本文選題：磁制冷 + 馬氏體相變��； 參考：《上海電力學(xué)院》2017年碩士論文

【摘要】：磁制冷是一種利用磁性材料的磁熱效應(yīng)來實(shí)現(xiàn)制冷的新技術(shù),與傳統(tǒng)壓縮制冷相比,磁制冷技術(shù)具備環(huán)保、節(jié)能、靜音的顯著優(yōu)勢,有望取代傳統(tǒng)壓縮制冷技術(shù)。目前磁制冷技術(shù)已應(yīng)用于低溫制冷,但室溫磁制冷技術(shù)才剛起步,并且面臨很多難題,如誘導(dǎo)相變發(fā)生的磁場過大、磁性材料相變過程中磁滯熱滯較大、相變可調(diào)溫區(qū)較小等。Ni Mn基哈斯勒合金是一種新型的磁制冷材料,合金在降溫過程中,經(jīng)歷了一個從高溫奧氏體想到低溫馬氏體相的相變,并伴隨著磁化強(qiáng)度的突變,該相變屬于一級相變,研究表明磁化強(qiáng)度的突變可產(chǎn)生一個較大的磁熵變,實(shí)現(xiàn)巨磁熱相應(yīng)。在磁制冷技術(shù)中,起關(guān)鍵作用的是磁熵,磁性材料的磁熵變化時,伴隨著吸熱放熱的現(xiàn)象以達(dá)到制冷效果,但晶格熵和電子熵的存在降低了制冷效率。本文通過利用真空電弧爐制備合金樣品Nn50-xCoxMn36Sn14和Ni_(50-x)Co_xMn_(36)In_(14),探討了Co元素替代Ni位對合金的結(jié)構(gòu)、磁和磁熱性能的研究。并比較了不同的替代原子含量對合金的影響,具體如下:第一、二章分別介紹了磁制冷的原理、磁制冷工質(zhì)熵以及室溫磁制冷材料的發(fā)展現(xiàn)狀、制備方法和材料性能表征的技術(shù)手段。第三章研究了Nn50-xCoxMn36Sn14(x=0,0.5,1.5,2,3)合金,發(fā)現(xiàn)合金中有溫度、磁場誘導(dǎo)的反馬氏體相變,并且適量摻雜Co元素可以降低馬氏體相變溫度,提高居里溫度。磁熱效應(yīng)研究表明合金在馬氏體相變點(diǎn)附近具有較大的磁熵變,所以合金具有可觀的制冷量。另外發(fā)現(xiàn)合金的相變溫度可伴隨Co的摻雜進(jìn)行調(diào)節(jié)。通過對樣品磁熱效應(yīng)的計算,Ni49.5Co0.5Mn36Sn14的磁熵變達(dá)到了18.8 J/(kg K),并且在Ni48.5Co1.5Mn36Sn14中得到了較大的半峰寬,取得了較大的制冷量,最大達(dá)到了290.4 J/Kg。第四章主要對元素Co摻雜Ni對Ni_(50-x)Co_xMn_(36)In_(14)(x=2,3,4,5)合金的晶體結(jié)構(gòu)磁相變過程進(jìn)行分析和研究,結(jié)果表明隨著Co原子的增加,合金的馬氏體相變劇烈程度先增強(qiáng)后消失,同時發(fā)現(xiàn)合金的磁化強(qiáng)度顯著提高。以熱力學(xué)理論為基礎(chǔ),計算了合金的等溫磁熵變。最大達(dá)到了22.7J/(kg K)。第五章研究了Ni_(50-x)Co_xMn_(38)Al_(12)(x=4,6,8)合金,在合金中實(shí)現(xiàn)了從鐵磁的奧氏體到弱磁的馬氏體的馬氏體相變,并且得到了磁場誘導(dǎo)的變磁性行為。并且在反馬氏體相變得到了較大的磁化強(qiáng)度和磁熵變的變化。通過對樣品磁熱效應(yīng)的計算,我們在樣品Ni44Co6Mn38Al12中得到了較大的磁熵變,達(dá)到了22.3J/(kg K)。第六章對上述內(nèi)容進(jìn)行了總結(jié)并對目前Ni-Mn基哈斯勒合金的研究前景進(jìn)行了展望。提出可以在減小熱滯和磁滯、提高半峰寬等方面進(jìn)行改進(jìn),提高合金的磁熱效應(yīng)。
[Abstract]:Magnetic refrigeration is a new technology which uses magnetocaloric effect of magnetic material to realize refrigeration. Compared with traditional compression refrigeration, magnetic refrigeration technology has the advantages of environmental protection, energy saving and mute, which is expected to replace the traditional compression refrigeration technology. At present, magnetic refrigeration technology has been applied to low temperature refrigeration, but the room temperature magnetic refrigeration technology has just started, and it faces many difficulties, such as too large magnetic field induced phase transition, large hysteresis and thermal hysteresis in the process of magnetic material transformation. NiMn-based Hassler alloy is a new type of magnetic refrigeration material. During the cooling process, the phase transformation from high temperature austenite to low temperature martensite phase change, accompanied by a sudden change in magnetization. This phase transition belongs to the first order phase transition. It is shown that the sudden change of magnetization intensity can produce a large magnetic entropy change and realize the corresponding giant magnetocaloric change. In the magnetic refrigeration technology, the key role is the magnetic entropy. When the magnetic entropy changes, it is accompanied by endothermic and exothermic phenomena to achieve the refrigeration effect. However, the existence of lattice entropy and electron entropy reduces the refrigeration efficiency. In this paper, the structure, magnetic and magnetocalorimetric properties of the alloy prepared by vacuum arc furnace (VEAF) were investigated by preparing the alloy Nn50-xCoxMn36Sn14 and NiS / NiS / 50 / x / C\ +\ +\ {50\}\%\ The effects of different content of substitution atoms on the alloy are compared as follows: first, chapter two introduces the principle of magnetic refrigeration, the entropy of magnetic refrigerant and the development of magnetic refrigeration materials at room temperature. Preparation methods and technical means for characterization of material properties. In chapter 3, the alloy Nn50-xCoxMn36Sn14Sn14N14xP0. 5 / 1. 5 / 2) is studied. It is found that there is temperature and magnetic field induced anti martensite transformation in Nn50-xCoxMn36-Sn14. The appropriate amount of Co doping can decrease the temperature of martensite transformation and increase the Curie temperature of Nn50-xCoxMn36-Sn14. The study of magnetocaloric effect shows that the alloy has a large magnetic entropy change near the martensitic transformation point, so the alloy has considerable refrigerating capacity. In addition, it is found that the phase transition temperature of the alloy can be adjusted with Co doping. The magnetocaloric effect of Ni49.5Co0.5Mn36Sn14 has been calculated, and the magnetic entropy of Ni49.5 Co0.5Mn36Sn14 has reached 18.8 J/(kg KN, and the larger half peak width has been obtained in Ni48.5Co1.5Mn36Sn14, with a large refrigerating capacity of 290.4 J / Kg. In the fourth chapter, the magnetic transformation process of crystal structure of Ni + Co doped Ni _ 2O _ (50) -x _ (+) _ _ _ At the same time, it was found that the magnetization of the alloy increased significantly. The isothermal magnetic entropy change of the alloy was calculated on the basis of thermodynamics theory. The maximum reached 22.7J/(kg Ke. In the fifth chapter, we study the NiSZ 50-xX CoxMnM) alloy. The magnetic-induced martensite transformation from ferromagnetic austenite to weak magnetic field has been realized in the alloy. The magnetic field induced magnetization behavior has been obtained in the alloy. The results are as follows: (1) in the fifth chapter, we have studied the Nitix 50-x CoxMnM) alloy, and we have obtained the magnetic-induced transformation from ferromagnetic austenite to weak magnetic field. The changes of magnetization and magnetic entropy are also obtained in the anti-martensite transformation. Through the calculation of the magnetocaloric effect of the sample, we have obtained a large magnetic entropy change in the sample Ni44Co6Mn38Al12, which has reached the 22.3J/(kg Ke. In chapter 6, the above contents are summarized and the research prospect of Ni-Mn Kihassler alloy is prospected. It is suggested that the magnetocaloric effect of the alloy can be improved by reducing the thermal hysteresis and magnetic hysteresis and increasing the half peak width.
【學(xué)位授予單位】：上海電力學(xué)院
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TB64

