橡胶/碳纤维层压复合导电发热板的电学性能研究

研究了橡胶／碳纤维层压复合导电面状发热板的电学性能。结果表明,硫化过程对导电发热板的电阻有直接影响,不同规格导电发热板的电阻下降率不同;导电发热板具有较发的热循环稳定性,数次热循环后,室温电阻可保持恒定;其伏－安特性、表面温度－功率密度均呈现良好的线性关系;在长期通电使用下,能保持其功率的稳定性。     

模具固化成型法弹性电极的制作

为了解决用于机器人触觉感知的柔弹性电极导电稳定性差、柔弹性不够、易被磨损破坏等问题,基于银纳米线及聚二甲基硅氧烷采用模具固化成型方法设计制作了长条形弹性电极,并进行了拉伸试验。结果表明:拉伸后的电阻增量为电阻初始值的380%,且多次拉伸后,电阻波动值都很小,这种弹性电极保持了良好的导电性和导电稳定性,可以应用于拉伸、弯曲、扭转等多种复杂的应用场合。     

影响刚性电引火元件桥丝焊接稳定性的分析

刚性电引火元件（如图1）具有电阻均一性好、电参数偏差小、引火药头结构稳定等特点,逐步替代了弹性电引火元件用于工业电雷管的生产。刚性电引火元件质量要达到要求,涉及很多方面,其中桥丝电阻的均一、稳定性是核心因素之一,下面重点分析了影响桥丝焊接质量稳定性的因素。     

导电胶的研究进展

介绍了导电胶的导电机理,分析了提高导电胶导电性能、接触电阻稳定性以及力学性能的途径.     

基于波波夫超稳定性在永磁同步电机控制系统中的应用

针对永磁同步电机无速度传感器控制系统进行设计,选择定子电流为状态变量,利用波波夫超稳定性(Popov)理论确定转子转速、转子电阻和控制绕组电阻的自适应律,然后将由观测器得到的定子电流直接用于永磁同步电机控制中。根据模型参考自适应(MRAS)的稳定性原理,得到估计速度的自适应规律,而超稳定性保证了永磁同步电机控制系统和速度的渐进收敛性。理论分析表明,所探究的方法保证了速度辨识算法的全局渐进稳定性,经过MATLAB/Simulink环境下的仿真,证明了这种方法的有效性。     

滚镀光亮锡工艺

介绍了特种电器元件电阻帽滚镀酸性光亮锡工艺。从工艺配方、镀液配制方法、工艺流程、镀液稳定性及维护方法几个方面进行了实质性的探讨,根据电阻帽的型号,采用不同容积的滚桶进行滚镀,阐述了一些实用经验。     

氮化硼改善BaTiO_3基高温热敏陶瓷耐压特性的研究

研究了掺杂BN对改善高温PTC热敏陶瓷耐压特性的影响。实验结果表明,BN的加入促进了产品在达到最大电阻后电阻的稳定性,大幅提高了PTC陶瓷的耐电压强度,同时降低了其烧成温度,弱化了保温时间对敏感陶瓷常温电阻率的影响,提高了PTC的性能。     

辐射对PVDF/氟橡胶/CB复合物PTC特性的影响

研究了电子束辐照对聚偏氟乙烯／氟橡胶／炉法炭黑导电复合材料正温度系数复演性及电阻稳定性的影响规律。结果表明,随辐射剂量提高,凝胶含量上升,ＰＴＣ复演性提高。由该体系制得的自限温伴热带的长期使用工作温度及功率稳定性提高,通断电循环试验的功率及电阻变化较小,可用于制备１３５℃高温级处限温伴热带。     

医用设备用各向同性导电胶的研究

在粘接固化过程中,在界面处出现原子能级现象和器件老化过程是文章的主要焦点之一.讨论了组装过程的基本原子和分子水平机理以及材料化学对电阻稳定性的影响.该机制包括在粘合剂固化过程中导电路径形成在粘合剂和金垫界面上以及界面在老化过程中是如何演变的.还讨论了可能影响电阻不稳定性的粘合剂配方中的成分,以及稳定电阻的溶液空间.     

