The Study Of Tunable Soft Magnetic Properties And The Low-temperature-sintered Of Substituted Barium Ferrites

The M-type barium ferrite has some advantages like large coercivity andlarge energy product and uniaxial magnetic anisotropy eTc. They have beenwidely used in the field of permanent, microwave absorbing and microwave andmillimeter wave devices. The investigation has focused on the new synthesismethods、modification and sintered in lower temperature on the characters inorder to obtain good performance M-type barium ferrite. In this paper, we triedto improve the overall performance of BaM ferrite by three ways: substitutingCo-Zr and Mn-Co-Zr ions, changing chelator and adding sintering aid. Theproperties of powder and sintered ferrite ceramic samples were characterized byX-ray diffraction (XRD), scanning electron microscope (SEM), IR spectra,TG-DTA, VSM and vector network analyzer respectively. Here are the results.In the ions substituting and sintering process aspect，the substituting Co-Zrand Mn-Co-Zr ions can effectively adjust magnetic of BaM ferrite magnetic. theformer are adjusting coercivety Hc to the range from5003Oe to136Oe, whilethe latter can obviously increase saturation magnetization Ms of BaM ferrite,when x=0.4, Its peak reaches to67emu/g, with dosage increasing,the decreasingof its size reduced; Compared with Co-Zr ions doping, the high-frequencypermeability of Mn-Co-Zr ions substituting BaM ferrite increase more obviously.with the increasing of the x content, dielectric properties under the highfrequency slight changed and the cut-off frequency are significantly decreasing.when set anhydrous ethanol as the ball milling agent, the best presinteringtemperature is1000℃, ball milling time is8h, the density、grain morphologyand magnetic properties of BaM ferrite ceramics are the best.The BaM ferrite was prepared with carbohydrate as complexing agentinstead of citric acid, and the sintering property was studied. It was indicated thatthe same quality of BaM ferrite was obtained with less comsumption ofcarbohydrate than that of citric acid. The glucose was the most conducive toincrease the saturation magnetization of BaM ferrite powder, and the saturationmagnetization of sample P0-1100reached to62.5emu/g. The sucrose was favorof improving the soft magnetic properties of BaMn0.5Co0.5Zr1.0Fe10O19powder, but the saturation magnetization was low. The starch was the most conducive toincrease the magnetic property of BaFe12O19, and the coercivity of sample D-850was5254Oe. The starch was the optimal complexing agent to keep the magneticproperty of BaFe12O19in the aspect of BaM ferrite sintering. However, thesaturation magnetization and density of sample was lower than that of glucose asthe complexing agent. The sucrose was favor of decreasing the coercivity ofBaMn0.5Co0.5Zr1.0Fe10O19ceramics.In low-temperature sintered of M type barium ferrite aspect, the ZBSadditives efficiently lowered the sintering temperature of P0ceramics below950℃and P1.0ceramics (1050℃). It was defined that5wt%ZBS content wasappropritate to give attention to both low-fired charateristic and good magneticproperties.5wt%B2O3content can effectively enhance sintering density of P0ceramic, but its magnetic properties decreasing is the most obvious. P0ceramicsadding5wt%CBS sintered at low temperature comprehensive performance thatis the best, but not conducive to the soft magnetization of doped P1.0sample...