本文選題：M型永磁鐵氧體 + 熔鹽法�。� 參考：《蘭州大學(xué)》2015年碩士論文

【摘要】：M型永磁鐵氧體作為一種重要的永磁材料被廣泛應(yīng)用到電子行業(yè)和重工業(yè)中,本文從離子替代和制備方法等方面對(duì)M型永磁鐵氧體的制備、結(jié)構(gòu)、形貌及磁性進(jìn)行了一系列的研究,主要涉及的工作有以下幾點(diǎn)：1.采用熔鹽法制備了Zn-Ti替代BaM磁粉,并研究了Zn-Ti替代量和不同助熔劑對(duì)Zn-Ti替代BaM磁粉的影響,我們發(fā)現(xiàn)HcJ的改變不只取決于Zn-Ti替代的量,晶粒的直徑厚度比也起到很重要的作用；B作為助熔劑的晶粒尺寸比A作為助熔劑時(shí)小很多,使HeJ也提高很多,隨著預(yù)燒溫度的升高,B作為助熔劑的晶粒長(zhǎng)大不明顯,都是在單疇尺寸以下,晶粒形貌呈現(xiàn)出較小的六角形片狀,而A作為助熔劑的晶粒明顯長(zhǎng)大,有些顆粒處于單疇尺寸以上,晶粒形貌呈現(xiàn)出較厚大的六角形塊狀。2.通過(guò)固相反應(yīng)法制備了La-Co替代的M型鐵氧體磁粉,實(shí)驗(yàn)結(jié)果說(shuō)明：增加La-Co替代SrM磁粉的鐵含量,對(duì)晶粒的長(zhǎng)大和直徑厚度比增大能起到一定的抑制作用,在相同預(yù)燒溫度下HcJ隨著鐵含量的增加而逐漸增大；在改變Ca-La-Co替代SrM磁粉的Ca含量的實(shí)驗(yàn)中,在相同預(yù)燒溫度下隨著鈣含量的增加,晶粒的尺寸逐漸增大,致使HcJ隨著鈣含量的增加而降低;少量的鋇添加到Ca-La-Co系M型鐵氧體磁粉中,能起到抑制晶粒長(zhǎng)大和減小晶粒的直徑厚度比的作用,可以顯著的提高HcJ。3.利用改進(jìn)的陶瓷工藝法分別制備了純SrM、La-Co替代SrM、Ca-La-Co替代SrM和Ca-La-Co系M型鐵氧體四種燒結(jié)永磁鐵氧體,典型結(jié)果分別為：SrM: Br=3.56 kGs, HcJ=2.63 kOe; La-Co-SrM:Br=4.09 kGs, HcJ=3.97 kOe Ca-La-Co-SrM:Br=3.90 kGs, HcJ=5.18 kOe; Ca-La-Co系M型鐵氧體：Br-=4.01 kGs,HcJ=4.69 kOe。能看出：La-Co替代可以顯著的提高SrM的Hcj, Ca-La-Co系M型鐵氧體的HcJ比La-Co-SrM有所提高,Ca-La-Co-SrM更是得到了5.18 Oe的高值,經(jīng)過(guò)離子替代的Br比純SrM要高,但是Br總體水平并不高,這主要是因?yàn)槎渭?xì)磨的粒度分布不均勻,使取向度無(wú)法提高。4.通過(guò)對(duì)燒結(jié)永磁鐵氧體的制備工藝進(jìn)行調(diào)節(jié),結(jié)果表明：在預(yù)燒時(shí)添加Co元素的Br比二次球磨時(shí)添加高一些,但是預(yù)燒時(shí)產(chǎn)生的低矯頑力鉆鐵氧體,使最終燒結(jié)體的HcJ降低,并且J的退磁曲線出現(xiàn)斜率較大的陡降現(xiàn)象；二次細(xì)磨的時(shí)間延長(zhǎng)使顆粒尺寸減小,提高HcJ,但是細(xì)小顆粒增多造成粒度分布不均勻,降低了Br,繼續(xù)延長(zhǎng)細(xì)磨時(shí)間能夠改善粒度分布情況,提高磁場(chǎng)取向效果,可以在提高HcJ的同時(shí)又不會(huì)過(guò)多的降低Br。5.利用較細(xì)的Fe2O3為原料采用固相反應(yīng)法,能夠得到晶粒尺寸小且分布均勻的預(yù)燒粉,這種預(yù)燒粉能使La-Co替代SrM燒結(jié)永磁鐵氧體的剩磁Br和內(nèi)稟矯頑力HcJ同時(shí)得到提高,又可以大大減小二次細(xì)磨的時(shí)間,提高效率,典型的磁性能為：Br=4.28kGs、HcJ=4.30kOe、(BH)max=4.32MGOe。
[Abstract]:M type permanent magnet ferrite, as an important permanent magnet material, has been widely used in electronic industry and heavy industry. In this paper, the preparation and structure of M type permanent magnet ferrite have been studied from the aspects of ion substitution and preparation methods.A series of studies have been carried out on morphology and magnetism, mainly involving the following points: 1. 1.Zn-Ti instead of BaM magnetic powder was prepared by molten salt method. The effects of Zn-Ti substitution amount and different flux on the substitution of Zn-Ti for BaM magnetic powder were studied. We found that the change of HcJ is not only dependent on the amount of Zn-Ti substitution.The grain size of B as flux is much smaller than that of A as flux, which makes HeJ increase a lot. With the increase of temperature, the grain size of B as flux is not obvious.All of them are below the single domain size, and the grain morphology shows a smaller hexagonal shape, while the grain size of A as flux grows obviously. Some grains are larger than single domain size, and the grain morphology shows a thicker hexagonal block.M-type ferrite magnetic powder replaced by La-Co was prepared by solid state reaction. The experimental results show that increasing the iron content of La-Co