Self-propagating High-temperature Synthesis of La1−xSrxMnyFe1−yO3 Perovskites for Soot Combustion Catalyst

2012 ◽  
Vol 31 (4-5) ◽  
pp. 513-518
Author(s):  
T. Hirano ◽  
T. Tosho ◽  
T. Watanabe ◽  
T. Akiyama
Keyword(s):  
High Temperature ◽  
Specific Area ◽  
Oxide Phase ◽  
Xrd Analysis ◽  
Soot Combustion ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Dta Analysis ◽  
Perovskite Type ◽  
Shs Method

AbstractThe La1−xSrxMnyFe1−yO3 samples of perovskite-type oxides were synthesized by Self-propagating High-temperature Synthesis (SHS) method. In this study, first, we synthesized B-site substituted perovskite-type oxides, LaMnxFe1−xO3. The SHS method successfully synthesized LaMnxFe1−xO3. The most active composition for soot combustion among synthesized samples of LaMnxFe1−xO3 was x = 0.4, LaMn0.4Fe0.6O3, from model-soot combustion experiment with TG/DTA analysis. We then examined the effect of A-site substitution by Sr on LaMn0.4Fe0.6O3 perovskite. The SHS of La1−xSrxMn0.4Fe0.6O3 was successfully ignited, propagated and completed. XRD peaks of perovskite-type oxide phase was detected in all the synthesized La1−xSrxMn0.4Fe0.6O3 but unreacted material, SrCO3, was also detected in the sample above x = 0.6 from XRD analysis. The soot combustion activity of Sr-doped LaMn0.4Fe0.6O3 was not enhanced according to the impurity in the samples. The most active composition among synthesized samples of La1−xSrxMnyFe1−yO3 was LaMn0.4Fe0.6O3 which exhibited lower activation energy than conventional Pt/Al2O3 catalyst, that is, LaMn0.4Fe0.6O3 synthesized by SHS method had superior soot combustion activity despite its relatively small specific area.

Preparation and Microwave Permittivity of SiC-AlN Solid Solution Powders

2007 ◽  
Vol 336-338 ◽  
pp. 310-312
Author(s):  
Xiao Kui Liu ◽  
Wan Cheng Zhou ◽  
Fa Luo ◽  
Dong Mei Zhu
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Carbon Black ◽  
Atomic Ratio ◽  
Nitrogen Atmosphere ◽  
Argon Atmosphere ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Microwave Permittivity ◽  
Shs Method

SiC-AlN solid solution powders were prepared from the mixtures of aluminum, silicon and carbon black in a nitrogen atmosphere with preheating self-propagating high temperature synthesis (SHS) method. The powders synthesized with different ratios of Al/Si were mixed with paraffin wax and the microwave permittivity of the mixtures was measured at the frequency of 8.2~12.4GHz. The results were contrasted with that of SiC powders synthesized by preheating SHS in argon and nitrogen atmosphere respectively. The ε′, ε″, and the tgδ (ε″/ε′) of the mixture of SiC prepared in a nitrogen atmosphere are highest, followed with those of the SiC-AlN solid solution powders and the SiC powders prepared in an argon atmosphere. Along with the increase of atomic ratio of Al/Si, the ε′, ε″, and tgδ of SiC-AlN solid solution decrease. We believe that, with the increase of AlN dissolved, the concentration of carriers and the effect of dielectric relaxation will decrease because of the two contrary dopants.

