Study on the effect of CaO addition on micro structure and magnetic properties of BaFe12O19 made using powder metallurgy technique

Abstract

The Ba-ferrite (BaO.6Fe2O3) has been made by using powder metallurgy technique with addition 0 %, 0,25% and 0,50 %wt. of CaO. The raw materials used in the experiment were BaCO3, Fe2O3 and CaCO3, then they were weighed according to above composition and further the all raw materials were wet milled in rotary ball mill for 12 hours, in this case, aquadest was used as milling media. After milling process, the slurry sample was sieved to remove excess of water, then it was dried at 100°C for 6 hours. The next stage of the process is the calcination process of the dried powder at temperature 1050°C using electrical furnace with 2 hours of holding time. The powder sample which has been calcined was formed into a pellet using a hydraulic press with a pressure of 40MPa, then the pellet sample was sintered using an electric furnace at 1150 with a retention time of 2 hours and the heating rate was 10°C /minute. The effect of addition CaO by 0.25% wt. can provide an increase in magnetic properties and changes in the size of Sr ferrite crystals. In this composition, obtained Ba-ferrite magnet with remanence value = 38 emu/g, coercivity value = 2950 Oe, flux magnetik = 580 Gauss and crystal size = 687nm.