Sintering of Ni-Zn ferrite nanopowders by the constant heating rate (CHR) method

Abstract

The constant heating rate method employed in sintering studies offers several advantages over the isothermal method, particularly the fact that all the parameters that describe the sintering phenomena can be obtained from a single sample. The purpose of this work is to determine the parameters of sintering kinetics of nanosized Ni-Zn ferrite powders synthesized by combustion reaction. The nonisothermal sintering method was studied using a constant heating rate (CHR). The Ni-Zn ferrite powders, with average particle size varying from 18 nm to 29 nm, were uniaxially pressed and sintered in an horizontal dilatometer at a constant heating rate of 5.0 °C/min from 600 °C up to complete densification, which was reached at 1200 °C. The compacts were characterized by scanning electron microscopy (SEM). Experimental results revealed three different sintering stages, which were identified through the Bannister Theory. The shrinkage and the shrinkage rate analyzed showed a viscous contribution in the initial sintering stage, which was attributed to the mechanism of structural nanoparticle rearrangement

XRD, magnetic and Mössbauer spectral studies of nano size aluminum substituted cobalt ferrites (CoAlxFe2−xO4)

“…Such an increase has also been observed by various workers [15,16]. It is widely believed that the net decrease in free energy of solid-solid and solid-vapor interface provides the necessary driving force for particle growth during annealing process [17]. SAED of the annealed particle shown in the inset of Fig.…”

Cation Distribution in Lithium Ferrite (LiFe5O8) Prepared via Aerosol Route

“…The micrographs for sample annealed at 1200 o C shows that the particle size increases with annealing temperature. It is widely believed that the net decrease in free energy of solid-solid and solid-vapour interface provides the necessary driving force for particle growth during annealing process [15].…”

Temperature dependent elastic properties of nanocrystalline Co1−Zn Fe2O4

“…4 O] were dissolved in de-ionized water. An aqueous NaOH was added dropwise to the solution until pH $ 13 was obtained.…”

“…This is mainly because they have some unique properties which are not shown by the bulk crystalline materials [3][4][5]. Cobalt zinc ferrite is one of the promising soft ferrites used in electronic devices such as transformer cores, electric motors and generators.…”