本文選題：稀土金屬間化合物　切入點：磁熱效應(yīng)　出處：《河北工業(yè)大學(xué)》2014年博士論文　論文類型：學(xué)位論文

【摘要】：磁制冷技術(shù)因其綠色環(huán)保、高效節(jié)能等優(yōu)點而備受關(guān)注，具有廣泛的應(yīng)用前景。為促進磁制冷技術(shù)的廣泛應(yīng)用，探索具有優(yōu)秀磁熱性能的磁制冷材料具有重要的意義。本文研究了Fe3C型的Er3-xGdxCo、MgZn2型的Er1-xGdxCoAl、ZrNiAl型的(TmNi1-xCuxAl和HoNi1-xCuxIn)、ThCr2Si2型的RCu2X2(R=Er, Ho和X=Si, Ge)及CrB型的TmGa稀土金屬間化合物的磁性和磁熱效應(yīng)，得到的主要結(jié)果如下。 1. Er3-xGdxCo (x=0-3)化合物相變溫度隨著Gd的增加向高溫移動，-ΔSM基本上是減小的趨勢，但是RC并不是單調(diào)變化的，Er1.5Gd1.5Co化合物的RC最大。在磁場變化5T時RC達到629J/kg，因為Gd替代出現(xiàn)了兩個連續(xù)的相變，拓寬了半峰寬。 2. TmNi1-xCuxAl和HoNi1-xCuxIn的XRD數(shù)據(jù)精修結(jié)果表明，在HoNi1-xCuxIn中鍵長的不同引起了Cu具有選擇性的替代Ni，這種替代方式對材料的相變有重要的影響。在TmNi1-xCuxAl中不存在選擇性替代，但是晶格參數(shù)隨著Cu含量的變化在x=0.6和x=0.65之間出現(xiàn)了跳躍。隨著Ni被Cu替代，Tm的磁矩從平面逐漸向c軸轉(zhuǎn)動，這種變化引起了相變溫度及磁性的變化。 3.在TmNi1-xCuxAl (x=0-1)系列化合物中TmCuAl呈現(xiàn)出的磁熱效應(yīng)最大。當(dāng)磁場變化為5T時，得到最大-ΔSM為24.3J/kg K。當(dāng)磁場變化為1T和2T時，-ΔSM分別為12.2J/kg K和17.2J/kg K。另外，在磁場變化2T和5T時，最大-ΔTad分別為4.6K和9.4K。當(dāng)磁場變化為5T時，HoNi0.7Cu0.3In的最大-ΔSM為20.2J/kg K，RC為356.7J/kg。當(dāng)磁場變化為2T時，，HoNi0.9Cu0.1In的最大-ΔSM為12.5J/kg K，RC為132J/kg。當(dāng)HoNi0.9Cu0.1In和HoNi0.7Cu0.3In化合物以1:1比例均勻混合，在磁場變化0-2T時，最大-ΔSM為9.4J/kg K，而RC提高到147J/kg，這是因為兩相混合拓寬了制冷溫區(qū)。 4. RCu2Si2和RCu2Ge2(R=Ho, Er)都是反鐵磁材料，TN都在10K以下，HoCu2Si2和ErCu2Si2在TN以上均存在著自旋玻璃。ErCu2Si2呈現(xiàn)出大的磁熵變，當(dāng)磁場變化5T時ErCu2Si2最大的-ΔSM達到了22.8J/Kg K，RC為166.5J/kg。特別是當(dāng)磁場變化1T和2T時，最大-ΔSM分別為8.3J/kg K和15.8J/kg K。大的-ΔSM值主要來自于磁場誘導(dǎo)的AFM-FM變磁轉(zhuǎn)變。 5. TmGa具有兩個連續(xù)的磁相變，即PM-AFM和AFM-FM相變。在AFM區(qū)域存在場誘導(dǎo)的AFM-FM變磁轉(zhuǎn)變。TmGa具有大的磁熱效應(yīng)，當(dāng)磁場變化為1T和2T時，最大-ΔSM分別為12.9J/kg K和20.7J/kg K；RC分別為69J/kg和149J/kg。另外，在磁場變化為1T和2T時ΔTad分別為3.2K和5K。
[Abstract]:Magnetic refrigeration technology has attracted much attention because of its advantages of green environment protection, high efficiency and energy saving, and has wide application prospects. In order to promote the wide application of magnetic refrigeration technology, It is of great significance to explore magnetic refrigeration materials with excellent magnetocaloric properties. The magnetic and magnetocalorimetric effects of Er3-xGdxCoMgZn2, Er1-xGdxCoAlNiAl, TmNi1-xCuxIntroy and RCu2X2Si2 RCu2X2R, Ho) and CrB type TmGa rare earth intermetallic compounds have been studied in this paper. The main results are as follows. 