【參考文獻(xiàn)】

相關(guān)期刊論文 前6條

1 Guang-Hua Yu;Yun-Li Xu;Zhu-Hong Liu;Hong-Mei Qiu;Ze-Ya Zhu;Xiang-Ping Huang;Li-Qing Pan;;Recent progress in Heusler-type magnetic shape memory alloys[J];Rare Metals;2015年08期

2 司曉東;劉永生;徐娟;杜文龍;雷偉;郭保智;高nI;彭麟;周桃;;室溫磁制冷材料研究進(jìn)展[J];磁性材料及器件;2015年04期

3 孔繁清;郭詠梅;;包頭稀土研究院磁制冷機(jī)研發(fā)取得突破[J];稀土信息;2015年01期

4 徐莉莎;王瑞龍;楊昌平;吳美玲;闞芝蘭;;Mn_(50)Ni_(39)Sn_(11-x)Al_x合金的磁相變及磁卡效應(yīng)[J];中國科學(xué):物理學(xué) 力學(xué) 天文學(xué);2012年07期

5 鐘喜春,曾德長,劉正義,魏興釗;室溫磁致冷材料及技術(shù)的研究進(jìn)展[J];材料科學(xué)與工程學(xué)報;2003年02期

6 李卓棠，吳佩芳;稀土材料的磁熱效應(yīng)及其應(yīng)用[J];化學(xué)進(jìn)展;1995年02期

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