Peculiarities of a Solid-Phase Method for the Production of Al–Fe/SiO2 and Al–Co/SiO2 Powder Catalysts
| Autor: | G. Yu. Lazarenko, S. Ya. Zhuk, V. A. Zelensky, V. S. Yusupov, B. F. Belelyubsky, V. N. Borsch, V. A. Artyukh |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Cladding (metalworking) Materials science Annealing (metallurgy) Composite number General Engineering Intermetallic Analytical chemistry Corundum Mullite 02 engineering and technology engineering.material 021001 nanoscience & nanotechnology 01 natural sciences Catalysis 0103 physical sciences engineering General Materials Science 0210 nano-technology Mass fraction |
| Zdroj: | Inorganic Materials: Applied Research. 11:709-712 |
| ISSN: | 2075-115X 2075-1133 |
| Popis: | We studied the possibility of producing powder catalysts Al–Fe/SiO2 and Al–Co/SiO2 by mixing precursor powders of Al, Fe, Co, and SiO2 in a planetary mill in gross weight ratios corresponding to the domain of existence of intermetallic compounds Al3Fe and Al3Co and annealing in vacuum at 900°C for 30 min. Annealing in air at lower temperatures (580–600°С) leads to the formation of corundum Al2O3, mullite Al6Si2O13, and silicides CoSi2, CoSi, Co2Si, FeSi2, and Fe3Si in the composite structure. The synthesized composite powders 13Al/4Co/6.5SiO2 and 13Al/4Fe/6.5SiO2 contain nonequilibrium phases. Powders without sintered masses with good flow and a fractional composition of less than 100 μm are obtained after synthesis in vacuum at 900°C for 30 min. The fractional composition of powder Fe–Al/SiO2 is characterized by a distribution of less than 50 μm (27.1%), 50–63 μm (15.3%), and 63–100 μm (57.4%); the fractional composition of powder Co-Al/SiO2 is 37.5%, 16.2%, and 46.3%, respectively. According to X-ray phase analysis, the powders synthesized at 900°С contain the phases of Fe3Al, Fe0.5Al0.5, Fe14Al86, Co2Al5, and Co27Al73; they do not contain silicides and mullites of the type Al6Si2O13. It is experimentally established that the mass fractions of the precursors Al, Fe, and Co are (Al + Fe) : SiO2 = 31 : 69 and (Al + Co) : SiO2 = 58 : 42 as a result of cladding of powder SiO2. It is concluded that the vacuum annealing mode of 900°C for 30 min does not provide the formation of intermetallic structures of the type Al13Fe4/Al3Fe and Al13Co4/Al3Co during the synthesis. We suggest optimizing the synthesis mode by using precursors of finer fractions and increasing the time of their grinding, mixing, and annealing. |
| Databáze: | OpenAIRE |
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