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1.
本文研究了轻稀土负磁致伸缩SmFe_x(1.40<x<1.94),Sm_xDy_(1-x)Fe_y(0.84<x<0.92.1.80<y<1.90),Sm_(0.90)Dy_(0.10)(Fe_(0.95)Al_(0.05))_(1.80)晶体的制备、热处理及磁学性能,发现SmFe_x合金的λ-x曲线存在两个峰值,峰值的x点随热处理发生的变化有一定的规律性,还比较了热处理前后,Sm-Fe、Sm-Dy-Fe和Sm-Dy-Fe-Al的相组成对性能的影响。热处理用于改善磁致伸缩性能,并且制得了高磁致伸缩性能的SmFe_2和(Sm,Dy)Fe_2合金。  相似文献   

2.
超负磁致伸缩晶体Sm—Fe,Sm—Dy—Fe和Sm—Dy—Fe—Al的研究   总被引:1,自引:0,他引:1  
本文研究了轻稀土负磁致伸缩SmFex(1.40≤x≤1.94),SmxDy1-xFey(0.84≤x≤0.92,1.80≤y≤1.90),Sm0.90Dy0.10(Fe0.95Al0.05)1.80晶体的制备,热处理及磁学性能,发现SmFex合金的λ-x曲线存在两个峰值,峰值的x点热处理发生的变化有一定的规律性,还比较了热处理前后,Sm-Fe、Sm-Dy-Fe和Sm-Dy-Fe-Al的相组成对性能  相似文献   

3.
蒋成保  宫志凯 《功能材料》1997,28(6):570-572
研究了经超高温梯度向凝固制备的Tb0.3Dy0.7(Fe,M)1.95合金样品中存在的晶体缺陷的类型,分析其对该材料磁致伸缩性能的影响,探讨如何调整工艺来消除晶体缺陷,提高材料的磁致伸缩性能。  相似文献   

4.
贮氢合金Zr(Mn1—xNix)2的相结构   总被引:2,自引:1,他引:1  
贮氢合金Zr(Mn1-xNix)2(0.40≤x≤0.75)的多相Rietveld分析表明,它是以C15型Laves相ZrM2为主的多相体系。不同M/Zr原子比(M=Nix或Mn1-x)非Laves相合金的出现与丰度和整个合金成分配比中Ni/Zr原子比的变化一致,并与Ni-Zr相图中具有同样Ni/Zr原子比的金属间化合物有相同的晶型。x=0.75,Zr7M10的丰度是38.57%;x=0.55,C  相似文献   

5.
TbDyFe合金的组织和磁致伸缩性能   总被引:6,自引:0,他引:6  
定向凝固TbDyFe合金具有(112)择优取向,热处理能明显地改变显微镜组织和磁致伸缩性能,在1100℃真空处理2h后,磁致伸缩性能最好,空冷和炉冷对磁致伸缩性能影响不大,富稀土相的球化和晶粒吞并长大,减小了磁化过程中90°磁畴转动的阻力,是高温处理提高磁致伸缩性能的根本原因。  相似文献   

6.
稀土超磁致伸缩材料取向生长和控制   总被引:1,自引:1,他引:0  
分析了稀土超磁致伸缩材料RFe2(R=Tb Dy)合金然凝固时晶体择优取向、取向度与磁致伸缩性能之间的关系;对一定成分的RFe2合金,凝固条件(GTL和R)是影响晶体择优取向和取向度的决定性因素;比较了目前常用的研究和制备RFe2合金方法的优缺点,提出ZMLMC法是控制和提高RFe2合金凝固时晶体取向和取向度的理想方法。  相似文献   

7.
本文对用于制造高效率半导体发光器件的材料──Ga_(1-x)Al_xAs(x=0.75)外延层沿生长方向上铝组分的分布进行了详细地讨论。采用电液相外延法能获得铝组分高度稳定的Ga_(1-x)Al_xAs外延层,并用电流诱导效应作了初步理论解释。  相似文献   

8.
研究了用溶胶-凝胶(sol-gel)方法在LaAlO3(100)衬底上制备的La-1xCaxMn1.03O3外延薄膜的磁电阻效应。x在0.2~0.621范围内变化,外延薄膜的电阻率与温度的关系从类半导体行为向金属导电行为转变。在x≥0.5的4个样品中没有发现电荷有序绝缘体(COI)和反铁磁绝缘体(AFI)现象。x=0.2样品在1.5T磁场下磁电阻率MR的最大值为10^4%、磁转变温度为230K。  相似文献   

9.
本文研究了Fe76.5-xCu1NbxSi13.5B9纳米晶合金中Nb含量的变化(x=1-7)对结构和磁性的影响。结果表明,随x值的增高,α-Fe(Si)纳米晶相的尺寸减小,体积分数,含Si量及其DO3有序度降低。Nb含量对残余非晶相的结构有影响。合金的饱和磁致伸缩系数(λs)随x值的增加而增大,在x=3时,合金的起始磁导率(μi)最大,矫顽力(Hc)最小。  相似文献   

10.
本文研究了Fe(76.5-x)Cu1NbxSi(13.5)B9纳米晶合金中Nb含量的变化(x=1-7)对结构和磁性的影响。结果表明,随x值的增高,α-Fe(Si)纳米晶相的尺寸减小,体积分数,含Si量及其DO_3有序度降低。Nb含量对残余非晶相的结构有影响。合金的饱和磁致伸缩系数(λs)随x值的增加而增大,在x=3时,合金的起始磁导率(μi)最大,矫顽力(Hc)最小。  相似文献   

