碳热还原法制备V_8C_7粉体
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摘要
以偏钒酸铵、二氧化钛及石墨为原料,采用碳热还原法,成功制备V_8C_7粉体;采用X射线衍射物相分析、热重-差热分析、扫描电镜形貌观察以及粒度分析等方法研究偏钒酸铵碳热还原制备V_8C_7的还原过程,优化了配碳系数。结果表明:低温一次还原以偏钒酸铵脱氨脱水分解反应以及低价钒氧化物的形成为主;高温二次还原以钒氧化物向非化学计量VC_x的转化为主;随着配碳系数的增加,反应产物VC_x的晶格常数不断增大;当反应温度为1 500℃、配碳系数为0.9时可获得钒原子和碳原子有序排列的单相V_8C_7,粒径约为2.7μm。
V_8C_7powders were prepared by the carbothermal reduction method taking ammonium metavanadate, titanium dioxide and graphite as raw materials. The reduction process of ammonium metavanadate was investigated with combination of XRD, TG-DSC, SEM and particle analysis methods and the carbon coefficient was optimized. Results show that in the period of once low-temperature reduction, major reactions are decomposition of ammonium and formation of vanadium sub-oxides. During the second high-temperature vacuum reduction, the vanadium oxides convert to the reduction products of non-stoichiometry VC_x. The lattice constants of VC_xincrease with carbon coefficient increasing. When the reaction temperature is 1 500 ℃ and the carbon coefficient is 0.9, single phase V_8C_7 is obtained with orderly arrangement of vanadium atoms and carbon atoms. The grain size is about 2.7 μm.
V_8C_7powders were prepared by the carbothermal reduction method taking ammonium metavanadate, titanium dioxide and graphite as raw materials. The reduction process of ammonium metavanadate was investigated with combination of XRD, TG-DSC, SEM and particle analysis methods and the carbon coefficient was optimized. Results show that in the period of once low-temperature reduction, major reactions are decomposition of ammonium and formation of vanadium sub-oxides. During the second high-temperature vacuum reduction, the vanadium oxides convert to the reduction products of non-stoichiometry VC_x. The lattice constants of VC_xincrease with carbon coefficient increasing. When the reaction temperature is 1 500 ℃ and the carbon coefficient is 0.9, single phase V_8C_7 is obtained with orderly arrangement of vanadium atoms and carbon atoms. The grain size is about 2.7 μm.
引文
[1]吴恩熙,颜练武,钱崇梁,等.纳米V8C7粉末的制备[J].中南大学学报(自然科学版),2005,36(5):771-775.
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[8]姜中涛,李力,陈巧旺,等.常压下碳热还原制备碳化钒(V8C7)粉末的研究[J].硬质合金,2011,28(5):294-299.
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[10]姜中涛,刘颖,李力,等.真空热处理对碳化钒粉末制备的影响[J].材料热处理学报,2012,33(3):6-10.
[11]姜中涛,刘颖,陈巧旺,等.原料粉末对制备碳化钒的影响[J].粉末冶金工业,2012,22(2):18-21.
[12]LI Z R,CAO Z Q,FANG M X.Study on thermodynamic principle of preparation of VC by carbon-heat reducing[J].Advanced Materials Research,2011,28(2):1253-1258.
[13]CAO Z Q,FANG M X,LI Z R.The research of carbonization and deoxidizing V2O5at low temperature[J].Advanced Materials Research,2012,32(2):344-349.
[14]颜练武.纳米V8C7粉末的结构、性能和应用研究[D].长沙:中南大学,2008.
[15]颜练武.V8C7有序-无序相变及衍射消光规律的研究[J].硬质合金,2013,30(5):249-255.
[2]罗奕兵,颜练武.碳化钒有序-无序相变的热力学研究[J].硬质合金,2015,32(2):79-82.
[3]胡文萌,赵志伟,陈飞晓,等.纳米碳化钒粉末制备的研究现状[J].粉末冶金工业,2015,25(6):62-65
[4]徐本平.钒钛物料中钒钛化学物相分析现状及最新进展[J].中国无机分析化学,2014,4(2):18-23
[5]张雪峰,陈敏,肖玄,等.碳热还原法制备碳化钒钛的过程研究[J].中国粉体技术,2015,21(3):25-28
[6]姜中涛,刘颖,陈巧旺,等.V2O5碳热还原合成碳化钒粉末的反应过程[J].粉末冶金技术,2012,30(1):40-45.
[7]望军,吕凌,孙晓燕,等.VC对微米级Ti(CN)基金属陶瓷微观结构和力学性能的影响[J].工具技术,2008,42(8):14-16.
[8]姜中涛,李力,陈巧旺,等.常压下碳热还原制备碳化钒(V8C7)粉末的研究[J].硬质合金,2011,28(5):294-299.
[9]姜中涛,叶金文,刘颖,等.碳热还原法制备V8C7粉末的研究[J].功能材料,2009,40(5):820-822.
[10]姜中涛,刘颖,李力,等.真空热处理对碳化钒粉末制备的影响[J].材料热处理学报,2012,33(3):6-10.
[11]姜中涛,刘颖,陈巧旺,等.原料粉末对制备碳化钒的影响[J].粉末冶金工业,2012,22(2):18-21.
[12]LI Z R,CAO Z Q,FANG M X.Study on thermodynamic principle of preparation of VC by carbon-heat reducing[J].Advanced Materials Research,2011,28(2):1253-1258.
[13]CAO Z Q,FANG M X,LI Z R.The research of carbonization and deoxidizing V2O5at low temperature[J].Advanced Materials Research,2012,32(2):344-349.
[14]颜练武.纳米V8C7粉末的结构、性能和应用研究[D].长沙:中南大学,2008.
[15]颜练武.V8C7有序-无序相变及衍射消光规律的研究[J].硬质合金,2013,30(5):249-255.