1. The phase transition temperature of Er3-xGdxCo + XN 0-3) compounds shifted to high temperature with the increase of Gd. But RC is not the largest RC of Er1.5Gd1.5Co compound with monotonic variation. When the magnetic field changes 5T, RC reaches 629J / kg, because the Gd substitution has two consecutive phase transitions and widths the width of the half peak. 2. The refinement results of XRD data of TmNi1-xCuxAl and HoNi1-xCuxIn show that the difference of bond length in HoNi1-xCuxIn leads to the selective substitution of Ni in Cu, which has an important effect on the phase transition of the material. There is no selective substitution in TmNi1-xCuxAl. However, with the change of Cu content, the lattice parameters jump between x0. 6 and x0. 65. With the magnetic moment of Ni replaced by Cu gradually turning from plane to c axis, the change of phase transition temperature and magnetism is caused by the change of lattice parameters. 3. TmCuAl exhibits the largest magnetocaloric effect in the TmNi1-xCuxAl series. When the magnetic field changes to 5T, the maximum 螖 SM is 24.3J / kg K. when the magnetic field changes to 1T and 2T, the 螖 SM is 12.2J / kg / kg K and 17.2J / kg / kg K respectively. In addition, when the magnetic field changes 2T and 5T, The maximum 螖 Tad was 4.6K and 9.4K, respectively. When the magnetic field changed to 5T, the maximum value of HoNi0.7Cu0.3In was 20.2J / kg KN RC = 356.7J / kg. When the magnetic field changed to 2T, the maximum value of HoNi0.9Cu0.1In was 12.5J / kg KRC = 132J / kg.When HoNi0.9Cu0.1In and HoNi0.7Cu0.3In compounds were mixed uniformly at 1: 1, when the magnetic field changed 0-2T, The maximum-螖 SM is 9.4 J / kg Kand while RC increases to 147 J / kg, which is because the two-phase mixing widens the refrigeration temperature range. 4. Both RCu2Si2 and RCu2Ge2Ge RU Ho, er) are antiferromagnetic materials. There exists a large magnetic entropy change in spin glass, ErCu2Si2 and ErCu2Si2 both below 10K. When the magnetic field changes 5T, the maximum -螖 SM of ErCu2Si2 reaches 22.8JKg / KG RC = 166.5J / kg. especially when the magnetic field changes 1T and 2T, respectively. The maximum-螖 SM is 8.3J / kg K and 15.8J / kg K, respectively. 5. TmGa has two continuous magnetic transitions, namely, PM-AFM and AFM-FM. There is a great magnetocaloric effect on the field-induced AFM-FM magnetoconversion in the AFM region. When the magnetic field changes to 1T and 2T, the maximum 螖 SM is 12.9J / kg K and 20.7 J / kg KNRC are 69J / kg and 149J / kg, respectively. In addition, when the magnetic field changes to 1T and 2T, the maximum 螖 SM is 12.9 J / kg K and 20.7 J / kg KNRC are 69 J / kg and 149 J / KG, respectively. When the magnetic field changes to 1T and 2T, 螖 Tad is 3.2k and 5Krespectively.
【學(xué)位授予單位】：河北工業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TB64

【參考文獻】

相關(guān)期刊論文 前1條

1 陳遠富,陳云貴,滕保華,唐永柏,付浩,唐定驤,涂銘旌;磁制冷發(fā)展現(xiàn)狀及趨勢:Ⅱ磁制冷技術(shù)[J];低溫工程;2001年02期

本文編號：1633195