Self-propagating high temperature synthesis of SiC–Cu and SiC–Al cermets: Role of chemical activation

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.

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Parameter analysis of non-metallic inclusion formation in thermite alloys

E3S Web of Conferences ◽

10.1051/e3sconf/202128007015 ◽

2021 ◽

Vol 280 ◽

pp. 07015

Author(s):

Ihor Skidin ◽

Oksana Vodennikova ◽

Sergii Vodennikov ◽

Levan Saithareiev ◽

Shamil Telkov

Keyword(s):

High Temperature ◽

Parameter Analysis ◽

Growth Time ◽

Metallic Inclusion ◽

Temperature Synthesis ◽

Inclusion Formation ◽

High Temperature Synthesis ◽

Alumina Particles ◽

Average Size

The methodology of calculating parameters of the primary and secondary non-metallic inclusion formation in thermite alloys is offered. The regularities of the growth time of non-metallic inclusion in the form of corundum depending on its size, mass and quantity are analysed. It is shown that in the thermite alloy obtained by self-propagating high-temperature synthesis, the average size of corundum inclusions, surrounding the heterogeneous inclusions of chromium carbide, is 15.4 μm. It is shown that during the process of aluminothermic reactions of the SHS process a significant number of small inclusions of corundum is formed. It is shown that the alumina particles are dissolved in the alloy and they are the centers of crystallization and play the role of inoculating modifier.

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Ignition mechanism of mechanically activated Me–Si(Me = Ti, Nb, Mo) mixtures

Journal of Materials Research ◽

10.1557/jmr.2004.0209 ◽

2004 ◽

Vol 19 (5) ◽

pp. 1558-1566 ◽

Cited By ~ 27

Author(s):

U. Anselmi-Tamburini ◽

F. Maglia ◽

S. Doppiu ◽

M. Monagheddu ◽

G. Cocco ◽

...

Keyword(s):

High Temperature ◽

Reaction Mechanism ◽

Mechanical Activation ◽

Ignition Temperature ◽

Temperature Synthesis ◽

High Temperature Synthesis ◽

Ignition Mechanism ◽

Ignition Characteristics ◽

Different Response

The influence of mechanical activation on the characteristics and mechanism of ignition of self-propagating high-temperature synthesis processes of different silicides in the systems Me–Si (Me =Ti, Nb, Mo) was investigated. The results show that mechanical activation does not alter the mechanism involved but influences significantly the ignition characteristics. The influence, however, strongly depends on the stoichiometry of the mixtures. The composition Ti:Si = 1:2 shows the largest influence, with the ignition temperatures decreasing from 1400 °C for unmilled powders to about 600 °C for powders milled for several hours. The compositionsTi:Si = 5:3, Nb:Si = 1:2 show less pronounced decreases, while the compositionMo:Si = 1:2 shows no decrease. These differences are discussed in terms of the role of microstructure in the reaction mechanism and the different response of the systems to contamination, particularly from oxygen. The results suggest that for these systems self-ignition processes during milling cannot be explained only on the basis of the decrease in the ignition temperature.

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Role of the high-temperature synthesis of the titanium carbide phase in lowering the limits of detection of impurities in high-purity titanium dioxide

Journal of Applied Spectroscopy ◽

10.1007/bf00664967 ◽

1989 ◽

Vol 51 (5) ◽

pp. 1129-1131

Author(s):

I. A. Grikit ◽

A. S. Kozhevnikova ◽

S. N. Dotsenko ◽

Yu. I. Rys'eva

Keyword(s):

Titanium Dioxide ◽

High Temperature ◽

Titanium Carbide ◽

High Purity ◽

Carbide Phase ◽

Temperature Synthesis ◽

Limits Of Detection ◽

High Temperature Synthesis ◽

Purity Titanium

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Microstructure and Adhesion of NiAl/Al and NiAl/Ni Coatings Formed by SHS Process

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.660.185 ◽

2014 ◽

Vol 660 ◽

pp. 185-189

Author(s):

Tri Widodo Besar Riyadi ◽

Tao Zhang ◽

Sarjito

Keyword(s):

High Temperature ◽

Combustion Chamber ◽

Induction Heating ◽

Steel Substrate ◽

Intermetallic Phases ◽

Temperature Synthesis ◽

Argon Gas ◽

High Temperature Synthesis

The objective of thiswork was to investigate the microstructure and adhesion of NiAl coating whichformed by self propagation high temperature synthesis (SHS) process. Ni/Almixture and an underlayer material which used Ni and Al were compacted to forma bilayer pellet and subsequently put on a steel substrate. The Ni/Al reactionwas ignited using induction heating in a combustion chamber of argon gas. Themorphology and microstructure of the products were observed using SEM and XRD.The results showed that further reactions between NiAl coating and underlayermaterials formed several intermetallic phases. The role of Al and Ni underlayeron the microstructure, porosity and the adhesion between coating and thesubstrate was observed.

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