β-Sialon based composites were successfully prepared from fly ash and carbon black under nitrogen atmosphere by carbothermal reduction-nitridation process. Effects of heating temperature and raw materials composition...β-Sialon based composites were successfully prepared from fly ash and carbon black under nitrogen atmosphere by carbothermal reduction-nitridation process. Effects of heating temperature and raw materials composition on synthesis process were investigated, and the formation process of the composites was also discussed. The phase composition and microstructure of the composites were characterized by X-ray diffraction and scanning electronic microscopy. The results show that increasing heating temperature or mass ratio of carbon black to fly ash can promote the formation of β-Sialon. The β-Sialon based composites can be synthesized at 1723 K for 6 h while heating the sample with mass ratio of carbon black to fly ash of 0.56. The as-received β-Sialon in the composites exists as granular with an average particle size of 2-3 μm. The preparation process of β-Sialon based composites includes the formation of O′-Sialon, X-Sialon and β-Sialon as well as the conversion processes of O′-Sialon and X-Sialon to β-Sialon.展开更多
Experimental and numerical studies were carried out for the behavior of hydrogen in a three-phase electro- slag furnace using double electrode series technique during electroslag remelting （ESR） process. The effect ...Experimental and numerical studies were carried out for the behavior of hydrogen in a three-phase electro- slag furnace using double electrode series technique during electroslag remelting （ESR） process. The effect of water vapor content of furnace gas on the hydrogen content of ingots was studied through the ＂gas-slag-metal＂ osmosis ex- periment. Based on the experimental results, a mathematical model was set up for the behavior of hydrogen pick-up during ESR process. Then the flow of furnace gas during ESR process was studied through a commercial code FLU- ENT, and the relationship between the water vapor content of furnace gas and argon gas flux in practical production was derived. Finally, the desired reasonable argon gas flow for controlling the hydrogen content of ingots below 2 × 10-6 in practice was obtained.展开更多
基金Project (51074038) supported by the National Natural Science Foundation of ChinaProject (N100302002) supported by the Fundamental Research Funds for the Central Universities, China
文摘β-Sialon based composites were successfully prepared from fly ash and carbon black under nitrogen atmosphere by carbothermal reduction-nitridation process. Effects of heating temperature and raw materials composition on synthesis process were investigated, and the formation process of the composites was also discussed. The phase composition and microstructure of the composites were characterized by X-ray diffraction and scanning electronic microscopy. The results show that increasing heating temperature or mass ratio of carbon black to fly ash can promote the formation of β-Sialon. The β-Sialon based composites can be synthesized at 1723 K for 6 h while heating the sample with mass ratio of carbon black to fly ash of 0.56. The as-received β-Sialon in the composites exists as granular with an average particle size of 2-3 μm. The preparation process of β-Sialon based composites includes the formation of O′-Sialon, X-Sialon and β-Sialon as well as the conversion processes of O′-Sialon and X-Sialon to β-Sialon.
基金Item Sponsored by National Natural Science Foundation of China(51274057)Key Projects in National Science and Technology Pillar Program of China(2011BAE13B03)National High-Tech Research and Development Program of China(2013AA03092,2012AA03A508)
文摘Experimental and numerical studies were carried out for the behavior of hydrogen in a three-phase electro- slag furnace using double electrode series technique during electroslag remelting （ESR） process. The effect of water vapor content of furnace gas on the hydrogen content of ingots was studied through the ＂gas-slag-metal＂ osmosis ex- periment. Based on the experimental results, a mathematical model was set up for the behavior of hydrogen pick-up during ESR process. Then the flow of furnace gas during ESR process was studied through a commercial code FLU- ENT, and the relationship between the water vapor content of furnace gas and argon gas flux in practical production was derived. Finally, the desired reasonable argon gas flow for controlling the hydrogen content of ingots below 2 × 10-6 in practice was obtained.
