scholarly journals Исследование фазового состава интерфейсного слоя, полученного при горячем прессовании Cr и Si

Author(s):  
Ф.Ю. Соломкин ◽  
А.Ю. Самунин ◽  
Н.В. Зайцева ◽  
Н.В. Шаренкова ◽  
Г.Н. Исаченко ◽  
...  

The possibility of synthesizing layers of the medium-temperature thermoelectric CrSi2 by hot pressing of the initial components (Cr and Si) has been investigated. The phase composition of samples obtained by hot pressing of Cr and Si before and after annealing in the region of their contact boundary has been investigated by X-ray analysis. It is shown that, under certain conditions, low-temperature synthesis of a CrSi2 layer with a thickness of 50 to 300 μm is possible at the interface between Cr and Si. The synthesis occurs at a temperature significantly lower than that given in the phase diagram, which opens up new technological possibilities for obtaining the CrSi2 compound.

2007 ◽  
Vol 5 (1) ◽  
pp. 169-176 ◽  
Author(s):  
Abdülhadi Baykal ◽  
Yüksel Köseoğlu ◽  
Mehmet Şenel

AbstractHeating hydrous manganese (II) hydroxide gel at 85 °C for 12 hours produces Mn3O4 nanoparticles. They were characterized by X-ray powder diffraction (XRD) and infrared spectroscopy (FTIR). The particle size estimated from the SEM and X-ray peak broadening is approximately 32 nm, showing them to be nanocrystalline. EPR measurements confirm a typical Mn2+signal with a highly resolved hyperfine structure.


2014 ◽  
Vol 32 (4) ◽  
pp. 526-532 ◽  
Author(s):  
Magdalena Król ◽  
Justyna Morawska ◽  
Włodzimierz Mozgawa ◽  
Waldemar Pichór

AbstractThe paper investigates the properties of sodium zeolites synthesized using the hydrothermal method under autogenous pressure at low temperature with NaOH solutions of varying concentrations. During this modification, zeolites X, Na-P1 and hydroxysodalite were synthesized. The synthesis parameters, and thus, phase composition of resulting samples, significantly affected the specific surface area (SSA) and cation exchange capacity (CEC). SSA increased from 2.9 m2/g to a maximum of 501.2 m2/g, while CEC rose from 16 meq/100 g to a maximum of 500 meq/100 g. The best properties for use as a sorbent were obtained for perlite waste modified with 4.0 M NaOH at 70 °C or 80 °C.


2010 ◽  
Vol 136 ◽  
pp. 14-17 ◽  
Author(s):  
Yu Zhong Li ◽  
Xiao Chun Zhou

A novel red emitting phosphor, Ca2SnO4: Eu3+, was prepared by the low temperature solid state reaction. X-ray powder diffraction (XRD) analysis confirmed the formation of Ca2SnO4: Eu3+. Scanning electron-microscopy (SEM) observation indicated a narrow size distribution of about 500 nm for the particles with spherical shape. Under 396 nm excitation, the Ca2SnO4: Eu3+ phosphor exhibits novel red emission at about 613 nm which is assigned to the 5D0→7F2 electric-dipole transition. Furthermore, the emission transition 5D0→7F2 has been found to be more prominent over the normal orange emission transition 5D0→7F1.


2017 ◽  
Vol 188 ◽  
pp. 454-459 ◽  
Author(s):  
Junqian Zhao ◽  
Huaina Yu ◽  
Shusheng Pan ◽  
Shang Zhou ◽  
Li Zhong ◽  
...  

2021 ◽  
Vol 129 (2) ◽  
pp. 207
Author(s):  
В.А. Кравец ◽  
Е.В. Иванова ◽  
К.Н. Орехова ◽  
Г.А. Гусев ◽  
В.В. Васькевич ◽  
...  

The main purpose of this work was to carry out a low-temperature synthesis of glass ceramics containing YNbO4:Eu3+ crystallites and to study the structural and luminescent properties of the obtained samples. Within the framework of this work, the inclusions that crystallized under the conditions of low-temperature synthesis in the systems of SiO2-Na2O-K2O-Y2O3-Nb2O5-Eu2O3 (SiNaK) and B2O5-Na2O-Y2O3-Nb2O5-Eu2O3 (BNa) were investigated for the first time. It was shown that YNbO4: Eu3+ crystallized in both considered systems. In the SiNaK system the crystallization of SiO2 also occurred (quartz, crisstabolite, and tridymite) under the selected conditions. The BNa system proved to be the most promising for the synthesis of activated glass-ceramics with YNbO4, since the required crystallites crystallized only in ithis system. The luminescent properties of crystalline inclusions were investigated using the local cathodoluminescence technique. The composition and structure of glass ceramics were studied by electron-probe microanalysis and X-ray diffraction phase analysis.


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