Effects of solid-state reaction temperature on the activation energy and DC-bias superposition of NiCuZn ferrites based on master sintering curve

Abstract

This work reports our recent studies on the microstructure and properties of NiCuZn ferrites, with particular interests in effects of solid-state reaction temperature on the sintering activation energy and DC-bias superposition characteristic. The theory of master sintering curve was used to investigate the densification evolutions of NiCuZn ferrites during sintering process. Experimental results demonstrated that materials with solid-state reaction temperature of 850°C exhibited the lowest value of activation energy, 577.6 kJ mol −1 . When the solid-state reaction temperature was lower than 800°C, reaction could not be perfectly completed, which would hinder the consolidation process during heating up. In addition, increased solid-state reaction temperature could facilitate the homogeneous grain growth, reduce the final grain size and improve DC-bias superposition characteristic. Possible mechanisms behind are discussed.

Investigation on the micro-structure and magnetic properties of LMZBS-Bi2O3 doped low-temperature sintered NiCuZn ferrites

“…Here, all the NiCuZn ferrites had the same composition, therefore, the value of Ms was dependent on the density. A dense microstructure could promote NiCuZn ferrite to exhibit outstanding magnetic performances [27]. As a result, Ms and density exhibited the same variation trend.…”

“…It also can be seen from the figure 6(b) that the Ms increased rapidly and then decreased with the increasing addition of LMZBS-Bi 2 O 3 . It has been reported that Ms was closely related to the composition and density [23,27]. Here, all the NiCuZn ferrites had the same composition, therefore, the value of Ms was dependent on the density.…”

“…As a result, all the samples exhibited a relatively high Pcv value under the frequency of 500 KHz. NiCuZn samples with dense microstructure and high density could exhibit the low Pe and Pr [27][28][29]. Therefore, combining the results shown in figures 4 and 5, the 0.2 wt% LMZBS-0.3 wt% Bi 2 O 3 doped NiCuZn ferrite exhibited the lowest Pcv under different induction conditions and different frequencies.…”

“…LMZBS(0.2wt%)-Bi 2 O 3 (0.3wt%) doped NiCuZn synthesized in this work exhibited the highest Ms and permeability among all the samples. Based on the above analysis shown in figures 4-9, the reason may be lie in that appropriate amount of LMZBS-Bi 2 O 3 as dopant could promote NiCuZn to possess a uniform grain size and dense micro-structure [27,36].…”

Progress in materials and processes of multilayer power inductors

“…Lowering the sintering temperature by adding sintering aids is the most effective and least expensive technique. The low sintering temperature (below 900 °C) and the magnetic properties of NiCuZn ferrites with the addition of Bi 2 O 3 have been extensively studied [7,[11][12][13][14]. The shrinkage behaviors of the NiCuZn ferrites with submicron size added with various amounts of Bi 2 O 3 are shown in Fig.…”