Fabrication of porous NiAl intermetallic compounds with a hierarchical open-cell structure by combustion synthesis reaction and space holder method

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.

Download Full-text

A study of combustion synthesis reaction in the Ti + C/Ti + Al system

Journal of Materials Science ◽

10.1023/b:jmsc.0000017769.40870.8d ◽

2004 ◽

Vol 39 (6) ◽

pp. 2073-2080 ◽

Cited By ~ 11

Author(s):

Chyi-Ching Hwang ◽

Shyan-Lung Chung

Keyword(s):

Combustion Synthesis ◽

Synthesis Reaction ◽

Combustion Synthesis Reaction

Download Full-text

Microstructure characteristics of products in Ti–Si system via combustion synthesis reaction

Journal of Materials Science ◽

10.1007/s10853-009-3289-y ◽

2009 ◽

Vol 44 (7) ◽

pp. 1902-1908 ◽

Cited By ~ 5

Author(s):

Q. L. Guan ◽

H. Y. Wang ◽

S. L. Li ◽

C. Liu ◽

Q. C. Jiang

Keyword(s):

Combustion Synthesis ◽

Synthesis Reaction ◽

Microstructure Characteristics ◽

Combustion Synthesis Reaction

Download Full-text

Combustion Synthesis of TiB2-TiC Ceramic

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.380-384.4323 ◽

2013 ◽

Vol 380-384 ◽

pp. 4323-4326 ◽

Cited By ~ 2

Author(s):

Su Li ◽

Jun Shou Li ◽

Fang Zhao ◽

Ming Yuan Wang

Keyword(s):

Combustion Synthesis ◽

Formation Mechanism ◽

Spherical Particles ◽

Molar Ratio ◽

Synthesis Reaction ◽

Combustion Synthesis Reaction ◽

Multiphase Ceramics

TiB2-TiC multiphase ceramics were prepared through altering the molar ratio of Mg and C and leached with suitable acid by the combustion synthesis reaction of Mg, C, TiO2 and B2O3. The samples were investigated by XRD and SEM, and the results showed the diameter of the TiB2 was 1.5μm and the shape of the TiC was irregular spherical particles. The diameter and the proportion of the TiB2 were increased with the increase of Mg powder. The formation mechanism of TiB2 has been studied. The optimized proportioning of the molar ratio of Mg and C was 3:2.

Download Full-text

Reaction mechanism in combustion synthesis of α-Si3N4 powder using NaN3

Journal of Materials Research ◽

10.1557/jmr.2008.0327 ◽

2008 ◽

Vol 23 (10) ◽

pp. 2720-2726 ◽

Cited By ~ 10

Author(s):

Shyan-Lung Chung ◽

Chih-Wei Chang ◽

F.J. Cadete Santos Aires

Keyword(s):

Reaction Mechanism ◽

Solid State ◽

Nitrogen Source ◽

Combustion Synthesis ◽

Synthesis Method ◽

Reducing Agent ◽

Synthesis Reaction ◽

Ammonium Halides ◽

Nitridation Reaction ◽

Combustion Synthesis Reaction

A combustion synthesis method for the synthesis of α-Si3N4 from a reactant compact composed of Si, NaN3, and NH4X and wrapped up with an igniting agent was investigated. Wrapping the reactant compact with the igniting agent (i.e., a mixture of Ti and C powders) was found necessary for the synthesis of Si3N4. In addition to NH4Cl, which was considered previously to function as a catalytic agent, other ammonium halides (i.e., NH4F, NH4Br, and NH4I) were found to be capable of catalyzing the synthesis reaction with NH4Cl being the most effective. Si3N4 could not be produced when NaN3 was replaced by C3H6N6. NaN3 was thus considered to exert an essential effect on the combustion synthesis reaction other than functioning as a solid-state nitrogen source as considered previously. It was proposed that Na vapor produced by decomposition of NaN3 reduces SiXx (formed by reaction of Si and NH4X), promoting the nitridation reaction to form Si3N4. NaN3 thus plays a role as a reducing agent in the synthesis reaction.

Download Full-text

Combustion Synthesis of α-Si3N4 Powder under Low Nitrogen Pressure

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.45.989 ◽

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.

Download Full-text

Effect of Mg on the Synthesis of TiB2 Powder by a Self-Propagating High-Temperature Synthesis Technique

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.347-350.1144 ◽

2013 ◽

Vol 347-350 ◽

pp. 1144-1147

Author(s):

Su Li ◽

Jun Shou Li ◽

Fang Zhao ◽

Ming Hui Ye

Keyword(s):

High Temperature ◽

Combustion Synthesis ◽

Formation Mechanism ◽

Molar Ratio ◽

Synthesis Reaction ◽

Hexagonal Crystal ◽

Temperature Synthesis ◽

High Temperature Synthesis ◽

Higher Temperature ◽

Combustion Synthesis Reaction

Micro-nanoTiB2 ceramic was prepared through increasing the molar ratio of Mg and leaching with suitable acid by the combustion synthesis reaction of Mg, TiO2 and B2O3, which could get higher temperature and purer product. The Samples were investigated by XRD and SEM, and the results showed the diameter of the TiB2 was 200 nm ~ 300 nm and the shape of the TiB2 was irregular hexagonal crystal. The diameter of the TiB2 was decreased with the increase of Mg powder. The formation mechanism of TiB2 has been studied.

Download Full-text