Combustion Synthesis of Ti(C,N) Powder

2007 ◽  
Vol 280-283 ◽  
pp. 1421-1424 ◽  
Author(s):  
Yan An Wang ◽  
Ke Xin Chen ◽  
He Ping Zhou
Keyword(s):  
Reaction Mechanism ◽  
Combustion Synthesis ◽  
Phase Formation ◽  
Combustion Temperature ◽  
Nitrogen Pressure ◽  
Nitrogen Atmosphere ◽  
Titanium Carbonitride ◽  
Synthesis Process ◽  
Reaction Parameters ◽  
N Powder

Titanium carbonitride powders were synthesized directly by a combustion synthesis process between titanium and carbon in a nitrogen atmosphere. The relationships between properties of the final product and the combustion reaction parameters were systematically investigated. Especially, the effects of nitrogen pressure on the phase formation and microstructure of the as-synthesized products were experimentally investigated. The reaction mechanism of Ti(C,N) was proposed through quench experiment, the variation of combustion temperature on time and thermodynamics analysis.

Combustion Synthesis of Si3N4 from Si/NH4Cl at Low Nitrogen Pressure

2008 ◽  
Vol 368-372 ◽  
pp. 1767-1770 ◽  
Author(s):  
Yi Xiang Chen ◽  
Jiang Tao Li ◽  
Zhi Ming Lin ◽  
Guang Hua Liu ◽  
S.L. Yang ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
Combustion Temperature ◽  
Profile Analysis ◽  
Combustion Velocity ◽  
Nitrogen Pressure ◽  
Analysis Method ◽  
Α Phase ◽  
Steady Combustion ◽  
Combustion Wave Velocity ◽  
Low Nitrogen

Combustion synthesis (CS) of Si3N4 was accomplished by using as-milled Si/NH4Cl as reactants at low nitrogen pressure. The additive of NH4Cl decreased the combustion temperature and promoted the Si nitridation. Full nitridation of Si was achieved by burning Si in pressurized nitrogen with 10 ~ 25 wt. % NH4Cl as additives while no Si3N4 diluent added. The maximum combustion temperature (Tc), the combustion velocity (u) together with the α-Si3N4 content and mean particle size (d50) of the powder products were found to be great dependent on the NH4Cl content added in the reactants. Fine Si3N4 powder products with α-phase content up to 85 wt. % were obtained via steady combustion mode. A mathematical approach named combustion wave velocity methods for the analysis of temperature profiles in CS was proposed and the reaction kinetics was discussed. The apparent activation energy calculated according to the temperature profile analysis method is 29.7 kJ/mol, which agrees well with the corresponding low temperature nitriding combustion of Si.

Combustion synthesis of Si3N4 powder

1997 ◽  
Vol 12 (3) ◽  
pp. 805-811 ◽  
Author(s):  
Wei-Chang Lee ◽  
Shyan-Lung Chung
Keyword(s):  
Reaction Mechanism ◽  
Combustion Synthesis ◽  
Combustion Temperature ◽  
Fine Particles ◽  
Minor Amount ◽  
Synthesis Reaction ◽  
Experimental Parameters ◽  
Combustion Synthesis Reaction ◽  
A Minor ◽  
Low Nitrogen

A combustion synthesis (SHS) process has been developed for the synthesis of Si3N4 powder under low nitrogen pressures. Si and NaN3 powders were used as the reactants, and NH4Cl powder was added as a catalytic agent. These powders were mixed and pressed into a cylindrical compact. The compact was wrapped up with an igniting agent (i.e., Ti + C), and the synthesis reaction was triggered by the combustion of the igniting agent. Addition of NH4Cl was found necessary for the combustion synthesis reaction under low nitrogen pressures (< 1.2 MPa). The product as synthesized is mostly in the form of agglomerated fine particles (0.1–1 μm in diameter) and is composed mainly of α-phase and a minor amount of β-phase. Effects of various experimental parameters (N2 pressure, NaN3, NH4Cl, and Si3N4 contents) on the product conversion and the combustion temperature were investigated. A possible reaction mechanism was proposed that explains the effects of the experimental parameters on the synthesis reaction.

