Phase Transformations in ε-/γ'-Iron Nitride Compound Layers in the Temperature Range of 613 K - 693 K

2005 ◽  
Vol 237-240 ◽  
pp. 1147-1152 ◽  
Author(s):  
Tatiana Liapina ◽  
Andreas Leineweber ◽  
Eric J. Mittemeijer

ε/γ'-iron nitride (ε-Fe3N1+x, γ'-Fe4N) compound layers with thicknesses of about 10 µm were grown on pure α-Fe by gas nitriding at 823 K followed by quenching and were annealed at different temperatures in the range of 613 K – 693 K for different periods of time. These heat treatments led to a redistribution of nitrogen within the compound layer as well as between the compound layer and the adjacent ferrite, inducing thickness changes of the ε- and γ'-layers. The changes were analysed by light microscopy, electron probe microanalysis and X-ray diffraction. Models to describe and interpret the phase transformations in the ε/γ'-iron nitride compound layers as a function of time and temperature are discussed.

2014 ◽  
Vol 625 ◽  
pp. 651-656 ◽  
Author(s):  
Masashi Yoshida ◽  
Zhou Tao ◽  
Noah Utsumi

In this study, aluminum alloys were subjected to nitriding at 823 K for 0–18.0 ks using alumina and magnesium powders for improving their radiation performance. After nitriding, aluminum nitride films were formed on the aluminum substrate. The thickness of the formed films varied from 1.5 to 11 μm, and the color of the film surface was dark brown or black. The thickness of the aluminum nitride film increased with an increase in the treatment time. X-ray diffraction and electron probe microanalysis results showed that the film was composed of aluminum nitride, alumina, aluminum, and magnesium. Further, the film showed good adhesion at 0 ks.


2003 ◽  
Vol 18 (12) ◽  
pp. 2814-2819 ◽  
Author(s):  
Tetsuji Saito ◽  
Hironori Sato ◽  
Tetsuichi Motegi

The use of the glass slag method in the extraction of rare earth from La–Ni alloys was studied. X-ray diffraction and electron probe microanalysis studies revealed that the La–Ni alloys produced by the glass slag method using boron trioxide consisted of Ni and Ni3B phases. No La-containing phase such as the LaNi5 phase and the La oxide phase was found in the resultant alloys. The chemical analyses confirmed that the La content in the alloys produced by the glass slag method was very limited. However, the glass slag materials contained a large amount of lanthanum. The La in the La–Ni alloys was successfully extracted by the glass slag method using boron trioxide.


2007 ◽  
Vol 62 (11) ◽  
pp. 1383-1389 ◽  
Author(s):  
Barbara Schüpp-Niewaa ◽  
Larysa Shlyk ◽  
Yurii Prots ◽  
Gernot Krabbes ◽  
Rainer Niewa

Dark red single crystals of the new phases Ba3YRu0.73(2)Al1.27(2)O8 and Ba5Y2Ru1.52(2)Al1.47(2)O13.5 have been grown from powder mixtures of BaCO3, Y2O3, Al2O3, and RuO2 . The compositions given in the formulas result from the refinements of the crystal structures based on single crystal X-ray diffraction data (hexagonal P63/mmc (No. 194), Z = 2, Ba3 YRu0.73(2)Al1.27(2)O8: a = 5.871(1), c = 14.633(3) Å , R1 = 0.035, wR2 = 0.069 and Ba5Y2Ru1.52(2)Al1.47(2)O13.5: a = 5.907(1), c = 24.556(5) Å, R1 = 0.057, wR2 = 0.114). Ba3YRu0.73(2)Al1.27(2)O8 crystallizes in a 6H perovskite structure, Ba5Y2Ru1.52(2)Al1.47(2)O13.5 has been characterized as a 10H Perovskite. Due to similar spatial extensions of (Ru2O9) facesharing pairs of octahedra and (Al2O7) vertex-sharing pairs of tetrahedra, both structures show partial mutual substitution of these units. Consequently, the title compounds may be written as Ba3Y(Ru2O9)1−x(Al2O7)x, x = 0.64(1) and Ba5Y2RuO6(Ru2O9)1−x(Al2O7)x, x = 0.74(1). This interpretation is supported by the results of electron probe microanalysis using wavelength-dispersive X-ray spectroscopy. An oxidation state of Ru close to +5 for the (Ru2O9) units, as can be derived from the distances d(Ru-Ru), additionally leads to similar charges of both the (Ru2O9) and the (Al2O7) units.


