Nanostructured nickel-iron-tungsten alloy coatings were electrodeposited from an ammonia citrate bath on steel and copper substrates at current densities in the range of 50 to 300 mA cm −2 . The contents of iron and tungsten in the alloy increase and that of nickel decreases with increasing deposition current density. At current densities below 100 mA cm −2 , smooth shiny coatings with no cracks and craters are deposited. Higher current densities result in matte coatings developing cracks and craters. XRD analysis showed that the coatings contain nanocrystals of FCC structured solid solution of iron and tungsten in nickel embedded in an amorphous matrix. Increasing deposition current density leads to an increase in the amorphous phase content and a decrease in both the content and mean crystallite size of the FCC phase. The coatings with an increased amorphous phase content and a decreased mean FCC crystallite size exhibit lower magnetization and reduced hardness. During annealing at temperatures up to 400 • C, the alloy undergoes structural relaxation along with short-range structural arrangement, resulting in increased magnetization and hardness. At temperatures above 500 • C, annealing leads to amorphous phase crystallization and crystal grain growth in the FCC solid solution, thus leading to reduction in both magnetization and hardness.
Ni96.7Mo3.3 powder was electrochemically obtained. An X-ray diffraction analysis determined that the powder consisted of a 20% amorphous and 80% crystalline phase. The crystalline phase consisted of a nanocrystalline solid nickel and molybdenum solution with a face-centred cubic (FCC) lattice with a high density of chaotically distributed dislocations and high microstrain value. The scanning electronic microscopy (SEM) showed that two particle structures were formed: larger cauliflower-like particles and smaller dendriteshaped ones. The thermal stability of the alloy was examined by differential scanning calorimetry (DSC) and by measuring the temperature dependence of the electrical resistivity and magnetic permeability. Structural powder relaxation was carried out in the temperature range of 450 K to 560 K causing considerable changes in the electrical resistivity and magnetic permeability. Upon structural relaxation, the magnetic permeability of the cooled alloy was about 80% higher than the magnetic permeability of the fresh powder. The crystallisation of the amorphous portion of the powder and crystalline grain increase occurred in the 630 K to 900 K temperature interval. Upon crystallisation of the amorphous phase and crystalline grain increase, the powder had about 50% lower magnetic permeability than the fresh powder and 3.6 times lower permeability than the powder where only structural relaxation took place
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