高分子分散剂在抗静电涂料中的应用研究

研究了分散剂种类及其用量对自制抗静电涂料的粘度、分散稳定性及涂层电阻的影响，确定了合适的分散剂及其最佳用量。     

Morphology,Thermal Stability,and Electrical Conductivity of Polymer Nanocomposites of Isotactic Polypropylene/Multi-Walled Carbon Nanotubes

Molecular weight of isotactic polypropylene (iPP) and concentration of multi-walled carbon nanotubes (MWCNT) effects on the morphology, thermal stability, and electrical conductivity for iPP/MWCNT nanocomposites were evaluated. Nanocomposites were prepared by solution mixing followed by non-isothermal crystallization from the melt. The samples were characterized by different physical-chemical techniques. Electrical conductivity was obtained from electrical resistance measured using a source meter. It was determined that the morphology of the nanocomposites shows a change from spherulitic to fibrillar to undefined depending on the molecular weight of iPP and concentration of MWCNT. Morphology was correlated with thermal stability and electrical conductivity.     

CO<Subscript>2</Subscript>-laser treatment of indium tin oxide nanoparticle coatings on flexible polyethyleneterephthalate substrates

A CO₂-laser treatment was used to improve the electrical conductivity of coatings of indium tin oxide (ITO) nanoparticles on flexible polyethyleneterephthalate (PET) substrates. The electrical conductivity and the transparency of CO₂-laser-treated ITO nanoparticle coatings were characterized with regard to the application as transparent electrodes. Furthermore, the stability of the electrical conductivity under oscillatory bending was investigated. A specific resistance of 0.12 Ω cm is obtained by CO₂-laser treatment without thermally damaging the PET film. The improvement of the electrical conductivity can be explained by a slight sinter neck formation. For a film thickness of 3 μm, a sheet resistance of 400 Ω/□ and a transmission in the visible range of 80% were achieved. The stability of the electrical conductivity of CO₂-laser-treated ITO nanoparticle coatings under bending was investigated using a specially constructed device for the application of various oscillatory bending loads. For a bending radius of 10 mm, the sheet resistance does not exceed 1000 Ω/□ after 300 bending cycles. Compared to commercial sputtered ITO coatings, CO₂-laser-treated ITO nanoparticle coatings show a significant higher stability under oscillatory bending.     

Studies on the properties of glass fiber reinforced epoxy composites of DGEBA / epoxidized polyhydric alcohols with or without fortifier

Differential scanning calorimetry (DSC) technique was used to study the curing reaction of diglycidyl ether of bisphenol A (DGEBA) resin and different di- and trifunctional polyhydric alcohols with phthalic anhydride as curing agent and triethylamine as catalyst with or without fortifier. The thermal stability of the cured products was also studied by thermogravimetric analysis (TGA). Using these data, different glass fiber reinforced epoxy composites were fabricated and their mechanical and electrical properties and their resistance to chemicals were studied as well. Activation energies of curing reactions range within 75.1 to 88.3 kJ mol^?1. The cured products have good thermal stability; the composites have good mechanical strength, electrical insulation properties and chemical resistance. 36 to 53% improvement in flexural strength has been observed when fortifier was added to the DGEBA-diluent systems.     

Corrosion behavior in simulated environments of ITZO films prepared by two targets co-sputtering

Indium tin zirconium oxide (ITZO) films were deposited by a co-sputtering technique with ITO and zirconium targets. The stability and corrosion behavior of films in simulated environments were studied on account of microstructure and optical–electrical properties. The results show that ITZO films possess a better crystalline structure and optical–electrical properties. Zirconium-doping changes the preferred orientation of ITO films, and ITZO films under the optimum parameters have sheet resistance of 10 Ω/sq and transmittance of above 85%. According to the polarization measurements and the relative resistance change of the films in simulated environments such as acidic climate, oceanic climate and industrial climate, the doping films show better chemical and thermal stabilities than ITO films. Besides the influence of crystal structure, the better stability of zirconium oxide can improve the chemical and thermal stabilities. ITZO films have better electrical stability and chemical antcaustic properties, and the films could find more extensive applications.     

