Thermodynamic analysis on the direct preparation of metallic vanadium from NaVO_3 by molten salt electrolysis

A novel and environmentally friendly route to directly prepare metallic vanadium from NaV03 by molten salt electrolysis is proposed. The feasibility about the direct electro-reduction of NaV03 to metallic vanadi- um is analyzed based on the thermodynamic calculations and experimental verifications. The theoretical decomposition voltage of NaV03 to metallic vanadium is only 0.47 V at 800 ℃ and much lower than that of the alkali and alkali earth metal chloride salts. The value is slightly higher than that of low-valence vanadium oxides such as V203, V305 and VO. However, the low-valence vanadium oxides can he further electro-reduced to metallic vanadium thermodynamically. The thermodynamic analysis is verified by the experimental results. The direct preparation of metallic vanadium from NaV03 by molten salt electrolysis is feasible.

酸洗处理对高体积分数SiC_p/Al复合材料组织性能的影响

采用10%氢氟酸对SiC_p进行搅拌酸洗处理,用直接电热法触变成形工艺制备SiC_p增强6061Al基复合材料,研究了SiC酸洗处理对复合材料的微观组织和力学性能的影响。结果表明,经酸洗处理的增强颗粒界面平直干净,SiC_p表面产生蚀坑,比表面积增大,与铝基界面结合良好,空隙减少,且无杂质相生成。与未进行表面处理的复合材料相比,致密性和抗折强度得到显著提高。