11.
针对两种新型稀土型储氢合金La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2的储氢特性进行研究分析。实验表明,相同温度下,La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2合金的PCT曲线基本重合,且都具有优良的吸氢动力学性能;相比之下,后者的滞后系数要小于前者,吸氢量较大,吸氢速率也较快,故其储氢性能较优。300次吸放氢循环实验结果表明,La0.5Y0.5Ni4.8Al0.2合金的吸氢动力学性能虽然略有下降,但抗粉化性能较好。  相似文献   

12.
The thermal stability of amorphous ternary hydrides Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45) and their corre-sponding amorphous binary alloys Mg_(50)Ni_(50) and Mg_(30)Ni_(70) were studied with X-ray diffraction(XRD) and differential scanning calorimetry(DSC). Samples of the amorphous alloys were preparedby mechanical alloying and the amorphous hydrides were obtained by charging the alloys with gas-eous hydrogen at 3.0 MPa and 423 K. It was found that the amorphous hydrides released most oftheir hydrogen before the crystallization of the essentially hydrogen depleted amorphous alloy. Thecrystallization temperature of amorphous Mg_(50)Ni_(50)H_(54) elevated and that of amorphousMg_(30)Ni_(70)H_(45) did not change in relation to the original binary amorphous alloy. This is very excep-tional for amorphous hydrides. The reason for the effects of hydrogen absorption/desorption on thecrystallization of amorphous alloys was discussed.  相似文献   

13.
根据Zr65Al7。5Ni10Cu15Co2。5合金的纳米晶,晶体,液体和玻璃比热的测量结果,研究了合金的玻璃转变温度与全金的热力学函数,动力学参数以及加热速度的关系。结果表明,非晶态合金玻璃转变所需转变激活能很小,玻璃转变温度实际上是由于加热速度引起的不同状态的玻璃与液体的热力学平衡温度。  相似文献   

14.
Experimental studies and analysis of acousto-optic diffraction in alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are given. Ultrasonic wave velocity, elastic compliance and stiffness coefficients, and piezo-optic and photoelastic coefficients of alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are determined. The acousto-optic figure of merit has been estimated for different possible geometries of acousto-optic interaction. It is shown that the acousto-optic figures of merit for alpha-BaB(2)O(4) crystals reach the value M(2)=(270 +/- 70) x 10(-15) s(3)/kg for the case of interaction with the slowest ultrasonic wave. The directions of propagation and polarization of those acoustic waves are obtained on the basis of construction of acoustic slowness surfaces. The acousto-optic diffraction is experimentally studied for alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals.  相似文献   

15.
Tao X  Wang X  Li X 《Nano letters》2007,7(10):3172-3176
Two kinds of aluminum borate nanowires, Al(4)B(2)O(9) and Al(18)B(4)O(33), were successfully synthesized by a one-step combustion method through control of the Al:B atomic ratio and synthesis temperature. Both nanowires are single crystalline but have distinguishing growth habits. Nanoindentation tests were performed directly on individual nanowires to reveal their mechanical properties. A 70% reduction in elastic modulus was found in Al(18)B(4)O(33) nanowires compared with their bulk counterpart. Al(18)B(4)O(33) nanowires exhibited higher hardness and elastic modulus than Al(4)B(2)O(9) nanowires.  相似文献   

16.
The natural passive films forrned on Fe_(40)Ni_(40)P_(14)B_6 and Fe_(54.6)Ni_(38)Si_(4.1)B_(2.3)V_1 amorphous alloys long-term exposed in air have been studied by X-ray photoelectron spectroscopy (XPS) and Auger electron (including Ar+ ion depth profiling) spectroscopy (AES). The following aspects have been investigated: (1) chemical states of the elements in the films. binding energies and the chemical shifts measured by XPSf (2) structure and composition of the films fand (3) thickness of the passive films determined by AES depth profiling and XPS analysis.  相似文献   

17.
18.
The surfaces of poly(l-lactic acid) (PLLA) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) were modified by oxygen and nitrogen plasma treatments. The physical and chemical surface characteristics were evaluated by contact angle tests, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The plasma treatments caused an increase in both contact angle and roughening, altered the surface morphology, inserted polar groups, and, consequently, enhanced the hydrophilicity for both PLLA and PHBV polymers.  相似文献   

19.
Phase decomposition in amorphous Cu12.5Ni10Zr411Ti14Be22.5 alloy as annealed in the super-cooled liquid range was studied by applying small angle neutron scattering (SANS). As annealed between 600 K and 700 K, the alloy was observed to decompose into two new amorphous phases,with the second phase precipitates embedded in the matrix of the first. Long time annealing of the alloy results in crystallization in addition to evolution of the decomposed microstructure.The kinetic diagram of the decomposition and crystallization for this alloy is given. The second phase precipitates have several nanometers in size and occupy a quite low volume fraction. The decomposition of the supercooled liquid in overall temperature range exhibits the features of spinodal reaction.  相似文献   

20.
The work functions before and aftercrystallization of two glassy alloys,Pd_(83.5)Si_(16.5) andCu_(70)Ti_(30) have been measured by means of the con-tact potential difference method in the secondaryelectron field at room temperature under 10~(-5) Pavacuum.The results show that the work functionsof both glassy alloys are higher than those of thecorresponding crystalline alloys.  相似文献   

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