A ferromagnetic and supersaturated fcc Fe5lCu49 solid solution has been obtained by mechanical alloying. After subsequent thermal treatments the fcc phase undergoes a spinodal decomposition which finally, at 780 K, yields a mixture of fcc and bcc phases. In this work, a systematic magnetic study is carried out on samples at diferent decomposition states in order to determine the process of transformation into the stable phases. We observe a 20% maximum diminution on the magnetic moment with increasing temperatures of the thermal treatment. The Mossbauer spectrum taken at 8 K shows that 20% of the Fe atoms are in a nonferromagnetic state. On the other hand, upon heating up to 723 K the roomtemperature coercive field increases dramatically to 640 Oe, and after cooling down to 10 K it decreases to 270 Oe. Deviations from the T law in the temperature dependence of the magnetization have been observed. This behavior is explained by fluctuations in composition due to the spinodal decomposition, which lead to fluctuations of the magnetic order parameters, i.e. , magnetic moment and Curie temperature.

Ni-Co/SiO 2 nanocomposite coating was deposited on the steel substrate by pulse electrodeposition method. The coatings were characterised by X-ray diffraction, field emission scanning electron microscopy technique, energy-dispersive X-ray spectroscopy and X-ray map (dispersive elemental mapping) analysis. The influences of stirring rate, pH and SiO 2 concentration parameters on the mechanical properties and corrosion resistance were studied. The zeta potential of SiO 2 nanoparticles was decreased by mounting the pH and also adsorption of the surfactant SDS. Microhardness, friction coefficient, wear and anodic polarisation were determined through Buhler microhardness tester, pin-on-disc wear test and potentiostat galvanic device, respectively. By applying optimum electrodeposition condition (stirring rate 200 rev min −1 , pH 4.6 and SiO 2 concentration 20 gL −1 ) incorporation of SiO 2 particles into the nickel-cobalt matrix increases which results in the preparation of coatings with high microhardness and corrosion resistance, low friction coefficient and wear mass loss.

Ni-Co/SiO 2 nanocomposite coatings and Ni-Co alloy coatings were prepared on steel substrate using direct and pulse electrodeposition methods. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), X-ray map and energy dispersive X-ray spectroscopy (EDX) were employed to investigate the phase structure, surface morphology, and elemental analysis of coatings, respectively. In high discharge rates, the surface morphology was rough, disordered and gross globular; on the contrary, in the low rates, it was smoother, more ordered and fine globular. Also, effect of electrodeposition parameters such as average current density, pulse frequency and duty cycle on the microhardness and grain size of nanocomposite coatings that produced through the pulse current electrodeposition method have been investigated. By amplifying both duty cycles up to 50% and average current density from 2 to 6 A dm −2 , microhardness increased, while the grain size decreased. But when duty cycle mounted on more than 50% and the average current density went up to 8 A dm −2 , microhardness lessened, while the grain size rose. The optimum value for pulse frequency was about 25 Hz. Results showed that microhardness of nanocomposite coatings which were produced by pulse current method was higher than that of produced by direct current method.

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