Self-Propagating High-Temperature Synthesis: Non-Equilibrium Processes and Equilibrium Products

2006 ◽  
Vol 45 ◽  
pp. 36-44 ◽  
Author(s):  
A.G. Merzhanov
Keyword(s):  
Wave Propagation ◽  
High Temperature ◽  
Structure Formation ◽  
Front Propagation ◽  
Combustion Time ◽  
Temperature Synthesis ◽  
Equilibrium Processes ◽  
High Temperature Synthesis ◽  
Non Equilibrium

The nature of SHS process was studied, and conditions under which equilibrium and non-equilibrium regimes take place for wave propagation and structure formation of SHS products are under consideration. The important role of cooling down time is shown. Depending on its magnitude, either autoannealing or autoquenching processes can take place in the products after combustion front propagation. The correlation between transition from non-equilibrium to equilibrium state of the product with prolongation of cooling time was examined as well as character of products and processes was indicated in dependence on relationship between the characteristic times of combustion, time of cooling down, and structure formation in SHS product.

Structure Formation during High-Temperature Synthesis in an Activated Ti + Al Powder Mixture

2019 ◽  
Vol 55 (11) ◽  
pp. 1097-1103
Author(s):  
V. Yu. Filimonov ◽  
M. V. Loginova ◽  
A. V. Sobachkin ◽  
S. G. Ivanov ◽  
A. A. Sitnikov ◽  
...  
Keyword(s):  
High Temperature ◽  
Structure Formation ◽  
Powder Mixture ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Al Powder

ChemInform Abstract: Self-Propagating High Temperature-Synthesis of Si3N4: Role of Ammonium Salt Addition.

ChemInform ◽  
2010 ◽  
Vol 32 (23) ◽  
pp. no-no
Author(s):  
I. G. Cano ◽  
S. Perez Baelo ◽  
M. A. Rodriguez ◽  
S. de Aza
Keyword(s):  
High Temperature ◽  
Ammonium Salt ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Salt Addition

Preparation of (Mo,Nb)Si2 Ternary Alloys by Self−Propagating High−Temperature Synthesis

2011 ◽  
Vol 266 ◽  
pp. 219-222
Author(s):  
Pei Zhong Feng ◽  
Shuai Zhang ◽  
Xiao Hong Wang ◽  
Wei Sheng Liu ◽  
Jie Wu
Keyword(s):  
High Temperature ◽  
Flame Front ◽  
Propagation Velocity ◽  
Combustion Temperature ◽  
Front Propagation ◽  
Ternary Alloys ◽  
Combustion Mode ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Front Propagation Velocity

An experimental study on the preparation of (Mo,Nb)Si2 ternary alloys was conducted by self-propagating high-temperature synthesis method from elemental powder compacts of different stoichiometries. And the combustion mode, combustion temperature, flame-front propagation velocity and product structure were discussed. The results show that (Mo,Nb)Si2 ternary alloys are characterized by an unsteady state combustion mode with a spiral−trajectory reaction front from top to bottom. The combustion temperature and flame−front propagation velocity decrease with the addition of coarse niobium powder. The combustion temperature and flame-front propagation velocity of MoSi2 are 1629K and 3.13mm/s respectively. However, those of (Mo0.8Nb0.2)Si2 alloy are 1460K and 1.97mm/s. The solid solubility of niobium in MoSi2 is less than 2.5at.%, and the combustion synthesis produce still remains Cllb single-phase structure in (Mo1-x,Nbx)Si2(x<0.075) sample. The C40-type structure appears in (Mo0.925,Nb0.075)Si2 compact and the intensity of diffraction peaks of C40-type phase gradually reinforces with the increase of niobium content. Combustion synthesis is an effective technology for producing (Mo,Nb)Si2 ternary alloys.

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