Chemical reactions between vanadium oxides and carbon during high energy ball milling

摘要: It has been well established that high energy ball milling of powder or mixtures can signi®cantly accelerate chemical reactions between two solid phases a phase and liquid gaseous [1±5], making it possible for the to occur at low temperatures. appears mechanical process little effect on driving force reactions, change free system as result be reasonably estimated by using available thermodynamic data [6]. is evident accelerates kinetics through repeated creation fresh interfaces reacting dynamic deformation, fracturing cold welding particles [7, 8]. If rate heat release which during and=or immediately after each collision event enough adjacent point temperature higher than ignition combustion reaction, reaction occurs milling. Many cases ignited have reported [e.g., 2, 9±11]. Reduction one vanadium oxides, V2O5, metallic Mg, Al Ti studied Yang McCormick [12]. was observed were within 10 min This shows very effective in activating oxides an active metal. In this letter, we report ®ndings from investigation into carbon activated When metal react with carbon, products CO, CO2, readily separated products. means use reducing agent eliminate need additional separate might mixed ®ne scale Four stainless steel balls (12.5 mm diameter) charge, mixture 99.7% pure V2O5 (average particle size: 50 im) 99% graphite placed hardened vial then sealed glove-box under argon atmosphere. The performed shaking speed SPEX 8000 mixer=mill. ratio weight determined according following overall 10% excessive graphite: 2V2O5 ‡ 5C! 4V‡ 5CO2