• Maricic, Aleksa
• Spasojevic, Miroslav
• Ribic-Zelenovic, Lenka
• Spasojevic, Pavle
• Cirovic, Natasa

Abstract

<jats:p>Nanostructured nickel-iron-tungsten alloys were produced by electrodepositionfrom an ammoniacal citrate bath. The tungsten content of the alloy rangedfrom 0.8 wt.% to 11 wt.%, and the crystal grain size of the FCC phase of thesolid solution of iron and tungsten in nickel was between 14 nm and 3.3 nm.The amorphous phase content of the alloy increases with decreasing crystalgrain size. As the amorphous phase content increases, the magnetization,electrical conductivity and hardness of the alloy decrease. Annealing thealloy to crystallization temperature results in structural relaxation duringwhich the alloy undergoes short-range ordering in conjunction with decreasesin the density of chaotically distributed dislocations and internalmicrostrain level, which increases the exchange integral value, theelectronic density of states at the Fermi level, the mean free path ofelectrons, the ordering and the mean size of cluster in the sliding planeand results in more uniform orientation of dipole moments of certainnanoparticles. These changes: a) increase the mobility of magnetic domainwalls, facilitate the orientation of domains in the external magnetic fieldand cause an increase in magnetization; b) cause a decrease in electricalresistance, and c) impede the sliding of grain boundaries and increase thehardness of the alloy.Annealing the alloys at temperatures above 400?Cresults in amorphous phase crystallization and larger crystal grains of theFCC phase, along with a decrease in the density of chaotically distributeddislocations and a decrease in internal microstrain level.The formation oflarger crystal grains reduces the hardness of the alloy, decreases itsspecific electrical resistance and impedes both the orientation of certainmagnetic domains and the shift of walls of already oriented domains, thusinducing a decrease in magnetization.The heat released during the millingof Ni87.3Fe11.3W1.4 alloy with FCC-phase crystal grains 8.8 nm in averagesize causes amorphous phase crystallization, FCC crystal grain growth and anincrease in magnetization.Alloys with relatively high tungsten content (11wt. %) have an inhomogeneous composition, a high proportion of the amorphousphase and FCC crystal grains with an average size of 3.3 nm. Thismicrostructure results in magnetic domains that have different andrelatively low thermal stabilities and relatively low degrees ofmagnetization.</jats:p>

Topics

• density
• cluster
• amorphous
• grain
• nickel
• grain size
• phase
• mobility
• hardness
• dislocation
• iron
• annealing
• tungsten
• magnetization
• electrical conductivity
• crystallization
• grain growth
• crystallization temperature
• tungsten alloy