Research on the Structure of GdFeMn Compound

2017 ◽  
Vol 1142 ◽  
pp. 14-18 ◽  
Author(s):  
Shi Qian Zhao ◽  
Lei Ma ◽  
Liang Zhou ◽  
Tao Liu ◽  
Yong Bin Guo

The crystal structure of GdFeMn alloy has been investigated by using X-ray powder diffraction (XRD) followed by Rietveld refinement technique, differential thermal analysis (DTA) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) techniques. XRD results showed that annealed GdFeMn alloy was a single phase of Gd6(Fe0.5Mn0.5)23 compound, with Th6Mn23-structure. SEM/EDS results and Rietveld refinement revealed that GdFeMn alloy was not really a new ternary compound as reported, but a solid solution Gd6(Fe0.5Mn0.5)23 which was only a point between Gd6Fe23 and Gd6Mn23. It was also found from DTA measurement that a reaction, Gd (Fe0.5Mn0.5)2 → liquid (rich Gd) + Gd6(Fe0.5Mn0.5)23, had taken place above 650.81 oC, and the educed Gd existed in educed part of GdFeMn sample. The results demonstrated the real structure of the GdFeMn compound as reported was Gd6(Fe0.5Mn0.5)23 compound.

2014 ◽  
Vol 602-603 ◽  
pp. 947-950
Author(s):  
Zhen Wang ◽  
Hai Yan Chen ◽  
Lin Qiang Gao ◽  
Xin Zou

BiFeO3 nanoparticles were successfully synthesized by a hydrothermal method by a mineralizer (KNO3). Structural characterization was performed by thermal analysis, powder X-ray diffraction (XRD) and scanning electron microscopy (TEM).The results showed that the products were perovskite structure BiFeO3 powders. Optimal conditions for the synthesis of single-phase BiFeO3 ceramics were obtained.


2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.


2008 ◽  
Vol 368-372 ◽  
pp. 995-997
Author(s):  
Cui Wei Li ◽  
Hong Xiang Zhai ◽  
Yang Zhou ◽  
Shi Bo Li ◽  
Zhi Li Zhang

In this study, free Ti/Si/Al/C powder mixtures with molar ratio of 3:0.4:0.8:1.8 were heated in Argon with various schedules, in order to reveal the possibility for the synthesis of Ti3Si0.4Al0.8C1.8 solid solution powder. X-ray diffraction (XRD) was used for the evaluation of phase identities of the powder after different treatments. Scanning electron microscopy (SEM) was used to observe the morphology of the Ti3Si0.4Al0.8C1.8 solid solution. XRD results showed that predominantly single phase samples of Ti3Si0.4Al0.8C1.8 was prepared after heating at 1400oC for 5 min in Argon and the lattice parameters of Ti3Si0.4Al0.8C1.8 lay between those of Ti3SiC2 and Ti3AlC2.


2005 ◽  
Vol 20 (10) ◽  
pp. 2741-2744 ◽  
Author(s):  
Huixing Lin ◽  
Wei Chen ◽  
Lan Luo

Phase-pure Ba2Ti9O20 powders were made by doping 3 wt% of V2O5 to a Ba:Ti = 2:9 molar composition, and the effects of the dopant on the phase formation were investigated. The study shows that BaTiO3, BaTi2O5, and BaTi4O9 were the intermediate phases before the formation of Ba2Ti9O20 for samples with or without V2O5. However, with V2O5 doping, the temperature at which Ba2Ti9O20 occurred were lowered from 1150 to 1050 °C and single phase Ba2Ti9O20 powders was easily obtained at 1150 °C for 2 h. Microstructure of the powders was examined by field emission scanning electron microscopy. No evidence of V2O5–Ba2Ti9O20 solid-solution was found by x-ray diffraction and energy-dispersive spectroscopy. The benefit of V2O5 to facilitate the Ba2Ti9O20 synthesis is most probably due to a vanadium-containing eutectic liquid phase which accelerates the migration of reactant species.


1980 ◽  
Vol 7 (1-3) ◽  
pp. 29-33
Author(s):  
R. Kužel ◽  
J. Broukal

The electrical properties of resistors comprising finely divided CdO and cadmium glass, were investigated. The change in a temperature coefficient of resistance from about −500 ppm/℃ to +70 ppm/℃ was realized by addition of a further component to the resistor paste. Differential thermal analysis, X-ray diffraction analysis and scanning electron microscopy were used for studying crystalline phases in glass containing CdO.


2016 ◽  
Vol 258 ◽  
pp. 440-443
Author(s):  
Ivona Černičková ◽  
Marek Adamech ◽  
Libor Ďuriška ◽  
Marian Drienovský ◽  
Dusan Janičkovič ◽  
...  

The work is aimed at searching for compositionally variant isostructural mutations of the cubic F-phase in both as-annealed (850°C/500 h) and DTA-cooled conditions of the Al72Pd9Co19 alloy. Recently, the mutations were reported for the U-phase in the Al69.8Pd13.8Co16.4 alloy annealed at 700°C for 2000 h. In the investigation, scanning electron microscopy including energy dispersive X-ray spectroscopy, powder X-ray diffraction, and differential thermal analysis (DTA) were used. Two isostructural mutations of the F-phase, FL (the product of L-parent) and FV (the product of V-parent), were identified (symbol L stands for liquid). On DTA-cooling, the bivariant heterogeneous transition (Lpart→V), the monovariant heterogeneous transformation (Lrest→V+FL), and the monovariant quasi-eutectoid transformation (Vrest→Al5Co2+FV) were recorded.


2012 ◽  
Vol 476-478 ◽  
pp. 379-382 ◽  
Author(s):  
Delin Lai ◽  
Yong Chen ◽  
Da Xiang Yang ◽  
Wei Ling Guo ◽  
Yu Xi Yu

The alumina (Al2O3) nanofibers were fabricated by electrospinning a viscous mixture of aluminum isopropoxide solution in 10% aqueous solution of PVA followed by calcination at 500~1000 °C. Tools such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric and differential thermal analysis (TG-DTA) were employed to characterize the obtained nanofibers. When the nanofibers were heat treated at 1000 °C, the as-prepared nanofibers have a diameter in the range of 30 ~ 100 nm, and are composed of α-Al2O3.


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