Specific features of the behavior of synthetic diamond in a self-propagating high-temperature synthesis (SHS) combustion wave

1992 ◽  
Vol 63 (5) ◽  
pp. 1106-1110 ◽  
Author(s):  
K. L. Padyukov ◽  
E. A. Levashov ◽  
I. P. Borovinskaya ◽  
A. G. Kost
2020 ◽  
Vol 15 (4) ◽  
pp. 27-32
Author(s):  
Irina V. Milyukova ◽  
Marina P. Boronenko

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.


2000 ◽  
Vol 108 (1255) ◽  
pp. 290-297
Author(s):  
Yasuhiro TANABE ◽  
Nobuko OKADA ◽  
Akira MUKOHFUJIWARA ◽  
Takashi AKATSU ◽  
Eiichi YASUDA

1999 ◽  
Vol 14 (4) ◽  
pp. 1516-1523 ◽  
Author(s):  
Yasuhiro Tanabe ◽  
Takashi Sakamoto ◽  
Nobuko Okada ◽  
Takashi Akatsu ◽  
Eiichi Yasuda ◽  
...  

Titanium carbide foams are synthesized by a self-propagation high-temperature synthesis technique using carbon black, which generates gases during the synthesis. The synthesis is performed under terrestrial and microgravity conditions. The effects of gravity on the synthesis are evaluated in this study. The foaming is mainly caused by H2O and CO gases from the carbon black. The elongation of the products increases with decreasing environmental pressure and increasing amount of generated gases. Since the gas flows out along the direction of the combustion wave propagation, the products expand only along this direction. The propagation velocity of the combustion wave increases with increasing amount of generated gases and environmental pressure, which is due to the amount of molten Ti transporting into the reaction/preheat zone. Under higher environmental pressures, thermal convection of the environmental gases mainly affects the propagation velocity. However, at lower pressures, the behavior of the molten Ti has a great effect compared with the gases surrounding the specimens.


2020 ◽  
Vol 90 (7) ◽  
pp. 1189
Author(s):  
О.Е. Квашенкина ◽  
Е.Д. Эйдельман ◽  
В.С. Осипов ◽  
П.Г. Габдуллин ◽  
Б.Б. Хина

To simulate self-propagating high-temperature synthesis (solid flame combustion), a layered model is taken as the basis in which the product is formed between the layers of the starting reagents due to solid-phase diffusion in non-isothermal conditions, while the combustion wave propagates along these layers.It turned out that the cords from layers of aluminum and nickel with a thickness of up to 50µmv will completely turn into a high-temperature melt The calculation results will optimize the processes welding-soldering of heat-sensitive materials and parts of electronic components of various devices.


2011 ◽  
Vol 13 (3-4) ◽  
pp. 161
Author(s):  
Z.A. Mansurov ◽  
D.S. Abdulkarimova ◽  
O. Odawara ◽  
A. Gubarevich ◽  
A.S. Rogachev ◽  
...  

Preparation of TiB2-Al2O3 and CrB2-Al2O3 composites with a broad range of phase composition was  conducted by self-propagating high-temperature synthesis (SHS) involving reaction of different types. The formation of fibrous crystals of aluminum oxide with length of about 10-25 microns and with diameter of 200-500 nm at self-propagating high-temperature synthesis in the system 2B2O3-Cr2O3-6A1 was established. Thermite mixtures of Al-TiO2 and Al-TiO2-B2O3 were incorporated with the Ti-B combustion system to produce the composites of TiB2-Al2O3, within which the increase of the thermite mixture for a higher content of Al2O3 decreased the reaction temperature and combustion wave velocity. This implies that the thermite reaction of Al with TiO2 reduces the exothermicity of the overall SHS process. It was found that adoption of B2O3 as one of the thermite reagents improved the product formation effectively. For investigate the combustion wave in 0.75TiO2-0.25Ti-2B-Al system the «quenching» method was used. The XRD analysis shows that the final products containing diborides and aluminium oxide.


Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 210 ◽  
Author(s):  
Chun-Liang Yeh ◽  
Yin-Chien Chen

The formation of NbB2–MgAl2O4 composites from the MgO-added thermite-based reaction systems was investigated by self-propagating high-temperature synthesis (SHS). Two thermite mixtures, Nb2O5/B2O3/Al and Nb2O5/Al, were, respectively, adopted in Reactions (1) and (2). The XRD analysis confirmed the combination of Al2O3 with MgO to form MgAl2O4 during the SHS process and that excess boron of 30 atom.% was required to yield NbB2–MgAl2O4 composites with negligible NbB and Nb3B4. The microstructure of the composite reveals that rod-shaped MgAl2O4 crystals are closely interlocked and granular NbB2 are embedded in or scattered over MgAl2O4. With the addition of MgAl2O4, the fracture toughness (KIC) of 4.37–4.82 MPa m1/2 was obtained for the composites. The activation energies Ea = 219.5 ± 16 and 167.9 ± 13 kJ/mol for Reactions (1) and (2) were determined from combustion wave kinetics.


1991 ◽  
Vol 27 (3) ◽  
pp. 326-327
Author(s):  
A. P. Aleev ◽  
A. A. Kudryavtsev ◽  
V. M. Mal'tsev ◽  
V. M. Puchkov

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