1996 ◽  
Vol 11 (9) ◽  
pp. 2142-2151 ◽  
Author(s):  
Libin Liu ◽  
Zhanpeng Jin

The phases present around the (Bi, Pb)2Sr2Ca2Cu3Ox (2223) phase between 830–880 °C have been studied by x-ray diffraction (XRD) and electron probe microanalysis (EPMA) methods. The decomposition and melting temperatures of the 2223 phase in these samples have been measured by the differential thermal analysis (DTA) method. Partial substitution of Bi with Pb (Pb: Bi = 3: 22) does not change the 850 °C phase relations around 2223 phase. 2223 decomposes to liquid, Sr7Ca7Cu24O41 (7724), and Ca2CuO3 at 875 °C. The invariant reactions (degree of freedom is zero) among 2223, 7724, Ca2CuO3, CuO, Bi2Sr2CaCu2O8 (2212), and liquid were proposed to be L + 7724 + Ca2CuO3 → 2223 + 2212, L + 7724 + Ca2CuO3 → 2223 + CuO, L + 7724 → 2223 + 2212 + CuO. The reaction temperatures were estimated to be 860 °C, 860 °C, and 854 °C, respectively. An invariant reaction scheme and a tentative liquidus projection were sketched out.


2007 ◽  
Vol 1044 ◽  
Author(s):  
Veronique Da Ros ◽  
Juliusz Leszczynski ◽  
Bertrand Lenoir ◽  
Anne Dauscher ◽  
Christophe Candolfi ◽  
...  

AbstractThe preparation of partially filled n-type InxCo4Sb12 skutterudite compounds has been recently reported. The results were particularly promising, the materials exhibiting a ZT value far higher than one at moderated temperature. In this paper, we propose to investigate another way to tune the electrical and thermal properties by substituting Co atoms by Ni atoms in InxCo4Sb12. InxCo4-yNiySb12 polycrystalline samples have been prepared by a conventional metallurgical route. Structural analyses have been carried out by X-ray diffraction. The chemical composition and micro-homogeneity have been checked by electron probe microanalysis. Measurements of the electrical resistivity, thermoelectric power and thermal conductivity have been performed between 300 and 800 K. The influence of the presence of Ni on the thermoelectric properties of InxCo4Sb12 compounds is presented and discussed.


2013 ◽  
Vol 702 ◽  
pp. 145-148 ◽  
Author(s):  
Xiao Dong Liu ◽  
Jin Zhu Zhang ◽  
Si Si Zhu

The interaction among Lanthanum, Arsenic and Iron at 1223K were studied by means of electron probe microanalysis, optical microscopy and X-ray diffraction. The result shows that the gray phase might be a ternary compound La10Fe50As40, and the binary compound LaAs and the ternary compound La10Fe50As40 are the main interaction products when the atomic ratio of La to As is 1:3. The eutectic compound Fe2As can be precipitated from ferrite with the temperature decreasing.


2012 ◽  
Vol 482-484 ◽  
pp. 1281-1284
Author(s):  
Yuan Zhi Lin ◽  
Xiao Dong Liu ◽  
Jin Zhu Zhang

The interaction in the Cerium-Arsenic-Iron system at high temperature were studied by means of electron probe microanalysis, optical microscopy and X-ray diffraction. The results show that the CeAs is the main product when the atomic ratio of Cerium to Arsenic is 1:2, and a light gray phase in bright field might be a ternary compound Ce12Fe57.5As41. The diffusion coefficient of Arsenic in iron was calculated as 1.606×10-13m2/S.


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