Redukce wolframanových prekurzorů v plazmatu buzeném ve směsi vodíku a vhodného uhlovodíku
| Title in English | Reduction of tungsten precursors by plasma excited in hydrogen and hydrocarbons mixture |
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| Authors | |
| Year of publication | 2005 |
| Type | Article in Periodical |
| Magazine / Source | ChemZi 57.sjezd chemických společností |
| MU Faculty or unit | |
| Citation | |
| Field | Plasma physics |
| Keywords | reduction; tungsten; plasma |
| Description | Reduction of tungstates in hydrogen plasma leads to production of tungsten powder with high sintering activity. Reduction in plasma generated in the atmosphere of gaseous hydrocarbons leads to production carbides having high catalytical activity. Very interesting is though the behavior of substances originating from the reaction of plasma with cationic part of tungstates. Besides of the amonium tungstate also sodium-, calcium- and lead- tungstates were studied. Ruductions in both types of plasma have kinetic as well as thermal aspect. Influence of each type of plasma on reduction of precursors was studied from the point of view of plasma generation in plasmachemical reactors with capacitive or inductive excitation. The control of discharge dwelling at various working power was also taken into account. In the first phase of reduction bertholidic tungsten bronses are created, whose structure and stoichiometric deficiency were compared with definition of their color received by the L,a*,b* technique. In the next phase different form of cation component reduction are attained that are discussed from the thermodynamic and crystalochemical points of view. |
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