The Effects Of LaCoZn Doping And Additives On The Magnetic Properties Of Strontium Ferrite

As the most widely used magnetic materials, permanent ferrite is the important part ofelectronic devices, automobiles, household appliances, computers and other products.With the trends of smaller, lighter and easier to carry for electronic, manufacturers alsohave higher requirements to the performance of permanent ferrite. In general, the ionsubstitute and adjusting additives etc. can improve the performance of ferrite.In this thesis, strontium ferrite was prepared by solid state reaction. The experimentswere divided into two parts with the sector of prefire: the material preparing of LaCoZnsubstitute strontium ferrite Sr_0.7La_0.3Fe_11.3Co_xZn_0.3-xO₁₉and the influences of normaladditives in strontium ferrite. XRD、SEM、VSM and magnetic properties tester were usedto research magnetic properties of Sr_0.7La_0.3Fe_11.3Co_xZn_0.3-xO₁₉varying doping quantity x,prefire temperature T and soaking time t. Performance of ferrite varying the weight ratioof each additive used by the experiments was also studied. The conclusions were asfollow:1、Doping quantity x and prefire temperature T extremely affected the specificsaturation magnetizationσs and intrinsic coercively H_cjof Sr_0.7La_0.3Fe_11.3Co_xZn_0.3-xO₁₉.Ingeneral, with the rising of x,σs decreased at first and increased fast when x>0.2, H_cjshows the opposite tendency.With the rising of T,σs increased and H_cjdecreasedcontinuously. Besides, soaking time t had the same influence onσs and H_cjcomparedwith T. However, it changed slowly.2、CaCO₃can increase remanence Brby increasing the density of strontium ferrite,and slightly decrease intrinsic coercive force H_cj. When the weight ratio is more than0.8%, H_cjwould be decreased. SiO₂can rapidly increase H_cj. But when the weight ratio ismore than0.3%,H_cjwill decrease.Brwas a monotonous decrease of the weight ratio.Cr2O₃can improve H_cjand reduce Br, but when the weight ratio is more than0.3%, H_cjalsodecreased.H3BO₃can increase H_cjcontinuously in and not affect Br. Small amount of CoO_<sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub> can improve H_cj, but when the weight ratio is more than0.2%, H_cjwill have a sharpfall.Brwas slightly damaged by CoO.