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研究了两种提纯天然石墨的方法:热的浓NaOH溶液和浓HNO3溶液处理。并研究测试了这两类样品及核纯石墨的循环性能,结果表明,经过处理后的天然石墨的循环性能得到很大提高,因此提高天然石墨的纯度可能是提高天然石墨循环性能的重要因素之一。 相似文献
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以对氨基苯磺酸、亚硝酸钠为原料,对天然石墨鳞片表面进行了接枝改性处理,显著提高了天然石墨鳞片的亲水性.同时将天然石墨鳞片进行煅烧处理,有效去除生产过程中附着于其表面的各种油性物质及基团.两种处理使石墨鳞片的表面具有均匀分布的亲水性,有利于水合氧化硅在石墨鳞片表面的均匀沉积,从而制备得到性能优异的新型颜料--随角异色效应颜料. 相似文献
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羧甲基纤维素包覆天然石墨性能的研究 总被引:2,自引:0,他引:2
本实验研究了羧甲基纤维素(CMC)包覆对天然石墨电化学性能的影响。通过XRD、恒电流充放电测试手段研究了不同包覆量对该复合材料结构和电化学性能的影响。结果表明:羧甲基纤维素裂解炭对天然石墨有较好的包覆作用,并且能够有效的阻止石墨在充放电过程中发生层状剥落现象,从而有效的提高复合炭材料的循环稳定性,其中5%树脂包覆量的复合材料在循环50次之后可逆容量是310.9 mAh.g-1,比天然石墨高50 mAh.g-1,并保持了首次可逆容量的97.1%。 相似文献
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本文针对天然石墨在锂离子电池中首次效率低、循环性能差的问题,开发出Al_2O_3和无定形碳复合包覆技术,制备了Al_2O_3-无定形碳包覆天然石墨。结果表明:天然石墨包覆Al_2O_3-无定形碳后,首次效率提高,满充阳极极片热稳定性提高,全电池循环和日历寿命提高。 相似文献
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溶液浸渍法提高石墨材料抗氧化性能研究 总被引:1,自引:1,他引:1
以硼酸盐、磷酸盐和复合盐三种浸渍剂对石墨材料进行了溶液浸渍法研究,研究结果表明:经溶液浸渍法处理的石墨材料氧化失重率降低,石墨抗氧化性能明显提高。溶液浸渍法是改善石墨材料抗氧化性能的有效途径。 相似文献
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利用结晶硝铵装置二段蒸发后的废热蒸汽对回收浓水进行蒸发提浓,使膜处理回收浓水温度大幅提高,并减少了回收浓水对硝铵溶液二段蒸发及真空结晶的影响,保证了结晶硝铵装置生产的正常进行。 相似文献
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ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l/3为氧气,2/3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中:A一混… 相似文献
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P. P. Budnikoff 《Journal of the American Ceramic Society》1924,7(11):817-820
The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO3 and determination of CaO by KMnO4 titration, the SO3 by Andrews method of titration of BaCrO4 has been found to give very reliable results with the least consumption of time. 相似文献
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A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases. 相似文献
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A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.
Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology. 相似文献
Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology. 相似文献
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ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES 总被引:5,自引:0,他引:5
Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log10 viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log10 viscosity as a function of soda content are smooth up to 50% Na2O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO2, 2Na2O) due to Molecular Substitution of CaO, MgO and Al2O3 for Na2O The effect is clearly brought out by plotting (from the results of English) the change of log10η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature Ta. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log10η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A12O3) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al2O3) per 100°. At the aggregation temperature the change of log10η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al2O3. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log10η due to substitution of an oxide for Na2O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na2O-CaO-SiO2. Change of Viscosity of Glass (4SiO2, 2Na2O) due to of Substitution of B2O3 for SiO2 The change of log10η (from the results of English) is plotted as a function of temperature, and also the change of log10η per per cent B2O3. The curves are more complex than for the substitution for Na2O. 相似文献
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面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。 相似文献