本文選題：FePt + 磁性納米顆粒�。� 參考：《沈陽(yáng)師范大學(xué)》2015年碩士論文

【摘要】：社會(huì)的發(fā)展需要磁性材料向高性能,多功能方向發(fā)展,而納米磁性材料能夠有更好的磁性能及塊體納米磁性材料所沒(méi)有的其他功能。面心立方(FCT)相FePt具有高的磁晶各向異性,超順磁臨界尺寸為2-4nm,化學(xué)穩(wěn)定性好,因而能夠作為很好的納米磁性材料�，F(xiàn)今制備FePt納米材料主要分兩大類：物理方法制備FePt納米薄膜和化學(xué)合成FePt納米顆粒。但是制備面心四方(FCT) FePt納米材料的最大問(wèn)題是材料進(jìn)行退火熱處理過(guò)程中會(huì)發(fā)生團(tuán)聚和燒結(jié)現(xiàn)象。為此,物理制備方法制備納米FePt時(shí)主要有兩種策略,一種是通過(guò)降低退火溫度,如通過(guò)摻雜Ag, Cu, Au等,另一種是減少退火時(shí)間,如快速退火,激光退火等。另外FePt納米薄膜可以在強(qiáng)磁場(chǎng)和合適的基底取向生長(zhǎng)。但是物理方法制備出的FePt有序度不高,小于0.7.而化學(xué)合成FePt納米顆粒的主要方法有兩種,一種是化學(xué)合成面心四方(FCC)相納米顆粒再鹽浴退火,另一種是在FCC-FePt納米顆粒外包覆一層高熔點(diǎn)物質(zhì)來(lái)阻止退火時(shí)的燒結(jié)和團(tuán)聚,如MgO, SiO2等�；瘜W(xué)合成制備FCT FePt的優(yōu)點(diǎn)是顆粒的大小,形狀都是能夠很好的控制的,有序度高,可大于0.8。但化學(xué)制備FCT-FePt步驟稍多。本文針對(duì)化學(xué)合成法制備FePt納米顆粒的實(shí)驗(yàn)步驟多,合成出的納米顆粒還需要高溫退火會(huì)導(dǎo)致顆粒團(tuán)聚現(xiàn)象,采用一步固相燒結(jié)法直接制備FCT相FePt納米顆粒：直接用乙酰丙酮鐵和乙酰丙酮鉑與氯化鈉(或氯化鉀)球磨混合均勻,然后直接高溫煅燒制備FCT的FePt納米顆粒。通過(guò)對(duì)此方法制備出的FePt納米顆粒進(jìn)行VSM、XRD、TEM等手段進(jìn)行磁性能、晶體結(jié)構(gòu)、微觀形貌與結(jié)構(gòu)等表征分析。論文的主要研究?jī)?nèi)容和結(jié)果如下：1.通過(guò)調(diào)節(jié)Fe、Pt前驅(qū)體的摩爾量,當(dāng)Fe、Pt元素在1：3和3：1時(shí),制備出的納米顆粒的矯頑力很低,XRD分析表征制備出的分別是FePt3和Fe3Pt;發(fā)現(xiàn)Fe、Pt比例在1：1時(shí)制備出的FePt納米顆粒有較好的磁性能,制備出的顆粒是FCT結(jié)構(gòu)。2.固定Fe、Pt前驅(qū)體比例為1：1,通過(guò)調(diào)節(jié)NaCl的量,對(duì)比在不同比例的NaCl與Fe、Pt前驅(qū)體混合后制備出的FePt納米顆粒的磁性能和微觀形貌與結(jié)構(gòu)分析,表明當(dāng)NaCl與Fe、Pt前驅(qū)體的比例在不超過(guò)2000：1時(shí),可以制備出FCT結(jié)構(gòu)的FePt納米顆粒,且隨著氯化鈉比例的降低,顆粒平均尺寸逐漸增加,矯頑力逐漸增加,當(dāng)氯化鈉與FePt的摩爾比在300：1時(shí),矯頑力達(dá)到22KOe。3.通過(guò)對(duì)比不同溫度下煅燒時(shí)制備出的顆粒磁性能,煅燒溫度在750℃時(shí),磁性能最高,隨著煅燒溫度的降低,矯頑力也逐漸降低,顆粒平均尺寸也有所降低,并且在低于400℃煅燒時(shí)仍制備出FCT相的FePt納米顆粒,其矯頑力在5K0e。本論文中的一步固相法燒結(jié)制備FePt納米顆粒,操作步驟少,不需要先化學(xué)合成FCC相FePt納米顆粒,能夠直接制備出FCT相FePt納米顆粒；與核殼結(jié)構(gòu)相比(SiO2,MgO外層保護(hù))用鹽可以有效阻止FePt燒結(jié)時(shí)的晶粒過(guò)分長(zhǎng)大,不會(huì)降低FePt的性能或去除保護(hù)層時(shí)會(huì)破壞FePt的完整性。
[Abstract]:The development of the society requires magnetic materials to be high and multi-functional, and nano magnetic materials can have better magnetic properties and other functions. The FCT phase FePt has high magnetocrystalline anisotropy, the superparamagnetic critical size is 2-4nm, and the chemical stability is good, so it can be used as a good one. FePt nanomaterials are mainly divided into two major categories: the preparation of FePt nanomaterials by physical methods and the chemical synthesis of FePt nanoparticles. But the biggest problem of preparing the FCT FePt nanomaterials is the agglomeration and sintering of the materials during the annealing process. There are two main strategies for m FePt. One is by reducing the annealing temperature, such as by doping Ag, Cu, Au and so on. The other is to reduce the annealing time, such as fast annealing, laser annealing, etc., and the FePt nanomilt can grow in strong magnetic field and suitable substrate orientation. But the FePt order of the physical method is not high, less than 0.7. and chemistry. There are two main methods for the synthesis of FePt nanoparticles, one is the chemical