Sansan YU
,
Nianxin FU
,
Feng GAO
,
Zhitong SUI
材料科学技术（英文）
Vanadium nitrides were prepared via one step method of carbothermal reduction and nitridation of vanadium trioxide. Thermalgravimetric analysis (TGA) and X-ray diffraction were used to determine the reaction paths of vanadium carbide, namely the following sequential reaction: V2O3→V8C7 in higher temperature stage, the rule of vanadium nitride synthesized was established, and defined conditions of temperature for the production of the carbides and nitrides were determined. Vanadium oxycarbide may consist in the front process of carbothermal reduction of vanadium trioxide. In one step method for vanadium nitride by carbothermal reduction and nitridation of vanadium trioxide, the nitridation process is simultaneous with the carbothermal reduction. A one-step mechanism of the carbothermal reduction with simultaneous nitridation leaded to a lower terminal temperature in nitridation process for vanadium nitride produced, compared with that of carbothermal reduction process without nitridation. The grain size and shape of vanadium nitride were uniform, and had the shape of a cube. The one step method combined vacuum carborization and nitridation (namely two step method) into one process. It simplified the technological process and decreased the costs.
关键词:
Vanadium nitride
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null
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刘丹
,
邱文丰
,
蔡涛
,
孙娅楠
,
赵彤
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2014.01.016
以聚锆氧烷PNZ为锆源、炔丙基酚醛PN为碳源制备了一种ZrC液相陶瓷前驱体PNZ-PN,该前驱体经1 600℃热解能够转化为高度结晶的ZrC陶瓷.通过FT-IR、DSC、TGA对前驱体的固化过程及固化样的热失重行为进行了分析;通过XRD、元素分析和SEM对热解产物的晶相组成及微观形貌进行了分析.结果表明:1 200℃以下,热解产物主要是ZrO2,1 400℃时开始发生碳热还原反应出现结晶度较小的ZrC,经1 600℃热解后可完全转化为ZrC;PN的加入量会影响热解过程中陶瓷样品的ZrO2晶相及1 600℃热解产物的碳含量,通过调整PN的加入量最终可得到自由碳含量1.66％、近似纯相的ZrC陶瓷;得到的陶瓷粒子Zr、C元素分布均匀、粒径主要分布为100 ～200 nm.
关键词:
碳热还原反应
,
固化
,
热解
,
微观形貌
赵彦伟
,
周延春
,
刘宏瑞
,
李军平
,
孙文婷
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2014.04.001
综述了国内外ZrB2粉体制备技术如固相法、液相法和气相法的研究进展,详细分析了各种制备技术的特点,并展望了ZrB2粉体制备技术的发展方向.
关键词:
ZrB2
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制备技术
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硼/碳热还原法
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溶胶-凝胶法
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高频等离子体法
