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以SnO2、Ta2O5和ZnO粉为原料,通过传统陶瓷固相反应烧结法制备了压敏变阻材料,实验中ZnO含量为0~2.00%(摩尔分数),烧结温度控制在1 300~1500℃并保温2 h。研究了ZnO掺杂量和烧结温度对材料的组成、微观结构和电学性能的影响。结果表明:在温度一定条件下,随着ZnO掺杂量的增加,材料的非线性系数、压敏电压先增大后减小;在ZnO含量一定时,随着烧结温度从1 300℃升至1 450℃,材料的非线性系数、压敏电压先增大后减小。ZnO掺杂量为0.50%时,在1450℃烧结得到的样品的非线性系数最高(6.2),漏电流最小(262μA/cm2),压敏电压较高(83V/mm)。 相似文献
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《玻璃》2020,(7)
ZnO压敏陶瓷作为电压保护以及抗浪涌设备中电子元器件的核心材料,其高非线性系数,高通流容量,强浪涌吸收能力等性能研究以及低温烧结制备技术受到广泛关注。通过掺杂烧结助剂BST(Bi_2 O_3∶SiO_2∶TiO_2摩尔比为6∶4∶3),于875℃烧结制备了性能优异的ZnO压敏陶瓷。主要探究了烧结助剂的掺量对ZnO压敏陶瓷的物相组成、微观结构、体积密度以及压敏性能的影响。结果表明:BST掺杂会导致晶粒细化,有效地提高样品的致密度及压敏性能。当BST掺量摩尔分数为0.25%时,获得样品的综合性能最佳,体积密度为5.63 g/cm~3,相对密度为97.4%,非线性系数最大为38.9,电压梯度为最小值301.2 V/mm,漏电流密度为最小值0.028 A/mcm~2。 相似文献
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以SnO2、Ta2O5和ZnO粉为原料,通过传统陶瓷固相反应烧结法制备了压敏变阻材料,实验中ZnO含量为0~2.00%(摩尔分数),烧结温度控制在1300~1500℃并保温2h。研究了ZnO掺杂量和烧结温度对材料的组成、微观结构和电学性能的影响。结果表明:在温度一定条件下,随着ZnO掺杂量的增加,材料的非线性系数、压敏电压先增大后减小;在ZnO含量一定时,随着烧结温度从1300℃升至1450℃,材料的非线性系数、压敏电压先增大后减小。ZnO掺杂量为0.50%时,在1450℃烧结得到的样品的非线性系数最高(6.2),漏电流最小(262vA/cm^2),压敏电压较高(83V/mm)。 相似文献
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《中国陶瓷》2018,(11)
采用Al_2O_3掺杂,通过固相法制备Zn-Bi系压敏陶瓷,研究了不同比例Al_2O_3对ZnO陶瓷的晶粒大小、显微结构以及电性能的影响。研究表明ZBSCCMY配方中掺杂少量Al_2O_3制备得到ZnO压敏陶瓷样品的晶粒大小愈加均匀,显微结构更加致密;陶瓷物相主要由Zn O相、少量的Bi_2O_3相和微量的Zn_7Sb_2O_7尖晶石物相构成;少量Al_2O_3的掺杂改进了晶粒和晶界结构和成分,活化了晶界,降低烧制压敏陶瓷的烧结温度,优化了压敏陶瓷的非线性特性。当掺杂浓度为0.05 wt%、烧结温度为1100℃、保温2 h得到性能良好的压敏陶瓷,其压敏电位梯度可达810 V/mm,非线性系数为68,漏电流为2.4μΑ。 相似文献
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高能球磨对Pr_6O_(11)和Y_2O_3掺杂ZnO压敏电阻微观结构和电学性能的影响 总被引:1,自引:0,他引:1
利用高能球磨法制备Pr6O11、Y2O3掺杂ZnO压敏电阻,并对球磨时间对微观结构、物相组成及电学性能的影响进行了研究和分析。高能球磨有利于微观组织的均匀化和晶粒的细化,从而提高了电学性能。当球磨时间从0到10 h时,烧结后的ZnO晶粒尺寸变化从8.7到4.0μm,坯体烧结密度变化从5.40到5.62 g/cm3。最佳的制备工艺为球磨时间为7.5 h,烧结温度为1100℃,其对应的电学性能分别为:电位梯度(V1mA)是542 V/mm,漏电流(IL)是2.88μA,非线性系数(α)是47。 相似文献
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ZnO片式压敏电阻厚膜中Cr_2O_3含量的优化(英文) 总被引:1,自引:0,他引:1
研究三氧化二铬(Cr2O3)对氧化锌(ZnO)片式压敏电阻厚膜物相结构、微观结构和电性能的影响。X衍射分析表明:Cr2O3降低Bi4Ti3O12相的分解温度,并最终影响陶瓷厚膜的致密度、晶粒尺寸及电性能。当烧结温度为880℃时,Cr2O3摩尔(下同)掺量为0.3%的陶瓷厚膜能够得到良好性能:体积密度ρv=5.52g/cm3,晶界势垒Φb=0.116eV,非线性系数α=24.8。研究烧结温度与片式压敏电阻微观结构和电性能的关系,Cr2O3掺量为0.3%的片式压敏电阻在880℃烧结时,能够获得最佳电性能:压敏电压V1mA=25V,α=23.6,漏电流Il=2.8μA。该片式压敏电阻的低烧结温度和高非线性在工业生产中具有很大优势。 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