Mnzn Ferrite Mechanical Properties Study

In this dissertation,high permeability Mn-Zn ferrite materials were prepared by oxide ceramic technics. The influences of main composition, the calcining technics, the additives, the second ball-milling process and the sintering technics on MnZn ferrites were deeply investigated. MnZn ferrites with high density,high permeability,high saturation magnetic induction and excellent mechanical performance were prepared.As the results showed: with the increase of Fe2O3 from 51mol% to 54mol%, bending strength and Vickers hardness(Hv)raise,μi raises initially and then declines, and Bs raises, but density has little change. With the increase of ZnO from 15mol% to 23mol%, bending strength and Hv raise,μi raises initially and then declines, Bs declines and density raises. Raising the calcining temperature can decline the activity of the powder, with the raise of calcining temperature from 800℃to 1000℃, grain size become smaller, bending strength and Hv raise,μi and Bs raise initially and then decline. With the increase of holding time from 1h to 6h, activity of the powder decline, mechanical and magnetic performance raise initially and then decline, but density has little change. Appropriate addition of V2O5, MoO3 and Bi2O3 could promote liquid-phase sintering and grain growth, then improve micro-morphology, mechanical and magnetic properties, but excessive addition could restrain grain growth, then decline the performance of MnZn ferrites. Under the condition which are ball: powders: dispersant=2: 1: 1.5 and rotating speed is 196 r/min, milling time is 2h, the activity of powder is optimal, then improve mechanical and magnetic properties. With the raise of the forming pressure from 40KN to 100KN, density and mechanical propoties raise. With the raise of the sintering temperature from 1360℃to 1420℃, magnetic properties and density raise initially and then decline.