Enhanced electrical conductivities of N-doped carbon nanotubes by controlled heat treatment

The thermal stability of nitrogen (N) functionalities on the sidewalls of N-doped multi-walled carbon nanotubes was investigated at temperatures ranging between 1000 °C and 2000 °C. The structural stability of the doped tubes was then correlated with the electrical conductivity both at the bulk and at the individual tube levels. When as-grown tubes were thermally treated at 1000 °C, we observed a very significant decrease in the electrical resistance of the individual nanotubes, from 54 kΩ to 0.5 kΩ, which is attributed to a low N doping level (e.g. 0.78 at% N). We noted that pyridine-type N was first decomposed whereas the substitutional N was stable up to 1500 °C. For nanotubes heat treated to 1800 °C and 2000 °C, the tubes exhibited an improved degree of crystallinity which was confirmed by both the low R value (I(D)/I(G)) in the Raman spectra and the presence of straight graphitic planes observed in TEM images. However, N atoms were not detected in these tubes and caused an increase in their electrical resistivity and resistance. These partially annealed doped tubes with enhanced electrical conductivities could be used in the fabrication of robust and electrically conducting composites, and these results could be extrapolated to N-doped graphene and other nanocarbons.     

In situ evaluation of container corrosion in sodium — sulphur batteries

Recent improvements in container materials for Na/S cells (central sodium type) have led to greatly enhanced cell life and performance. Although problems with rapidly decreasing capacity are no longer observed, cells appear to exhibit a slowly increasing resistance with time. This paper describes anin situ technique for assessing the electrical stability of various container materials and determining the extent that corrosion processes influence cell resistance changes. Potentials within the sulphur electrodes of operating cells were measured over prolonged cycling times. Results indicate that chromized steel possesses excellent electrical stability compared to 347 stainless steel and that container corrosion accounts for only a fraction of the increase in total cell resistance.     

Synthesis and curing kinetics of colored epoxy resin containing azo moiety

Colored epoxy resin containing azo moiety was synthesized by reaction between epichlorohydrin and bis-azodiol, which was synthesized by coupling bisphenol-A with aromatic amine. Colored epoxy resin was characterized by epoxy equivalent weight, IR spectra, Viscosity and UV visible spectroscopy. The curing of colored epoxy resin and DGEBA were characterized by differential scanning calorimetry (DSC). The thermal stability of cured products was characterized by thermogr avimetric analysis (TGA). The cured products have good thermal stability. Several glass fiber epoxy composites were fabricated and their mechanical properties, electrical properties and chemical resistance were studied.     

Adhesion Improvement of Powder Coating on Medium Density Fibreboard (MDF) by Thermal Pre-treatment

In the powder coating of non-conventional substrates such as engineered wood, natural fibre composites or synthetic polymers, several technological problems must be resolved which result from the substantial differences between such coating substrates and metallic ones. Unlike metals, non-conventional carrier materials show low temperature stability, much rougher and more irregular surface texture, large dependence of their dimensional stability on the moisture content of the surrounding environment and significantly less electrical conductivity. Hence, when powder technology is transferred from coating metals to coating fiberboards, for example, the surfaces of the boards need to be engineered in order to provide ideal adhesion for the coating layer. One major problem is the lack of electrical conductivity. Since the powder coatings are preferably applied using electrostatic spraying equipment, sufficient electrical conductivity of the surface is a major requirement and the correct moisture content plays an important role as well. In the present study, a pre-heating process was used to improve the powder application during powder coating of medium density fibreboards (MDFs). Electrical resistance, treatment temperature and moisture content were systematically studied to better understand the complex physical mechanisms leading to an improvement in powder application by such a pre-heating process. To this end, a new sophisticated procedure was developed to measure the electrical resistance (surface and core resistance) during pre-heating. The results show, that the electrical resistance of MDF is influenced by board temperature and moisture content. Moreover, it is confirmed that pre-heating proves to be an efficient method to improve the powder application onto non-conventional substrates.