Abstract
Single phase Ba-Pr-Co M-type ferrite fine particles were prepared by controlling the chemical coprecipitation method and subsequent heat treatment. The chemical reagents used for this experiment were BaCl2·2H2O, FeCl3·6H2O, PrCl3·7H2O and CoCl2·6H2O. The chemical coprecipitation compositions were chosen according to the formula {(BaO)·n/2(Fe2O3)}100−x−y(Pr2O3)x(CoO)y, where n was fixed at 10.5, x was varied between 1.0 and 12.0, y between 2.0 and 10.0. A water solution containing Ba2+, Fe3+, Pr3+ and Co2+ was poured into a solution of NaOH (pH=13.0). The precipitated products were boiled at 100°C for 2h, and they were carefully washed with pure water for 24h. The washing was repeated 5 times and the products were then filtered and dried at 80°C for 12h. The obtained fine particles were heated at a temperature between 950 and 1100°C for 2h in air to get single phase Ba-Pr-Co M-type ferrite fine particles. The most prominent magnetic properties have been observed for the sample with the preparation composition of {(BaO)·5.25(Fe2O3)}92.0(Pr2O3)4.0(CoO)4.0 ; they are as follows: σs=83.1×10−6 Wb·m/kg (66.1 emu/g), σr=41.0×10−6 Wb·m/kg (32.6 emu/g), HcJ=467.8 kA/m (5.88 kOe), α(σr)=−0.19 %/°C, α(HcJ)=0.07 %/°C and Tc=450°C.
