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采用流延工艺制备了NiO-8%Y2O3/ZrO2(YSZ)阳极支撑三层一体化结构单电池,在此基础上采用浸渍工艺在多孔YSZ基体上低温制备了高活性阴极La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF).研究发现:降低电极制备温度可以得到微观形貌可控、分布均匀的纳米电极,并且避免了电极与基体间的反应:通过控制浸渍次数,制备了不同LSCF含量的电池;随着浸渍量的增加,电极的极化电阻显著下降;在800℃时,LSCF质量分数为45%的电池的功率密度高达1090 mW/cm2,同时电池稳定运行90h,表现出了很好的稳定性. 相似文献
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以氧化石墨(GO)和Pd(NO3)2为原料,通过化学还原法制备Pd纳米粒子-石墨烯(Pd/G)纳米复合材料,然后以H2PtCl6作为Pt前体,在Pd纳米粒子的表面恒电位沉积Pt,制备不同Pt负载量的Pd/G(Pt-Pd/G)电极.利用场发射扫描电镜(FE-SEM)、透射电镜(TEM)和X射线能谱仪(EDX)对材料的微观结构进行了表征和分析.结果显示石墨烯上的金属粒子分散均匀,平均粒径约7.2nm.电化学测试结果显示Pt-Pd/G电极对乙二醇电化学氧化反应具有良好的催化性能.当纳米粒子的Pt:Pd原子百分比为1:42时,其反应峰电流密度分别为Pd/G和Pt/G电极的3.0倍和2.7倍.少量的Pt沉淀可显著改进Pd/G电极的催化活性.本研究采用的修饰方法简单,修饰效果明显,可应用于其他金属纳米复合材料的异金属修饰. 相似文献
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采用传统的热分解法在不同的烧结次数制度下制备Ti/Ir-Co涂层电极,通过扫描电镜(SEM),能量分析光谱仪(EDX)和X射线衍射(XRD),循环伏安(CV)、动电位极化等测量方法考察了不同电极的表面形貌及其电化学性能。结果表明:采用先烘干三次后再烧结,重复一次后再进行烘干-烧结的工艺制备出的电极电极性能优异,且可以节约电极制备时间。 相似文献
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乙烷质子交换膜燃料电池的研究 总被引:1,自引:0,他引:1
研究了以乙烷作为燃料、全氟磺酸高分子膜(Nafion膜)作为质子交换膜、Pt或Pt-Ru作为电极催化剂主要组分、并通过掺杂Nafion膜作为电极内的离子导体构成的燃料电池电化学性能.研究了两种电极催化剂:Pt与Pt-Ru复合催化剂的制备及构成的单电池在不同温度及运行时间下的电化学性能.温度增加,电池性能变好;运行时间增加,电池性能下降,在相同的温度与运行时间下,Pt-Ru复合催化剂构成的电池比Pt催化剂构成的电池极化小.通过分析电极反应产物,探讨了乙烷电极及电池的反应机理.结构为C2H6,( Pt-Ru+膜材料复合阳极)/Nafion膜/(Pt+膜材料复合阴极),O2 的质子交换膜燃料电池,在150℃时,电池的最大输出电流和功率密度分别高达70 mA·cm-2和22 mW·cm-2. 相似文献
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以漂珠为成孔材料,以ZrO2为结合剂,采用凝胶注模的方法制备出多孔轻质材料。通过分析材料的微观形貌、物相组成、显气孔率、体积密度、抗弯强度等性能参数,研究了烧结温度1200℃~1500℃对材料性能的影响。结果得出,烧结温度达到1400℃时,漂珠外壳与氧化锆的界面结合不再明显,ZrO2颗粒由点接触扩展到面接触;烧结温度1400℃的试样中锆英石的峰最强,说明漂珠和氧化锆已烧结熔融;1400℃下制备试样的显气孔率最大(68%),体积收缩率(20.8%)最低,而抗弯强度可达7.5MPa;烧结温度控制在1400℃,可使材料处于烧结中期,保证材料的各项性能满足其应用需求。 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