Development Of Low Core Loss Mn-Zn Power Ferrites Apply In Wide Temperature Range

Low loss Mn Zn power ferrites used in a wide temperature range were prepared by conventional oxide ceramic process.This material has low loss not only at some special temperature range,but also at wide temperature range,which results in lowering stand-by power consumption and easily working in high and low temperature.The effects of compositions and additives on magnetic properties,temperature characteristics and reliability were studied.(1)Both the addition of Fe2O3 and Zn O affect magnetic properties for Mn Zn ferrites.First,when Zn O content was constant,the influences of adding simple Fe2O3 were discussed.The results show that with the increase of Fe2O3 content,saturation magnetic flux density(Bs)rises slowly,permeability(?i)first increases then decreases,magnetic loss Pcv first reduce again rise,and the bottom temperature for magnetic loss decreases effectively.While Fe2O3 content reached 53.15 mol%,in a wide temperature ranging from 0? to 100?,Pcv remained at about400 kw/m 3(100 k Hz,200 m T),thus having a good performance at wide working temperatures.Second,while Fe2O3 content was constant,the amount of Zn O was altered continuously.It was found that with the increase of Zn O content,?i first upgrades then drops,whereas Pcv firstincreases then decreases.(2)Co2O3 additive has an influence on temperature characteristics for Mn Zn ferrite.With the rise of Co2O3 additive,the loss temperature trend line leveled off,correspondingly.The best loss temperature characteristic for samples can be obtained when Co2O3 content is added up to 4000 ppm.(3)Ti O2 plays a significant role on the reliability for Mn Zn ferrites.Along with the increase of Ti O2 content,the changing rate for Pcv and?ifor sample put at 200 ? holding for 96 h declined gradually,respectively.Ultimately,the rate for Pcv is less than 5% with the 2000 ppm Ti O2 content.Through the main formula adjustment and selection of additives,wide temperature and low loss Mn Zn ferrites with high reliability were prepared.The main performance indices are as follows: When the temperature ranges from-20 ? to 100 ?,Bs reaches 460 m T(1194A/m),and Pcv is less than 330 k W/m3(100 k Hz,200 m T).