Characterization of barium titanate reinforced acrylonitrile butadiene rubber composites for flexible electronic applications: influences of barium titanate content

The aim of this study was to develop high dielectric constant flexible polymers with a highly efficient and cost‐effective approach using acrylonitrile butadiene rubber (NBR) as the polymer matrix and barium titanate (BT) as the high dielectric constant filler. The BT powder was synthesized with a solid‐state reaction and was characterized using a particle size analyzer, XRD, SEM and Fourier transform infrared spectroscopy. NBR/BT composites were fabricated using an internal mixer with various BT loadings up to 160 phr. The influence of BT loading on the cure characteristics and mechanical, dynamic mechanical, thermal, dielectric and morphological properties was determined. The incorporation of BT in the NBR matrix shortened scorch time and increased delta torque. The mechanical properties, thermal stability and dielectric constant were greatly improved and increased with BT loading. The results suggest that the reinforcement effect was achieved due to strong hydrogen bonding or polar–polar interactions between NBR matrix and BT filler. This is further corroborated by the good dispersion of BT filler in the NBR matrix observed with SEM imaging. These findings can be applied to produce high‐performance dielectric elastomers. © 2020 Society of Industrial Chemistry     

软锰矿氧化硫化钡制高纯碳酸锰和氢氧化钡工艺研究

软锰矿同硫化钡溶液在较低温度下进行氧化还原反应，当硫化钡含量控制在26-75g／L范围内，软锰矿与硫化钡的物质的量比为2．5-3，反应时间50-60min，软锰矿被硫化钡还原为MnO，其还原率可达93．5％以上；还原后的锰用硫酸浸取，溶液经除杂后，与碳酸铵反应而制成高纯碳酸锰。硫化钡则被氧化为氢氧化钡，经蒸发、结晶而制得入水氢氧化钡，其回收利用率高速95％。     

Structural properties of inorganic materials: tungsten bronze SBN ceramics

Rare-earth doped strontium barium niobates were synthesized using usual ceramic technique. The dopants are La, Ce, Gd, Sm and Nd. The materials were characterized by XRD and density measurements. The grain sizes were determined from SEM analysis. Lattice parameters changed uniformly with rare-earth dopants in unfilled structures. Density measurements and SEM analysis confirmed only minute changes in the densities of the ceramics.     

Mechanism for the Peritectic Reaction and Growth of Aligned Grains in YBa2Cu3O6+x

It is experimentally observed that the peritectic reaction, 211 + liquid → 123, can be driven essentially to completion in 1 h at an undercooling of only ∽30°C. The kinetic data, together with the observed microstructures, are inconsistent with the normal mechanism of the peritectic reaction. It is proposed that the mechanism of the reaction involves dissolution of 211 particles into the liquid and precipitation of solid 123. The aligned grain structure is explained through sympathetic nucleation of new 123 grains on existing grains.     

Effect of the Liquid-Phase Characteristic on the Microstructures and Dielectric Properties of Donor- (Niobium) and Acceptor- (Magnesium) Doped Barium Titanate

Changes in the microstructure and dielectric properties with the variation of the donor/acceptor ratio in BaTiO₃ ceramics were investigated. In donor-rich specimens, a liquid that appeared during sintering did not penetrate into grain boundaries. However, in the acceptor-rich specimens, the grains were separated by a liquid film during sintering. The much higher mobility of the liquid film than that of the grain boundaries was suggested to cause extensive grain growth in acceptor-rich BaTiO₃. The macroscopic homogenization of dopants because of grain growth in acceptor-rich specimens resulted in changes in the dielectric properties.     

60Si2Mn(A)弹簧钢的脱氧工艺

为了提高60Si2Mn(A)弹簧钢的质量,在LF精炼中进行了不同脱氧工艺的脱氧试验。结果表明:采用铝预脱氧、钡合金终脱氧及夹杂物变性脱氧工艺可使弹簧钢的氧含量降低到15×10-6以下,氧化物夹杂中Al2O3的比例小于40%。     

X-射线荧光增量法测定硅铁合金中的Ca、Ba

介绍了X-射线荧光增量法同时测定硅铁合金中的Ca、Ba，探讨了基体效应校正、扩展曲线的应用范围，方法准确度和精度高。     

贵州天柱重晶石回转窑还原焙烧生产工艺研究

中国重晶石资源储量丰富,为科学合理利用,避免重晶石开发过程中浪费,采用?3.2 m×60 m回转窑还原焙烧处理贵州天柱重晶石,考察了焙烧温度、抛煤对重晶石还原效果的影响。结果表明,当高温区温度为1 050~1 200 ℃、窑尾温度为500~600 ℃、窑头温度为750~850 ℃、回转窑转速为0.20~0.40 r/min、处理量为15~20 t/h、吨矿耗煤为191.64 kg时,获得粗钡中硫化钡质量分数为70.5%、粗钡浸出率为91.3%的良好指标,焙烧矿石及浸出考核指标均合格,对合理利用中国储量巨大的重晶石矿资源具有重要的现实意义。     

Dependence of dielectric properties on BT particle size in EP/BT composites

The polymer-ceramic composites of epoxy resin (EP) and barium titanate (BT) were prepared.BT powders of different BT particle sizes from 100 nm to 1 μm were used in the preparation.The dielectric properties, such as dielectric constant, dielectric loss and electrical breakdown strength, of the EP/BT composites were studied.The morphology of the composites was characterized by the means of scanning electron microscopy (SEM).The results show that the dielectric constant of the composites is much higher than the epoxy matrix at frequency range from 1 kHz to 10 MHz, and it is also obviously dependent on the size of BT particles.The electrical breakdown strength of the composites decreases with the increase of the BT content.The dependence of electrical breakdown strength on BT particle sizes was also discussed.     

Combined XPS and TPR study of sulfur removal from a Pt/BaO/Al2O3 NO x storage reduction catalyst

Pt/Al₂O₃ and Pt/BaO/Al₂O₃ catalysts (1 wt% Pt, 10 wt%BaO) were sulfated under conditions simulating a real NSR catalyst operation. Comparative TPR and XPS studies of sulfur removal from Pt/Al₂O₃ and Pt/BaO/Al₂O₃ catalysts indicate that the sulfur removal from Al₂O₃ surface precedes reductive decomposition of BaSO₄ (250–400 °C). Barium sulfate decomposition started with further increase in desulfation temperature at the point of surface atomic ratio Ba:S = 1 (~450^o). Simultaneously, an intensive formation of sulfide species on the catalyst surface was observed. Thermodynamic analysis of the desulfation process allows us to hypothesize that barium sulfide formation may hinder sulfur removal under reducing conditions.