instead of SrM magnetic powder can inhibit the grain growth and the increase of the ratio of diameter and thickness to a certain extent.In the experiment of changing the Ca content of Ca-La-Co instead of SrM magnetic powder, the grain size increases with the increase of calcium content at the same pre-firing temperature.The addition of a small amount of barium to the Ca-La-Co system M-type ferrite magnetic powder can inhibit grain growth and decrease the ratio of diameter and thickness of grain, and can significantly increase HCJ.3.Four kinds of sintered permanent magnet ferrites were prepared by using the improved ceramic process. The typical results were as follows: Br=3.56 KGs, HcJ=2.63 KOe; La-Co-SrM:Br=4.09 KGs, HcJ=3.97 kOe Ca-La-Co-SrM:Br=3.90 KGs, HcJ=5.18 KOe; Ca-La-Co M ferrite: Br-4.01 KGsHcJ 4.69 kOe.It can be seen that the substitution of% La-Co can significantly improve the HCJ of SrM. The HcJ of M-type ferrite in Ca-La-Co system is higher than that of La-Co-SrM, and the higher value of 5.18 Oe is obtained. The Br replaced by ion is higher than that of pure SrM, but the overall level of Br is not high.This is mainly due to the second fine grinding particle size distribution is not uniform, so that the degree of orientation can not be improved. 4.By adjusting the preparation process of sintered permanent magnet ferrite, the results show that the Br of adding Co element during pre-sintering is higher than that of secondary ball milling, but the low coercivity ferrite produced during pre-sintering reduces the HcJ of the final sintered body.In addition, the demagnetization curve of J has the phenomenon of steep drop with a large slope, and the prolongation of the time of secondary fine grinding reduces the particle size and increases HCJ, but the increase of fine particles results in uneven particle size distribution.With the decrease of Br., the particle size distribution can be improved by prolonging the fine grinding time, and the effect of magnetic field orientation can be improved, and the HcJ can be improved and the Br.5can not be reduced too much at the same time.The pre-fired powder with small grain size and uniform distribution can be obtained by solid state reaction with fine Fe2O3 as raw material. The remanent magnetic remanence Br and intrinsic coercivity HcJ of La-Co instead of SrM sintered permanent magnet ferrite can be improved simultaneously.The time of secondary fine grinding can be greatly reduced, and the efficiency can be improved. The typical magnetic properties are as follows: 1: Br-4.28kGsHcJ (4.30kOE) BHHmax (4.32MGOE).
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TM277

【共引文獻(xiàn)】

相關(guān)博士學(xué)位論文 前6條

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3 崔月梅;新型吸附材料的合成及其對(duì)水和生物樣品中痕量元素吸附性能的研究[D];蘭州大學(xué);2008年

4 劉穎;摻雜M-型鋇鐵氧體的制備及磁學(xué)性能研究[D];哈爾濱工程大學(xué);2007年

5 鄒小軍;新型吸附材料的合成及其對(duì)痕量金屬離子的富集分離研究[D];蘭州大學(xué);2009年

6 傅小明;穩(wěn)恒磁場(chǎng)下制備鐵氧體材料的基礎(chǔ)研究[D];上海大學(xué);2010年

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