The Effect of Milling Time and Sintering Temperature on Crystallization of BaFe12O19 Phase and Magnetic Properties of Ba-Hexaferrite Magnet
G. Sadullahoğlu a, B. Ertuğ b, H. Gökçe b, B. Altuncevahir c, M. Öztürk d, R. Topkaya d, N. Akdoğan d, M.L. Öveçoğlu b and O. Addemir b
aBulent Ecevit University, Metallurgical and Materials Engineering Department, 67100, Zonguldak, Turkey
bIstanbul Technical University, Metallugical and Materials Engineering Department, 34469, Istanbul, Turkey
cIstanbul Technical University, Physics Engineering Department, 34469, Istanbul, Turkey
dGebze Institute of Technology, Department of Physics, 41400 Gebze, Kocaeli, Turkey
Received: April 2, 2014; In final form: June 15, 2015
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Barium hexaferrite samples were prepared by mechanical alloying using the stoichiometric amounts of BaCO3 and Fe2O3 precursors followed by heat treatment applied in the temperature range 700-1150°C. It was found that the high energy ball mill with a milling rate enabled to obtain powders with the finer particles at the reduced milling time mechanical alloying of the initial powders linked to the formation of barium hexaferrite phase. The exothermic reaction peaks corresponding to the formation of BaFe12O19 phase shift from 928°C to 793°C for the increased milling time up to 6 h. This was resulted in improved magnetic properties that the Ms value of the as-blended sample sintered at 800°C rised from 31.16 emu/g to 53.46 emu/g after milling for 6 h. The saturation magnetization and remanence values of the samples mechanically alloyed for 3 h and sintered at 1150°C also increased to 63.57 emu/g and 31.26 emu/g, respectively, more than for 800°C and 900°C. The increase in the annealing temperature favours the formation of BaFe12O19 phase in the samples.

DOI: 10.12693/APhysPolA.128.377
PACS numbers: 75.50.Vv, 75.60.Ej