increases, while the coercive field values decrease, by increasing Ni content.

Nyckelord

FTIR; Hysteresis loop; Nano-composite; Ni; Silca gel; Sol gel; XRD

TECHNOLOGY

TEKNIKVETENSKAP

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