Preparation of silicon boride SiBx (x = 3, 4, 5, 6) powders by chemical oven self-propagating combustion synthesis

2020 ◽  
Vol 111 (10) ◽  
pp. 792-798
Author(s):  
W. Liu ◽  
P. Feng ◽  
X. Ren ◽  
L. Zhu
Keyword(s):  
Combustion Synthesis ◽  
Combustion Temperature ◽  
Exothermic Reaction ◽  
Synthesis Process ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Quantitative Results ◽  
Adiabatic Combustion Temperature ◽  
Diffraction Peaks ◽  
Time And Energy

Abstract A new method was developed for quickly preparing a highemissivity silicon boride compound of SiBx (x = 3, 4, 5, 6) by highly exothermic Ti-TiO2-Si-Al chemical oven preheating. The SiBx combustion synthesis process and adiabatic combustion temperature were investigated. A large exothermic reaction occurred at the combustion temperature of 1 700 K. X-ray diffraction results indicate that an SiBx phase and a substantial amount of unreacted Si were identified in the products. By increasing the boron content until the Si-B ratio reached to 1 : 6, the diffraction peaks primarily indicated SiB6, SiB4, and Si11B33 in the final product. According to the spectra and quantitative results, the atomic chemical composition ratio of Si and B was close to the nominal composition. Thus, this method offers an efficient way to produce Si-B compounds with less time and energy consumption than current methods.

Combustion Synthesis of α-Si3N4 Powder under Low Nitrogen Pressure

2006 ◽  
Vol 45 ◽  
pp. 989-993
Author(s):  
Chih Wei Chang ◽  
Shyan Lung Chung
Keyword(s):  
Reaction Mechanism ◽  
Solid State ◽  
Combustion Synthesis ◽  
Fine Particles ◽  
Nitrogen Pressure ◽  
Synthesis Reaction ◽  
Α Phase ◽  
Experimental Parameters ◽  
Combustion Synthesis Reaction ◽  
Low Nitrogen

A combustion synthesis reaction has been developed for the α-Si3N4 powder under low nitrogen pressure. Si and solid state nitrogen source were used as the reactants, and ammonium halide powders were added as a catalytic agent. These powders were mixed and pressed into a cylindrical compact and wrapped up with an ignition agent (i.e., Ti + C). The synthesis reaction was triggered by combustion of the igniting agent. The product as synthesized is composed mostly of α-phase and in the form of agglomerated fine particles (0.1-1 μm in diameter). The effects of the additives and other experimental parameters on the process were investigated and a possible reaction mechanism was also proposed.

The mechanism of combustion synthesis of titanium carbonitride

1994 ◽  
Vol 9 (2) ◽  
pp. 431-435 ◽  
Author(s):  
M. Eslamloo-Grami ◽  
Z.A. Munir
Keyword(s):  
Solid Solution ◽  
Phase Stability ◽  
Defect Structure ◽  
Nitrogen Pressure ◽  
Nitrogen Atmosphere ◽  
Titanium Carbonitride ◽  
Complete Conversion ◽  
Step Process ◽  
Carbonitride Phase ◽  
Thermodynamic Phase

Titanium carbonitride, TiC0.5N0.5, is synthesized directly by a self-propagating reaction between titanium and carbon in a nitrogen atmosphere. Complete conversion to the carbonitride phase is achieved with the addition of TiN as diluent and with a nitrogen pressure ≥0.6 MPa. Thermodynamic phase-stability calculations and experimental characterizations of quenched samples support a proposed mechanism in which the formation of the carbonitride is a two-step process. The first step involves the formation of the nonstoichiometric carbide, TiC0.5, and is followed by the formation of the product by the incorporation of nitrogen in the defect-structure carbide to form the carbonitride solid solution.

