發(fā)布時(shí)間：2018-04-23 20:35

  本文選題：錳鋅鐵氧體 + 沸騰回流法��； 參考：《華南理工大學(xué)》2010年碩士論文

【摘要】： 納米磁性材料是當(dāng)今磁性材料研究的熱點(diǎn),軟磁材料中品種最多、用量最大、應(yīng)用最廣泛的是軟磁鐵氧體材料。納米錳鋅鐵氧體材料作為一種重要的軟磁材料具有廣闊的應(yīng)用前景。本文對(duì)納米軟磁錳鋅鐵氧體粉體的制備方法及性能進(jìn)行了研究。 本文采用沸騰回流法,以δ-FeOOH為前驅(qū)體,直接合成了尖晶石結(jié)構(gòu)的MnZn鐵氧體納米粉體。研究了共沉淀pH值、反應(yīng)時(shí)間等工藝因素對(duì)產(chǎn)物的影響,得出了合適的共沉淀沸騰回流法制備工藝；采用XRD、TEM、VSM等測(cè)試手段對(duì)產(chǎn)品進(jìn)行了表征,對(duì)回流相轉(zhuǎn)化反應(yīng)動(dòng)力學(xué)、熱力學(xué)、反應(yīng)機(jī)理、磁性能等進(jìn)行了分析研究。研究表明,通過(guò)調(diào)節(jié)pH值和回流時(shí)間可以得到從小于10nm到大于20nm不同粒徑的錳鋅鐵氧體粉體,獲得完全產(chǎn)物的最佳回流時(shí)間為6h。pH值對(duì)反應(yīng)劇烈程度及磁性能有很大影響,共沉淀pH值為13.0左右時(shí)獲得的制備態(tài)納米粉末尺寸約為20nm,飽和磁化強(qiáng)度達(dá)46A.m2/kg。 為了抑制納米粉體的團(tuán)聚,將物理分散與化學(xué)分散結(jié)合起來(lái),利用物理手段解團(tuán)聚,然后加入分散劑實(shí)現(xiàn)顆粒的穩(wěn)定化,可以達(dá)到較好的分散效果,得到了具有良好分散性的錳鋅鐵氧體納米粉體。 本文還研究了稀土元素(La、Nd、Gd)取代對(duì)尖晶石鐵氧體結(jié)構(gòu)和磁性能的影響。當(dāng)稀土離子取代尖晶石鐵氧體晶格中的Fe3+時(shí),稀土離子可能會(huì)進(jìn)入尖晶石晶格,也可能形成化合物進(jìn)入晶界。經(jīng)研究發(fā)現(xiàn)由于稀土離子(La3+、Nd3+、Gd3+)的有效磁距與離子半徑的差異,稀土離子的摻入會(huì)減少尖晶石鐵氧體的晶格常數(shù)和晶粒尺寸,而其矯頑力Hc得以提高,飽和磁化強(qiáng)度變化與稀土離子的添加量有關(guān)。
[Abstract]:Nanomagnetic materials are the research hotspot of magnetic materials at present. The soft magnetic materials are the most widely used in the field of soft magnetic materials, and the most widely used materials are the soft magnetic ferrite materials. Nanocrystalline manganese zinc ferrite as an important soft magnetic material has a broad application prospect. In this paper, the preparation method and properties of nanometer soft magnetic manganese zinc ferrite powder were studied. In this paper, MnZn ferrite nanocrystalline powders with spinel structure were synthesized by boiling reflux method with 未 -FeOOH as precursor. The effects of coprecipitation pH value, reaction time and other technological factors on the product were studied, and a suitable preparation process by co-precipitation boiling reflux method was obtained, and the product was characterized by XRDX TEM VSM, and the reaction kinetics and thermodynamics of the reflux phase conversion reaction were also studied. The reaction mechanism and magnetic properties were studied. The results show that manganese zinc ferrite powders with different particle sizes from 10nm to 20nm can be obtained by adjusting pH value and reflux time. The optimum reflux time of complete product is 6h.pH value, which has great influence on the intensity of reaction and magnetic properties. When the pH value of coprecipitation is about 13.0, the size of the prepared nano-powder is about 20nm, and the saturation magnetization is 46A.m-2 / kg. In order to restrain the agglomeration of nanometer powder, the physical dispersion and chemical dispersion are combined, the agglomeration is solved by physical means, and then the dispersant is added to realize the stabilization of the particles, which can achieve a better dispersion effect. Nano-sized manganese zinc ferrite powders with good dispersion were obtained. The effect of the substitution of rare earth element La NdGd) on the structure and magnetic properties of spinel ferrite has also been studied. When rare earth ions replace Fe3 in spinel ferrite lattice, rare earth ions may enter spinel lattice or form compounds to enter grain boundary. It is found that the addition of rare earth ions can decrease the lattice constant and grain size of spinel ferrite due to the difference of effective magnetic distance and ionic radius between La _ 3 and ND _ 3 Gd _ 3), and increase its coercivity HC. The change of saturation magnetization is related to the addition of rare earth ions.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2010
【分類號(hào)】：TB383.1

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