共查询到19条相似文献,搜索用时 125 毫秒
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直接氮化法和碳热还原法是现代规模化制备AlN陶瓷粉体的主要方法。本文结合最新研究成果,分析了这两大类A1N粉体制备方法的优缺点,探讨了今后A1N粉体制备技术发展需要解决的关键问题。 相似文献
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电解液微弧氮化工艺简单,过去未见用其制备AlN膜的报道。采用电解液微弧氮化工艺在纯铝基片上制备了AlN陶瓷膜,利用正交试验优化工艺,研究了最优工艺制备的膜层的物相、形貌,并探讨了占空比、放电频率对膜层硬度、绝缘电阻、耐压值的影响。结果表明:正交试验优化的工艺为100mL超纯水中CO(NH2)235.0g,EDTA-2N... 相似文献
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直接氮化法制备氮化铝纳米线 总被引:1,自引:0,他引:1
在氮、氢混合气气流中(氢气10%,体积比),以铝和氯化铵混合粉体为原料,在水平管式炉中采用直接氮化法合成了氮化铝纳米线。使用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和透射电子显微镜(TEM)对纳米线的形貌和结构进行了检测与分析;研究了铝和氯化铵的比例(质量比)、反应温度、升温速度等因素对生成物的种类、形貌和氮化铝纳米线产量的影响。研究发现,所获得的AlN纳米线为单晶六方纤锌矿结构,表面不光滑且有非晶层,而AlN纳米线依照Vapor-Solid(VS,气-固)生长机制生长。获得了较为优化的制备氮化铝纳米线的工艺条件,利用VS生长机制和气相过饱和度概念对上述影响氮化铝纳米线生长的条件进行了初步的机理分析。 相似文献
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本研究采用碳热还原氮化法(CRN)合成AlN粉体。以γ-Al2O3和炭黑为原料, 采用直接发泡工艺与注凝成型相结合的方法制备出Al2O3/C泡沫, 作为合成AlN粉体的前驱体。泡沫孔隙尺寸从几十微米到几百微米, 总孔隙率56%~90%。具有通孔结构的泡沫前驱体实现了原料内部各处的均匀的固-气反应, 泡沫总孔隙率≥80%可显著提高CRN反应的速率。XRD分析结果显示: CRN过程中存在γ-Al2O3到α-Al2O3的相转变, 反应起始温度在1300℃以上, 并在1550℃反应完全。在1650℃合成得到的AlN颗粒平均粒径不超过1 µm, 氮含量为32.9wt%。 相似文献
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The isothermal nitridation of magnesium- and silicon-doped aluminium melt at 1273 K was investigated. With increasing Mg/Si ratio and decreasing oxygen content in the nitriding atmosphere, four major reaction mechanisms may be separated: (i) a passivating surface nitridation, (ii) a volume nitridation with precipitation of isolated AlN in the aluminium matrix, (iii) a volume nitridation resulting in a three-dimensionally interconnected AlN/Al composite microstructure, and (iv) a break-away nitridation with complete conversion of aluminium to AlN. The behavioural transition of the nitridation mechanism is reflected by the growth direction and the crystal morphology of AlN which change from inward (mechanisms i, ii) to outward (mechanisms iii, iv) growth of the reaction product with [0 0 0 1] as the dominating growth direction. Attempts are made to define the critical magnesium and silicon contents for the regime of controlled AlN/Al composite growth (mechanism iii) at 1273 K, in order to develop novel AlN/Al composite materials. 相似文献
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《Materials Science & Technology》2013,29(6):463-473
AbstractSeveral technologies have been reported for the synthesis of AlN. These are reviewed and described in detail. The processes are classified according to the principle of synthesis, and the AlN product characteristics for each method of synthesis are identified. Only two of the methods reported, direct nitridation and carbothermal reduction, are currently used industrially. Due to the requirement for higher quality AlN powders, several other methods are being developed. The level of development, the principle of synthesis, the raw materials used, the reaction products, and the powder characteristics of the synthesis methods are discussed. Where appropriate, environmental or safety concerns are identified. Process flowcharts for each of the technologies were developed on the basis of information available.MST/1794 相似文献
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F. Jean-Marie Haussonne 《Materials and Manufacturing Processes》1995,10(4):717-755
The different routes for the synthesis of aluminum nitride (AIN) powders are reviewed: the different industrial techniques from both the direct nitridation of aluminum metal and the carbothermal nitridation of alumina, and also other synthesis routes not industrially developed up to now. This paper presents a comprehensive presentation of the different chemical systems analyzed from the compilation of more than 70 publications and analysis of 91 patents. 相似文献
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Morph-genetic aluminum nitride/carbon composites with cablelike structure were prepared from filter paper template through the surface sol-gel process and carbothermal nitridation reaction. The resulting materials have a hierarchical structure originating from the morphology of cellulose paper. The aluminum nitride/carbon composites have the core-shell microstructure, the core is graphitic carbon, and the shell is aluminum nitride nanocoating formed by carbothermal nitridation reduction of alumina with the interfacial carbon in nitrogen atmosphere. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscope were employed to characterize the structural morphology and phase compositions of the final products. 相似文献
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Synthesis of Vanadium Nitride by a One Step Method 总被引:2,自引:0,他引:2
Sansan YU Nianxin FU Feng GAO Zhitong SUI 《材料科学技术学报》2007,23(1):43-46
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. 相似文献
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《Advanced Powder Technology》2022,33(3):103489
TiN nanoparticles were prepared at 900–1100 °C by Ni-catalysed carbothermal reduction nitridation from sol-gel using tetrabutyl titanate, citric acid monohydrate and nickel chloride hexahydrate as starting materials. The catalytic effects of nickel on the carbothermal reduction nitridation of xerogels were investigated. Ni has a crucial promoting effect on the carbothermal reduction reaction of the xerogels and visibly enhanced carbothermal reduction and nitridation reactions. The dry gel with 5% NiCl2 was added to obtain nano-TiN at 900 °C. The transmission electron microscopy analysis and Materials Studio simulation results showed that the facilitating effect of Ni on carbothermal reduction nitridation reaction was ascribed to the provision of heterogeneous nucleation sites for amorphous titania, promoting crystallisation and adsorption of N2, resulting in its smooth dissociation into highly active N atoms and consequently enhancing the carbothermal reduction nitridation. 相似文献
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