Microstructure and formation mechanism of combustion-synthesized rodlike Ca α-sialon crystals

2001 ◽  
Vol 16 (7) ◽  
pp. 1928-1934 ◽  
Author(s):  
Kexin Chen ◽  
Haibo Jin ◽  
M. Oliveira ◽  
Heping Zhou ◽  
J. M. F. Ferreira
Keyword(s):  
Reaction Mechanism ◽  
Combustion Synthesis ◽  
Formation Mechanism ◽  
Particle Morphology ◽  
Morphological Features ◽  
Combustion Reaction ◽  
Synthesis Process ◽  
Two Dimensional ◽  
High Productivity ◽  
The Relationship

The fabrication of rodlike Ca α-sialon crystals through a combustion synthesis process is reported in this paper. The main morphological features in the product included rodlike crystals, two dimensional elongated platelets, and equiaxed particles. By proper adjustment of the combustion parameters, a high productivity of rodlike Ca α-sialon crystals in the final product could be achieved. The combustion reaction mechanism and the relationship between the combustion parameters and the particle morphology were investigated.

Effect of iron and cobalt addition on TiC combustion synthesis

1993 ◽  
Vol 8 (12) ◽  
pp. 3202-3209 ◽  
Author(s):  
Yoon Choi ◽  
Shi-Woo Rhee
Keyword(s):  
Activation Energy ◽  
Grain Size ◽  
Reaction Mechanism ◽  
Combustion Synthesis ◽  
Combustion Temperature ◽  
Grain Shape ◽  
Arrhenius Plot ◽  
Molar Ratio ◽  
Velocity Measurements ◽  
Cobalt Addition

Fe and Co metals were incorporated into a Ti and C mixture with a molar ratio of 1.0 over the range of 0 to 40 wt. % to study their effect on TiC combustion synthesis. The addition brought about the grain size decrease, change of grain shape (angular to spherical), and different distribution (agglomerated to isolated) of TiC grains. Both Fe and Co additives were distributed around TiC grains and served as a binder. It was observed that reaction between Ti and C was kinetically more favorable than any other reactions in the Ti–C–Fe or Ti–C–Co system. Based on the activation energy from an Arrhenius plot of In[(1−w)1/2u/Tc] vs 1/Tc, which was obtained by combustion temperature and wave velocity measurements, the reaction mechanism in combustion synthesis of TiC with the addition of 20 wt. % Fe and Co was suggested.

scholarly journals Combustion Synthesis of Aluminum Oxynitride in Loose Powder Beds

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4182
Author(s):  
Alan Wilmański ◽  
Magdalena Zarzecka-Napierała ◽  
Zbigniew Pędzich
Keyword(s):  
Combustion Synthesis ◽  
Metal Powder ◽  
Weight Ratio ◽  
Nitrogen Pressure ◽  
Alumina Powder ◽  
Metal Powders ◽  
Aluminum Oxynitride ◽  
Synthesis Conditions ◽  
Aluminum Metal ◽  
Loose Powder

This paper describes combusting loose powder beds of mixtures of aluminum metal powders and aluminum oxide powders with various grain sizes under various nitrogen pressure. The synthesis conditions required at least 20/80 weight ratio of aluminum metal powder to alumina powder in the mix to reach approximately 80 wt% of γ-AlON in the products. Finely ground fused white alumina with a mean grain size of 5 μm was sufficient to achieve results similar to very fine alumina with 0.3 μm grains. A lower nitrogen pressure of 1 MPa provided good results, allowing a less robust apparatus to be used. The salt-assisted combustion synthesis upon addition of 10 wt% of ammonium nitrite resulted in a slight increase in product yield and allowed lower aluminum metal powder content in mixes to be ignited. Increasing the charge mass five times resulted in a very similar γ-AlON yield, providing a promising technology for scaling up. Synthesis in loose powder beds could be utilized for effective production of relatively cheap and uniform AlON powder, which could be easily prepared for forming and sintering without intensive grounding and milling, which usually introduce serious contamination.

Chemically activated combustion synthesis of AlON under high nitrogen pressure

2021 ◽  
Vol 232 ◽  
pp. 111560
Author(s):  
Tigran G. Akopdzhanyan ◽  
Sergey I. Rupasov ◽  
Stepan Vorotilo
Keyword(s):  
Combustion Synthesis ◽  
Nitrogen Pressure ◽  
High Nitrogen ◽  
High Nitrogen Pressure
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