共查询到17条相似文献,搜索用时 533 毫秒
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两步还原法制备MLCC电极用超细铜粉 总被引:1,自引:0,他引:1
为了制备MLCC电极用超细铜粉,克服CuSO4直接水合肼还原法制备的铜粉存在粒度分布不均匀、振实密度小的问题,提出了两步液相还原新工艺,即以CuSO4溶液为原料,首先采用NaOH沉淀-葡萄糖预还原制备Cu2O,然后用水合肼还原Cu2O制备超细铜粉.针对实现铜晶体的成核与长大过程的分离,研究了水合肼加入方式对铜粉性能的影响,发现较慢的水合肼滴加速度和将水合肼还原Cu2O阶段分为升温均匀成核与水合肼连续滴加长大两个过程有利于得到粒度均匀的铜粉.在最佳试验条件下制得的铜粉呈类球形,粒度分布均匀,分散性好,平均粒径为1.8μm,振实密度达4.2g/ml. 相似文献
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由于其良好的抗氧化性、热稳定性及高电导性,核壳结构铜-银包覆粉在电子浆料、导电填料等众多领域具有广阔的应用前景.总结归纳了化学还原法制备核壳结构铜-银包覆粉的研究进展,重点介绍了直接置换法和还原剂还原两种方法的制备工艺、机理及研究结果.分析表明:包覆过程中铜粉的性能、温度、搅拌速度等因素对最终包覆产品的性能有较大影响;铜粉的氧化、包覆时的水解及银盐利用率低等问题是制约核壳结构铜-银包覆粉制备的关键问题.据此提出了相应的解决措施,并对今后的研究应用方向进行了展望,为进一步深入研究奠定了基础. 相似文献
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通过单因素条件试验,找出了用葡萄糖预还原-水合肼液相还原法制备纳米铜粉的条件,再通过正交法得到最佳还原条件。试验表明:还原法得到的铜粉纯度高,结构成分更好控制,原料成本低廉,制备出的产品粒度分布窄且粒径小,还原彻底,不易产生CuO和Cu2O等杂质。 相似文献
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为研究络合剂对纳米铜粉体的制备及其催化性能的影响,分别以柠檬酸、葡萄糖为络合剂,采用溶胶-凝胶法制备纳米铜.考察了两种络合剂对制备过程以及产物结构的影响,通过催化苯氧化合成苯酚的反应考察制得的纳米铜粉的催化性能.研究表明:葡萄糖为络合剂制得的纳米铜(G-Cu)平均粒径较小(30 nm),比表面积为5.203 m2/g,在催化苯制苯酚反应时,具有较高的苯转化率(50.30%),但对苯酚的选择性较差;而柠檬酸为络合剂制得的纳米铜(C-Cu)平均粒径为55 nm,比表面积19.517 m2/g,催化苯转化率为21.95%,选择性为38.46%.此外,通过对溶胶凝胶法制备机理分析可知,在形成的胶体结构中,柠檬酸和葡萄糖中的羧基和羟基分别与铜离子进行配位. 相似文献
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E. S. Vasil’eva S. V. Kidalov V. V. Sokolov G. G. Klimov Ji Puguang 《Technical Physics Letters》2013,39(1):137-139
Nanostructural copper-detonation nanodiamond (DND) composites have been obtained by the method of spray drying. The technological process consists in spraying and drying a mixture of an aqueous copper salt solution and DND suspension, followed by thermal treatment in a reductive atmosphere. The DND content in copper powder was varied from 0.5 to 5.0 mass %. The average DND particle size in suspension was 4–6 nm. Copper-DND nanocomposite powders consist of nearly spherical particles with average size within 20–30 μm. Composition and structure of obtained materials have been studied. 相似文献
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Supin Sangsuk 《Materials Letters》2010,64(6):775-30
High surface area silver powder was prepared through Tollens process. The process involves reduction of Tollens reagent under sonication at room temperature. By gradually adding Tollens reagent into the mixture of glucose solution and sodium hydroxide solution, the silver powder forms immediately without silver mirror formation at container wall. The powders prepared through this process were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), particle size distribution and surface area. The powders were cubic crystalline silver with bimodal distribution and primary particle size of < 1 μm and surface area of 1.8 m2/g. The yield of silver powder was higher than 99%. 相似文献
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Samir K. Ghosh Asit Prakash Someswar Datta Sujit K. Roy Debabrata Basu 《Bulletin of Materials Science》2010,33(1):7-16
The effect of fuel characteristics on the processing of nano sized calcium hydroxyapatite (HA) fine powders by the solution
combustion technique is reported. Urea, glycine and glucose were used as fuels in this study. By using different combinations
of urea and glycine fuels and occasional addition of small amounts of highly water-soluble glucose, the flame temperature
(T
f) of the process as well as product characteristics could be controlled easily. The powders obtained by this modified solution
combustion technique were characterized by XRD, FTIR spectroscopy, SEM, FESEM-EDX, particle size analyser (PSD) and specific
surface area (SSA) measurements. The particle size of phase pure HA powder was found to be <20 nm in this investigation. The
effects of glucose addition with stoichiometric (μ = 1) and fuel excess (μ > 1) urea and glycine precursor batches were investigated
separately. 相似文献
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为获得更好的防护+装饰双重效果,采用不同粒径(200,400,800,1 000,1 200目)的铜金粉,利用机械镀技术在钢铁基体表面制备了铜-锌复合镀层。采用称重法分析了镀层的致密度,采用贴滤纸法检验了镀层孔隙率,采用划线划格法分析了镀层的结合强度,采用全浸腐蚀法及电化学极化法分析了镀层的耐腐蚀性能。结果表明:不同粒径铜金粉制备的镀层均覆盖完整,随铜粉粒径减小,复合镀层孔隙分布减少;随着铜粉粒径的减小,镀层的致密度逐渐增加,当铜粉粒径为1 000目时,Cu-Zn镀层的致密度已大于金属锌的密度;随着铜粉粒径的减小,镀层的结合强度增加,当铜粉粒径为200目时镀层的结合强度较差,而铜粉粒径小于400目时镀层的结合强度明显提高;随着铜粉粒径的减小,镀层的全浸腐蚀速率逐渐减小,耐腐蚀性增强。 相似文献
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采用液相还原法制备纳米铜粉和纳米铜胶体,选用十六烷基三甲基溴化铵(CTAB)或聚乙烯吡咯烷酮(PVP)为分散剂,通过X射线衍射仪、扫描电镜对纳米铜粉进行表征,通过重力沉降法测试纳米铜胶体的稳定性。结果表明:液相还原法能够制备纯度较高的纳米铜粉;CTAB浓度为0.12 mol/L时,铜粉平均粒径最小,为20 nm,CTAB浓度为0.14 mol/L且超声粉碎20 min时,纳米铜胶体最稳定;PVP浓度为6×10^-4 mol/L时,铜粉平均粒径最小,为20 nm,PVP浓度为7×10^-4 mol/L且超声粉碎20 min时,纳米铜胶体最稳定。 相似文献