Fast synthesis of MgAl2O4‒W and MgAl2O4‒W‒W2B composite powders by self-propagating high-temperature synthesis reactions

2018 ◽  
Vol 44 (6) ◽  
pp. 6508-6513 ◽  
Author(s):  
J. Ghorbantabar Omran ◽  
M. Shafiee Afarani ◽  
M. Sharifitabar
2016 ◽  
Vol 675-676 ◽  
pp. 623-626 ◽  
Author(s):  
Tawat Chanadee ◽  
Sutham Niyomwas

Silicon-silicon carbide (Si-SiC) composite powders were synthesized by in-situ self- propagating high-temperature synthesis using rice husk ash (RHA)/carbon/Mg as precursors in argon atmosphere. The as-SHS powders were leached by two leaching steps. The microstructure and chemical composition of the obtained Si-SiC composite powders were examined using scanning electron microscope (SEM) and x-ray diffractometer (XRD), respectively.


2016 ◽  
Vol 685 ◽  
pp. 719-723 ◽  
Author(s):  
Maxim G. Krinitcyn ◽  
Gennadii A. Pribytkov ◽  
Vasiliy G. Durakov

A structure of Ti-TiC coatings with different content of titanium binder, overlaid of composite powders, which were obtained by self-propagating high-temperature synthesis, was investigated. The structure was studied by X-ray analysis and metallography. A size of the carbide particles in coatings, hardness of coatings and rate of wear were measured.


Author(s):  
Pan Yang ◽  
Guoqing Xiao ◽  
Donghai Ding ◽  
Yun Ren ◽  
Zhongwei Zhang ◽  
...  

The mechanism of self-propagating high-temperature synthesis (SHS) of AlB2‒Al2O3 composite powders was studied by means of a combustion front quenching method (CFQM). The results showed that combustion reaction started with the melting of B2O3 and Al particles. As the combustion reaction proceeded, the interpenetration of Al and B2O3 in melts happened. The XRD results of the product revealed the reflections of Al2O3, suggesting there had been an exchange of oxygen atoms between Al and B, and evidencing the reaction, B2O3 (l) + 2Al (l) → 2B (s) + Al2O3 (l). Under higher temperature, some of B2O3 volatilized and reacted with B forming gaseous B2O2, which deposited on the surface of Al to precipitate Al2O3 and B. Then B made available dissolved into Al melt, and reacted with the Al in melt to precipitate AlB12 particles. Finally, AlB12 transforms to AlB2 at the peritectic temperature under high cooling rate. Thus, this combustion reaction can be described by the dissolution-precipitation mechanism. In the final products, besides AlB2 and Al2O3 particles, some of Al was also detected. A model corresponding to the dissolutionprecipitation mechanism was proposed, and the ignition temperature of the combustion reaction was determined to be around 800 °C. Ill. 13. Ref. 47.


2016 ◽  
Vol 685 ◽  
pp. 578-582 ◽  
Author(s):  
Ljudmila Shiganova ◽  
George Bichurov ◽  
Irina Kerson ◽  
Vladislav Novikov ◽  
Anton Ermoshkin

The composite powder of AlN-BN is of interest from the point of view of the use for sintering the AlN-BN composite ceramics. The ceramics compared with AlN ceramics would have better thermal shock resistance, less britlleness, better machinability, good heat conductivity and tribological properties. Possibility of obtaining a composite powder of AlN-BN with the application of process of self-propagating high-temperature synthesis (SHS) from powder mixtures of NaN3 and precursors of aluminum and boron was investigated. Halide salts AlF3, Na3AlF6, KBF4 and NH4BF4 were used as the precursors. It was shown that these mixtures are capable of burning and obtaining agglomerated composite powders from nanosized (50-170 nm) particles.


2018 ◽  
Vol 934 ◽  
pp. 66-70
Author(s):  
Singsarothai Saowanee ◽  
Niyomwas Sutham ◽  
Tawat Chanadee

ZrB2-ZrC composite powders were synthesized from zircon sand by self-propagating high-temperature synthesis (SHS). The reactions were verified and the feasibility of obtaining the predicted products was calculated from the adiabatic temperature (Tad) and the equilibrium composition using the HSC®chemistry program. The results show that the SHS products consisted of ZrB2, ZrC, ZrO2, ZrSiO4, MgO, and Mg2SiO4. Leaching the products with 0.5 M of HCl solution eliminated the by-product of MgO and the intermediate Mg2SiO4phases. The phase composition of the products was characterized by X-ray diffraction (XRD) and the morphologies were characterized by scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX).


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