synthesis of FCC phase nano particles in the salt bath annealing, the other is that the FCC-FePt nanoparticles are coated with a high melting point material to prevent the sintering and agglomeration, such as MgO, SiO2, etc.. The advantage of the chemical synthesis of FCT FePt is the size and shape of the particles. It is able to be well controlled, with high order degree, more than 0.8., but more than 0.8., but there are more steps in preparing FCT-FePt. In this paper, there are many experimental steps to prepare FePt nanoparticles by chemical synthesis, and the synthesized nanoparticles also need high temperature annealing to lead to the agglomeration of particles. A one-step solid phase sintering method is used to direct the preparation of FCT phase FePt nanoparticles directly. FCT FePt nanoparticles were prepared by ball milling of acetacetone iron and acetacetone (or acetylacetone) with sodium chloride (or potassium chloride). The magnetic properties, crystal structure, micromorphology and structure of the FePt nanoparticles prepared by this method were analyzed by means of VSM, XRD, TEM and other means. The results are as follows: 1. by adjusting the molar amount of Fe, Pt precursor, when Fe and Pt are in 1:3 and 3:1, the coercive force of the prepared nanoparticles is very low, and FePt3 and Fe3Pt are prepared by XRD analysis, and Fe and Pt ratio are found to have good magnetic properties. The ratio of Fe and Pt precursor is 1:1. By adjusting the amount of NaCl, the magnetic properties and microstructure and microstructure of FePt nanoparticles prepared by NaCl and Fe, Pt precursor are compared. The results show that when the proportion of NaCl and Fe and Pt precursor is not more than 2000:1, the nanoparticles can be prepared. With the reduction of sodium chloride ratio, the average size of the particles increases gradually and the coercivity increases gradually. When the molar ratio of sodium chloride to FePt is at 300:1, the coercive force reaches 22KOe.3. by comparing the magnetic properties of the particles prepared at different temperatures. The magnetic energy is highest when the calcining temperature is 750, and the coercive force is also driven by the calcining temperature. The average size of the particles is also reduced, and the FePt nanoparticles of FCT phase are still prepared at less than 400 C. The coercive force is prepared by one step solid phase sintering in the 5K0e. paper. The operation steps are less, and the FCC phase FePt nanometers are not needed to be synthesized first, and the FCT phase FePt nanoparticles can be prepared directly. Compared with the core shell structure (SiO2, MgO outer protection), the salt can effectively prevent the grain from excessive growth when FePt is sintered, which will not reduce the performance of FePt or destroy the integrity of the FePt when the protection layer is removed.
【學(xué)位授予單位】：沈陽(yáng)師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.1

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本文編號(hào)：1954993