High-temperature synthesis, single-crystal X-ray and neutron powder diffraction, and materials properties of Sr3Ln10Si18Al12O18N36 (Ln = Ce, Pr, Nd)—novel sialons with an ordered distribution of Si, Al, O, and N

2000 ◽  
Vol 10 (6) ◽  
pp. 1357-1364 ◽  
Author(s):  
Rainer Lauterbach ◽  
Elisabeth Irran ◽  
Paul F. Henry ◽  
Mark T. Weller ◽  
Wolfgang Schnick
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Powder Diffraction ◽  
Neutron Powder Diffraction ◽  
Temperature Synthesis ◽  
Materials Properties ◽  
X Ray ◽  
High Temperature Synthesis

scholarly journals Single-Crystal Structure of HP-Sc2TeO6 Prepared by High-Pressure/High-Temperature Synthesis

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1554
Author(s):  
Raimund Ziegler ◽  
Martina Tribus ◽  
Clivia Hejny ◽  
Gunter Heymann
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Single Crystal ◽  
Ambient Pressure ◽  
Normal Pressure ◽  
Monoclinic Space Group ◽  
Temperature Synthesis ◽  
X Ray ◽  
High Temperature Synthesis ◽  
High Pressure High Temperature

The first high-pressure scandium tellurate HP-Sc2TeO6 was synthesized from an NP-Sc2TeO6 normal-pressure precursor at 12 GPa and 1173 K using a multianvil apparatus (1000 t press, Walker-type module). The compound crystallizes in the monoclinic space group P2/c (no. 13) with a = 729.43(3), b = 512.52(2), c = 1095.02(4) pm and β = 103.88(1)°. The structure was refined from X-ray single-crystal diffractometer data: R1 = 0.0261, wR2 = 0.0344, 568 F2 values and 84 variables. HP-Sc2TeO6 is isostructural to Yb2WO6 and is built up from TeO6 octahedra, typical for tellurate(VI) compounds. During synthesis, a reconstructive transition from P321 (normal-pressure modification) to P2/c (high-pressure modification) takes place and the scandium–oxygen distances as well as the coordination number of scandium increase. However, the coordination sphere around the Te6+ cations gets only slightly distorted. High-temperature powder XRD investigations revealed a back-transformation of HP-Sc2TeO6 to the ambient-pressure modification above 973 K.

New X-ray powder diffraction data for Mo2.85Al1.91Si4.81

2006 ◽  
Vol 21 (3) ◽  
pp. 238-240
Author(s):  
S. A. Tayebifard ◽  
K. Ahmadi ◽  
R. Yazdani-Rad ◽  
M. Doroudian
Keyword(s):  
High Temperature ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
The Self ◽  
Powder Diffraction Data ◽  
Temperature Synthesis ◽  
Automatic Indexing ◽  
X Ray ◽  
High Temperature Synthesis ◽  
Good Agreement

X-ray powder diffraction data for Mo2.85Al1.91Si4.81 are reported. The new Mo2.85Al1.91Si4.81 compound was successfully prepared using the self-propagating high-temperature synthesis (SHS) technique. The starting atomic mixture of reactant powders was Mo+2(1−x)Si+2xAl with x=0.3. The final powder compound obtained by the SHS technique was determined to be Mo2.85Al1.91Si4.81 by ICP-AES. X-ray powder diffraction pattern of Mo2.85Al1.91Si4.81 was recorded using an X-ray powder diffractometer, Cu Kα radiation, and analyzed by automatic indexing programs. Mo2.85Al1.91Si4.81 was found to be hexagonal with a=4.6929(2) Å and c=6.5515(4) Å. The XRD results are in good agreement with those of Mo2.85Ga2Si4.15.

scholarly journals SHS robust modes to restore molybdenum by combustion wave in MoO3 – Al system

2020 ◽  
Vol 15 (4) ◽  
pp. 27-32
Author(s):  
Irina V. Milyukova ◽  
Marina P. Boronenko
Keyword(s):  
Spectral Analysis ◽  
High Temperature ◽  
Combustion Wave ◽  
Synthesis Process ◽  
Temperature Synthesis ◽  
Preliminary Heating ◽  
X Ray ◽  
Molybdenum Metal ◽  
High Temperature Synthesis ◽  
Oxide Phases

The work is devoted to the technology for the reduction of molybdenum from oxides by the method of self-propagating high-temperature synthesis in the MoO3 AI system with the addition of aluminum. The experiment was carried out in two modes: in a reactor at different pressures without preliminary heating and in a furnace in air until the initiation of the SH-synthesis process. Samples of molybdenum metal were obtained in different synthesis modes. X-ray phase and X-ray spectral analysis showed that molybdenum is the main phase in the synthesized samples. The presence of slag oxide phases Al2O3 and MoO2 was detected.

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