Effects of Nb2O5, TiO2, SiO2, and CaO additions on the loss characteristics of Mn-Zn Ferrite

Abstract

The effects of SiO 2 , CaO, TiO 2 , and Nb 2 O 5 additives on the high-frequency magnetic properties of the Mn 0.3 Zn 0.7 Fe 2 O 4 (MZFT) ferrites were examined in this study. The content of SiO 2 and CaO was kept at 50 ppm and 500 ppm, while that of TiO 2 and Nb 2 O 5 varied respectively from 0 to 3000 ppm and from 0 to 300 ppm. All samples surpassed 95 % theoretical density after sintering at 1300°C with N3T30 composition (50 ppm SiO 2 , 5000 ppm CaO, 3000 ppm TiO 2 , and 300 ppm Nb 2 O 5 ) reporting the highest sintered density. The calculated lattice constants of the ferrites evaluated appeared to be nearly the same (≈0.849 Å) and no second phase was present. It was apparent that the additions of SiO 2 , CaO, TiO 2 , and Nb 2 O 5 exerted no notable impact on the microstructures of the ferrites. The average grain size of the samples sintered at 1300°C ranged from 7.78 μm to 9.76 μm with both intergranular and intragranular pores. Incorporation of partial Ti 4+ and Nb 5+ ions into the lattices shifted the secondary maximum peak of the μ i -T curves from 90°C to lower temperatures (60 to 70°C). The initial permeability of the ferrites was strongly dependent on the additives and the sintering temperature. The initial permeability of the MZFT sample sintered at 1275°C and 1300°C read respectively 5056 and 5222, and that of the N3T30 sample emerged to be 2917 and 3389. Compared to that of pure MZFT ferrite, the TiO 2 and Nb 2 O 5 , SiO 2 and CaO added compositions displayed a nearly 45 % reduction in total power loss, mainly caused by the electrical insulating layers at the grain boundaries, which lowered the eddy current loss. The N3T30 ferrite sintered at 1275°C showed the lowest total power losses of 272 mW/cm 3 at 50°C.

Synergistic effect of V2O5 and Bi2O3 on the grain boundary structure of high-frequency NiCuZn ferrite ceramics

“…Since μ i reaches the maximum value when doped with 800 ppm V 2 O 5 and 800 ppm Bi 2 O 3 , P h also attains its optimal value unsurprisingly. P e is proportional to the square of the grain size and inversely proportional to the electrical resistivity [18,19]. Now that all the samples possess a small grain size of approximately 1 μm, the variation in P e can be ascribed to the fluctuating electrical resistivity.…”

“…The residual loss that originates from magnetic domain-wall resonance is bound up with microstructure, especially grain size, since the domain structure in a single crystalline grain could transform from a multidomain regime to a monodomain regime with a reduced grain size [15][16][17]. Meanwhile, further suppression of eddy-current loss could be achieved by refining the grain structure [18,19].…”

A review on MnZn ferrites: Synthesis, characterization and applications

“…In this method toxic and expensive organic solvents are not used in the reaction and all the materials used to synthesize MnZn nanoparticles are easily available and cost effective. The synthesis process is performed at room temperature under atmospheric pressure which is facile and economic.Many researchers synthesized MnZn ferrites by using this method [30,132,134,190]. The raw materials MnCO 3 , ZnO and Fe 2 O 3 in the proper weight were powdered and the powdered samples were calcined at 1100℃ for 5h in air atmosphere using muffle furnace with heating rate of 10℃/min and a cooling rate of 5℃/min.…”

“…In the class of soft ferrites, MnZn ferrites are preferred due to high permeability [122][123][124][125][126][127], saturation induction [128][129][130], low power losses [34,[131][132][133][134][135][136][137][138] and high magnetic induction [139,140]. MnZn ferrites are of great interest due to their wide range of applications such as hyperthermia applications [141], power applications [109][110][111], magnetic fluid [145], high frequency power supply, memory storage devices, TV sets, biomedicines [146], magnetic resonance, catalysis etc.…”

Measuring and modeling broadband magnetic losses versus temperature and aging effects in CoO-doped Mn-Zn ferrites

“…The preparation of the investigated ferrite specimens included the solid state processing of selected high-purity raw materials following the proportion of 0.487 mol % Fe2O3, 0.421 mol % MnO and 0.092 mol % ZnO, which were weighed, mixed and prefired at 850 0 C in air. Certain additives, such as CaO and Nb2O5 were pre-selected [8,9], while CoO addition varied between 0 and 6000 ppm. The 3000 ppm CoO-doped ferrite, which shows the best stability of the magnetic properties versus temperature, was then enriched by TiO2 = 1000 and 5000 ppm.…”