Ling Min Zeng

Thermal Expansion, Magnetic and Electrical Properties of Ternary Compound DyCo0.67Ga1.33

The ternary compound DyCo0.67Ga1.33 was synthesized and the thermal expansion of DyCo0.67Ga1.33 was studied in the temperature range of 309–608 K by high temperature powder X-ray diffraction technique. The volumetric coefficient of thermal expansion, , can be represented by . Its magnetic properties were measured between 30 and 300 K, and the magnetic susceptibility of DyCo0.67Ga1.33 was found to follow the Curie–Weiss law in the temperature range of 40–300 K. The effective magnetic moment and paramagnetic Curie temperature were estimated to be 9.86 μB and 40.4 K, respectively. Electrical resistivity of the compound DyCo0.67Ga1.33 was also measured between 5 and 300 K. Temperature variation of the electrical resistivity suggests the metallic character of the compound DyCo0.67Ga1.33 with an anomaly detected at 45 K. The residual resistivity ratio RRR of the compound is about 1.2.

X-Ray Powder Diffraction Data and Crystal Refinement of a New Compound AlCrNi3Pr

Rare earth-transition metal (R-T) intermetallics have been well used because of their excellent properties. The X-ray diffraction patterns of many new phases in the R-T system have not been extensively studied. A new compound AlCrNi3Pr was prepared by arc melting using non-consumable tungsten electrode under argon atmosphere, and then annealed at 1023K for 30 days. The X-ray powder diffraction data of AlCrNi3Pr was collected on a Rigaku SmartLab X-ray powder diffractometer. The powder patterns of the compound were indexed, and the structure refinement by using Rietveld method indicated that the AlCrNi3Pr compound crystallized in the hexagonal structure, space group P6/mmm (No.191) with PrNi5 structure type, a=b=5.0553(9) Ǻ, c=4.0763(6) Ǻ, V=90.22Ǻ3, Z=1, ρx=7.288g cm-3, the Smith–Snyder FOM F30=279.1(0.0044, 32) and the intensity ratio RIR=1.23.

Crystal Structure of Al2Cu3Nd Ternary Compound

A new Al-Cu-Nd system alloy, the high-purity Al2Cu3Nd ternary compound, was developed and prepared with the stoichiometric amounts of elemental constituents by arc melting under argon atmosphere. The X-ray diffraction (XRD) data of Al2Cu3Nd was collected by using the Rigaku Smart Lab X-ray powder diffractometer, and all X-ray diffraction peaks of Al2Cu3Nd compound were indexed successfully with the hexagonal structure. The Rietveld refinement results of the XRD pattern for the Al2Cu3Nd compound showed that the Al2Cu3Nd compound is the hexagonal structure, space group P6/mmm (No.191) with a = 5.2397(1) Å, c = 4.1783(1) Å, V = 99.34 Å3, Z = 1. The density of the compound was 6.501 g/cm3, and its reference intensity ratio (RIR) w 1.26.

Investigation on the Thermal Stability of the Compounds Y1-xErxCo5 (x = 0, 0.12, 0.24)

The rare earth-cobalt compounds with CaCu5-type structure were discovered to have outstanding permanent magnetic properties. The thermal stability of Y1-xErxCo5 (x = 0, 0.12, 0.24) was investigated by X-ray powder diffraction, differential thermal analysis and scanning electron microscopy with energy dispersive analysis. The influence of Er for Y on the decomposition of Y1-xErxCo5 was discussed. The substitution of Er for Y in the compound YCo5 obviously enhanced the decomposition temperature and accelerated the decomposition reaction of the compounds Y1-xErxCo5 into (Y1-xErx)2Co17 and (Y1-xErx)2Co7.

Phase Equilibria in the Er-Cu-V and Dy-Cu-V at 773K

The isothermal sections of the Er-Cu-V and Dy-Cu-V ternary systems at 773K were investigated by experiments. The isothermal section of Er-Cu-V consists of 8 single-phase regions, 13 two-phase regions and 6 three-phase regions. The binary compounds ErCu5, ErCu2, ErCu, Er2Cu9 and Er2Cu7 were observed at 773K. The isothermal section of Dy-Cu-V consists of 7 single-phase regions, 11 two-phase regions and 5 three-phase regions. The binary compounds DyCu5, DyCu2, DyCu and Dy2Cu9 were confirmed at 773K. No ternary compound was found in the two sections. There is no solubility of V in the Er-Cu and Dy-Cu binary compounds observed.

Investigation on the Thermal Stability of the Compounds Y3Fe29-xCrx

Binary compound Y3Fe29 cannot be directly formed by rare earth Y and Fe and the third element M (non-iron transition elements) must be introduced to form ternary compound Y3(Fe,M)29. In this work, six alloys with compositions of the Y3Fe29-xCrx (x=1,2,3,4,5,6) were prepared and investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and differential thermal analysis (DTA). The study on the thermal stability of these compounds points to that the compoundY3(Fe,Cr)29 is a high temperature phase and exists above 1100K. The alloys with single-phase of Y3(Fe,Cr)29 was decomposed into Y2(Fe,Cr)17 and Y(Fe,Cr)12 annealed at high temperature 1100K.