Combustion synthesis of calcium aluminates
TL;DR: In this paper, a straightforward combustion synthesis technique to prepare submicron calcium aluminates using the corresponding metal nitrates-urea mixtures, at low temperature and short reaction times, was discussed.
About: This article is published in Materials Research Bulletin.The article was published on 1996-10-01. It has received 221 citations till now. The article focuses on the topics: Calcium aluminates & Calcium aluminate cements.
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TL;DR: Nanocrystalline calcium phosphate based bioceramics are the new rage in biomaterials research as discussed by the authors, which is mainly concentrated on bioactive and bioresorbable ceramics, i.e., hydroxyapatite, bioactive glasses, tricalcium phosphates and biphasic calcium phosphates.
482 citations
TL;DR: In this article, a series of CuO-ZnO−ZrO2 (CZZ) catalysts were synthesized by a glycine-nitrate combustion method and characterized by XRD, BET, N2O chemisorption, SEM and TPR techniques.
277 citations
TL;DR: In this article, NH 4 NO 3 was used as an additive to boost the specific surface area of the catalysts, and the results showed that the resulting materials behave practically as the perovskites obtained by the “citrates” method.
232 citations
01 Jan 2002
TL;DR: In this paper, NH 4 NO 3 was used as an additive to boost the specific surface area of the catalysts, and the results showed that the resulting materials behave practically as the perovskites obtained by the “citrates” method.
Abstract: Combustion synthesis has been applied to LaMnO 3 production with a view to boosting its activity towards natural gas combustion by enhancing its specific surface area. With a highly exothermic and self-sustaining reaction, this oxide can be quickly prepared from an aqueous solution of metal nitrates (oxidisers) and urea (fuel). The favourable conditions for LaMnO 3 formation were sought: only fuel-rich mixtures are effective, but carbonaceous deposits are formed when too much urea is used. In the field of operating conditions in which the combustion synthesis reaction takes place, the specific surface areas were not dramatically higher than those obtained with traditional methods; moreover, even short thermal treatments have been found to rapidly deactivate the catalysts by rapid sintering. With a view to tackling these problems, NH 4 NO 3 was chosen as an additive for its low costs, highly exothermic decomposition and because it generates gaseous products only, without altering the proportion of the other elements in the catalysts. With ammonium nitrate, specific area was enhanced from 4 m 2 /g up to about 20 m 2 /g. A short thermal treatment at 900 °C partially deactivates also the NH 4 NO 3 -derived catalysts. It was found that NH 4 NO 3 -boosted mixtures produce materials whose activity, after a similar thermal treatment, behave practically as the perovskites obtained by the “citrates” method. Combustion synthesis is though rather cheap—in terms of reactants employed—and quick, given that the process requires few minutes at low temperature without successive calcination. However, the main drawback of this method is that hazardous or polluting compounds are emitted during the synthesis (mainly NH 3 or NO x ). The MgO introduction, which should act both as a structural promoter and as a sulphur poisoning limiting agent, has proved to be harmful: since MgO does not physically interpose between perovskite grains, it does not offer resistance to deactivation induced by high temperatures.
204 citations
TL;DR: In this article, single-phase nanocrystalline CoAl 2 O 4 spinel powder with a high surface area has been directly prepared by an auto-ignited gel combustion process using citric acid as a reductant/fuel and metal nitrates as oxidants.
Abstract: Single-phase nanocrystalline CoAl 2 O 4 spinel powder with a high surface area has been directly prepared by an auto-ignited gel combustion process using citric acid as a reductant/fuel and metal nitrates as oxidants. The molar ratio of fuel to nitrates in the redox mixture and the subsequent calcination upon the burnt powder were found to have a significant influence on the characteristics of the as-synthesized CoAl 2 O 4 crystallites. By controlling the CA/NO 3 − ratio and calcination temperature, homogeneous crystalline CoAl 2 O 4 powders with different particle sizes from 9 to 110 nm have been obtained. Gel formation, combustion behavior, microstructures and properties of the powders were characterized using DTA/TGA, FT-IR, XRD, FESEM, TEM, BET and UV/vis/IR.
179 citations
References
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Book•
01 Jan 1978
TL;DR: This encyclopedic work includes authoritative coverage of atomic and molecular structure, organic chemistry (revised), inorganic, analytical, and electro- chemistry, mathematics as applied to chemistry, and more.
Abstract: Lange's Handbook has served as a leading source of reliable chemical information and data for chemists, engineers, and other technical specialists since l934. This encyclopedic work includes authoritative coverage of atomic and molecular structure, organic chemistry (revised), inorganic, analytical, and electro- chemistry, mathematics as applied to chemistry, and more. It also includes nomenclature consistent with recommendations of the IUPAC Commission rules.
7,848 citations
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01 Jan 1934
TL;DR: The Chemical Engineers handbook as mentioned in this paper, Chemical engineers handbook, Chemical engineer handbook, Chemical engineers Handbook, Chemical Engineering handbook and Chemical Engineers Handbook, 2007.2.1.
Abstract: Chemical engineers handbook , Chemical engineers handbook , کتابخانه دیجیتالی دانشگاه علوم پزشکی و خدمات درمانی شهید بهشتی
2,611 citations
TL;DR: In this paper, a simple method of calculating the elemental stoichiometric coefficient, φe has been developed, which can easily be applied to multicomponent fuel-oxidizer compositions.
1,062 citations
TL;DR: In this article, the effect of fuel content, powder packing, and surface heat loss has been investigated in terms of the maximum reaction temperature and reaction period, phase formation, and particle size and morphology.
Abstract: An important, rather novel procedure for the synthesis of submicron crystalline multicomponent oxide ceramic powders has been studied. The synthesis of CuFe2O4 powder, a ferrite material, has been used as a model system for understanding the synthesis process. The effect of the fuel content, powder packing, and surface heat loss has been investigated in terms of the maximum reaction temperature and reaction period, phase formation, and particle size and morphology. It has been shown that the maximum temperature and reaction period can be tailored to produce different phases. The submicron features of the synthesized powders are indicated by the large surface area values obtained from BET measurement.
164 citations