An investigation on effects of annealing on magnetic properties of Ni-Fe-W-S electrodeposited coatings in tri sodium citrate bath

Document Type: Regular Paper

Authors

1 Department of Physics, KSR College of Engineering, Tiruchengode-637215, Tamil Nadu, India

2 Department of Physics, Government College of Technology, Coimbatore-641001, Tamil Nadu, India

3 Department of Physics, Angel College of Engineering & Technology, Tirupur-641665, Tamil Nadu, India

Abstract

In the present investigation electrodeposited Ni-Fe-W-S nano crystalline thin films were prepared in tri sodium citrate bath at bath temperature of 40˚C. Annealing of the electro deposited thin film was performed at 200˚ C temperature for one hour. X-ray diffraction technique (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDAX), Vickers Hardness Test (VHN), and Vibrating Sample Magnetometer (VSM) were utilized to study the as-deposited and annealing effects on the structural and magnetic properties of the film. X-ray diffraction (XRD) result indicated that the as-deposited film had crystalline size of 31 nm. Annealing treatment of the coatings produced the enhanced crystalline size of 26.6 nm. Due to the improvement of soft magnetic properties in the 200˚C annealed film, the saturation magnetization is enhanced by 88 × 10-3 emu/ cm2 (coercivity decreased to 14.6 Oe) compared with the case of as-deposited film at bath temperature of 40˚C. The magnetic flux density (Bs) of the annealed film was enhanced by 0.6328 Tesla. Hardness of the annealed film increased from 143 VHN to 151 VHN. This shows that the soft magnetic properties of Ni-Fe-W-S thin films are greatly enhanced by annealing at 200˚C which can be used in MEMS applications.

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