Immobilization of Radioactive Wastes into Perovskite Synrock by the SHS Method

2005 ◽  
Vol 475-479 ◽  
pp. 1627-1630 ◽  
Author(s):  
Rui Zhu Zhang ◽  
Zhi Meng Guo ◽  
Cheng Chang Jia ◽  
Guangfeng Lu
Keyword(s):  
High Temperature ◽  
Synthesis Process ◽  
Temperature Synthesis ◽  
Geological Disposal ◽  
Major Phase ◽  
Leach Rate ◽  
High Temperature Synthesis ◽  
Waste Loading ◽  
Shs Method

This paper researched the fabrication of perovskite synrock by self-propagating high temperature synthesis (SHS) and the characterization of the products. This synthesis process is simpler, the fabricated synrock can immobilize waste loading up to 35wt% SrO with satisfied physical properties (density>4.2g•cm-3, open porosity<0.2%, Leach rate<1.0 g•m-2•d-1). The structure analyses by XRD and SEM/EDS show that the major phase is perovskite which well agrees with the design. It proves that SHS offer a suitable Sr-waste synroc which is favorable for geological disposal.

Nickel-Containing Systems in Reaction of Partial Oxidation of Hydrocarbons

2015 ◽  
Vol 670 ◽  
pp. 33-38 ◽  
Author(s):  
Sergey Galanov ◽  
Olga I. Sidorova ◽  
Vera A. Batyreva
Keyword(s):  
High Temperature ◽  
Average Particle Size ◽  
Reaction Medium ◽  
Oxide Phase ◽  
Average Particle ◽  
Catalytic Layer ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Catalytically Active ◽  
Catalyst Systems

Nickel dispersion, which provides total catalytically active metal surface, is significant for partial catalytic oxidation of natural gas to obtain high purpose products yield and productivity in syngas. The interaction of reaction medium under high reaction temperatures during 20-25 hours promotes the increase of total square of active Ni component for block catalysts obtained with self-propagating high-temperature synthesis, which allows achieving productivity in syngas 7.1·103cm3(syngas)/cm3(catalyst)·hour. It is observed that for catalyst systems obtained with precipitation, chemical composition of oxide phase influences the particles size of metal nickel. For granular catalysts obtained through precipitation after 25-hour exploitation, average particle size (according to CSR) metal nickel is 3-4.5 times smaller than Ni in catalysts obtained with self-propagating high-temperature synthesis. This allows achieving productivity in syngas 8.1·103cm3/сm3·hour, when there is average temperature decrease over the catalytic layer by ~100°С in comparison with blocks acquired through self-propagating high-temperature synthesis.

Determination of Non-Stoichiometry of Tubular Titanium Carbide Formed by Self-Propagating High Temperature Synthesis

2007 ◽  
Vol 534-536 ◽  
pp. 1301-1304
Author(s):  
Y. Choi ◽  
Nam Ihn Cho
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Temperature ◽  
Titanium Carbide ◽  
Combustion Temperature ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Scanning Electron ◽  
Shs Method

Titinium carbide (TiCx) was produced by self-propagating high temperature synthesis (SHS) method. The morphology and non-stoichiometric number of the SHS product were observed by scanning electron microscopy and neutron diffractometry, respectively. Tubular titanium carbide with hole inside was formed with different non-stoichiometric number (x), which value increased with combustion temperature.

scholarly journals Peculiarities of Self-Propagating High-Temperature Synthesis and Structure Formation of TiB2-Al2O3 and CrB2-Al2O3 Composites

2011 ◽  
Vol 13 (3-4) ◽  
pp. 161
Author(s):  
Z.A. Mansurov ◽  
D.S. Abdulkarimova ◽  
O. Odawara ◽  
A. Gubarevich ◽  
A.S. Rogachev ◽  
...  
Keyword(s):  
High Temperature ◽  
Combustion Wave ◽  
Xrd Analysis ◽  
Product Formation ◽  
Combustion System ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Different Types ◽  
Combustion Wave Velocity ◽  
Quenching Method

Preparation of TiB2-Al2O3 and CrB2-Al2O3 composites with a broad range of phase composition was  conducted by self-propagating high-temperature synthesis (SHS) involving reaction of different types. The formation of fibrous crystals of aluminum oxide with length of about 10-25 microns and with diameter of 200-500 nm at self-propagating high-temperature synthesis in the system 2B2O3-Cr2O3-6A1 was established. Thermite mixtures of Al-TiO2 and Al-TiO2-B2O3 were incorporated with the Ti-B combustion system to produce the composites of TiB2-Al2O3, within which the increase of the thermite mixture for a higher content of Al2O3 decreased the reaction temperature and combustion wave velocity. This implies that the thermite reaction of Al with TiO2 reduces the exothermicity of the overall SHS process. It was found that adoption of B2O3 as one of the thermite reagents improved the product formation effectively. For investigate the combustion wave in 0.75TiO2-0.25Ti-2B-Al system the «quenching» method was used. The XRD analysis shows that the final products containing diborides and aluminium oxide.

Phase Formation and Thermodynamic Analysis of Self-propagating High-temperature Synthesis Al–Zr–N System Composites

1998 ◽  
Vol 13 (9) ◽  
pp. 2610-2613 ◽  
Author(s):  
Kexin Chen ◽  
Changchun Ge ◽  
Jiangtao Li
Keyword(s):  
High Temperature ◽  
Melting Point ◽  
Phase Formation ◽  
Combustion Temperature ◽  
Xrd Analysis ◽  
The Self ◽  
Composite Ceramics ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
The Relationship

The self-propagating high temperature synthesis (SHS) of Al–Zr–N system composite ceramics was investigated in this paper. The melting point of Al was low (Tm = 660 °C), while that of Zr was high (Tm =1855 °C). Therefore, Al will melt and coalesce during reaction, which inhibit diffusion of nitrogen from outside the metal compact to interior due to collapse of the pore openings, while Zr will not melt under the combustion temperature which is lower than its melting point. It will not affect the permeation of nitrogen under the conditions. Accordingly, the ratio of Al and Zr in the initial mixed powders will affect the permeation of nitrogen from outside the sample to the interior, which results in different phase formation of the products. In this study, the relationship between the combustion parameters and the phase formation of the products will be experimentally determined through XRD analysis, and then thermodynamically analyzed.

scholarly journals Self-propagating high-temperature synthesis of LaMO3 perovskite-type oxide using heteronuclearcyano metal complex precursors

2015 ◽  
Vol 649 ◽  
pp. 1291-1299 ◽  
Author(s):  
Daniel Sánchez-Rodríguez ◽  
Hiroki Wada ◽  
Syuhei Yamaguchi ◽  
Jordi Farjas ◽  
Hidenori Yahiro
Keyword(s):  
High Temperature ◽  
Metal Complex ◽  
Temperature Synthesis ◽  
Perovskite Type Oxide ◽  
High Temperature Synthesis ◽  
Perovskite Type

Preparation Research of CaB6 Powder by Self-Propagating High-Temperature Synthesis

2011 ◽  
Vol 284-286 ◽  
pp. 2106-2109 ◽  
Author(s):  
Yi Yong Wang ◽  
Hui Jin
Keyword(s):  
Sulfuric Acid ◽  
High Temperature ◽  
High Purity ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Vacuum Atmosphere ◽  
Reaction Atmosphere ◽  
Shs Method ◽  
Magnesium Addition

Self-propagating High-temperature Synthesis (SHS) method was adopted to synthesize powder containing CaB6, and the power was leaching by sulfuric acid. Effects of reaction atmosphere, magnesium addition, H2SO4acidity and leaching temperature on the performances of CaB6powderwas investigated, the microstructure of products were researched by SEM and XRD, the results show that the phases of products by SHS are CaB6、Mg3B2O6and Ca3B2O6, and high purity CaB6powders are obtained after the products by SHS was leaching by Sulfuric acid. The SHS conditions are the vacuum atmosphere and 30% excessive magnesium addition and the leaching conditions are 55% acidity of Sulfuric acid and 40°C leaching temperature, the perfect and uniform grain of CaB6powers are obtained at the above conditions.

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