高导热少胶云母带的制备及应用研究

通过共混挤出的方法制备了高导热粉末树脂胶粘剂,在制备高导热粉末树脂胶粘剂的基础上,采用喷粉上胶技术和导热面胶制备了同时具有高透气性和高导热性的少胶云母带。结果表明:和单独使用某一尺寸的导热填料相比,采用微米、纳米和晶须混合导热填料可以更有效地提高粉末树脂胶粘剂的导热性。采用高导热少胶云母带制作的VPI板材和线棒的导热系数均有较大幅度的提高,可以有效降低线棒的温升,且介质损耗、热态介损、击穿电压和电老化寿命等电气性能与普通高透气性少胶云母带相当,可有效降低电机绝缘层温升,有望提高发电机单机容量和效率。     

大型空冷高压发电机主绝缘的导热系数与粘合剂种类、胶含量的关系

通过研究大型空冷高压发电机多胶模压主绝缘的导热系数与胶含量之间的关系,并对5440-1桐马环氧玻璃粉云母带和高强度环氧玻璃粉云母带的热传导性能进行比较.结果表明:随胶含量减小主绝缘的导热系数增大;主绝缘的胶含量基本相同时,用高强度带比桐马带压制的主绝缘的导热系数高13%～18%.     

高导热少胶云母带的研究与探讨

为了研究高导热（HTC）云母带的导热性能,对不同的高导热VPI少胶云母带的微观结构进行剖析,提出了一种高导热少胶云母带的导热性能测试方法,探讨了云母带导热系数的综合评估方法。结果表明：在现有VPI体系下,采用高导热云母带的主绝缘比采用常规云母带的主绝缘导热系数最高能提升45%,用综合导热系数λs来衡量高导热云母带的贡献更为客观全面,采用高导热云母带比常规云母带的主绝缘综合导热系数最高能提升33%。     

高导热少胶云母带的应用及其对高压电机主绝缘温升的影响

通过测试比较多种高导热少胶云母带主绝缘结构的电绝缘性能和导热性能,并进行合理的仿真计算,分析主绝缘导热系数对温升的影响。结果表明:在其他材料工艺不变的前提下,使用高导热少胶云母带可有效提高主绝缘的导热系数。采用两台电机模型计算了不同导热系数下电机主绝缘的温升值,计算结果表明,随着主绝缘导热系数的提高,温升值明显降低。     

少胶云母带在高压电机上的应用发展现状及趋势

介绍了多胶模压和液压、中胶真空压力浸渍及少胶真空压力浸渍等电机云母绝缘技术和云母纸、补强材料、胶粘剂等少胶云母带的基础材料,概述了国内外少胶云母带的技术现状及其在高压电机上的应用与选择,并展望了云母纸、补强材料、胶粘剂、纳米技术的应用、高导热少胶云母带、云母带新技术、新工艺和新设备的未来发展方向。     

导热填料对云母胶导热系数的影响研究

通过添加导热填料对云母胶进行改性,制备出具有较高导热性的胶粘剂.通过测试胶粘剂的导热系数、介电性能,电绝缘性能,系统研究了导热填料的用量、粒径、形状、晶型、种类等因素与胶粘剂导热系数的对应关系.结果表明,导热填料的最佳用量为32%(体积分数);云母胶的导热系数均随着所掺杂粉体粒径的增大而提高;相比于微孔形SiO2,球形...     

纳米复合高导热绝缘材料及其绝缘结构研究

通过异丙醇水溶液的冻融循环结合球磨工艺制备了h-BNNSs,采用微波等离子体对h-BNNSs表面进行功能化处理得到AF-BNNSs,并与甲基丙烯酸反应制备了Vi-BNNSs单体。利用此单体与纳米SiO_2杂化的乙烯基有机硅改性环氧树脂复配制备了纳米改性高导热绝缘漆;利用AF-BNNSs与有机化蒙脱土(OMMT)改性环氧树脂复合制备了一种纳米改性少胶带胶黏剂,并用该胶黏剂制备了一种纳米改性高导热少胶云母带。通过SEM、TEM、HRTEM、AFM等测试手段对h-BNNSs进行了表征,并对纳米改性高导热绝缘漆、纳米改性高导热少胶云母带及由此组合形成的绝缘结构进行了性能测试。结果表明:制备的h-BNNSs具有单层或少层的结构;由功能化h-BNNSs制备的导热绝缘材料及其组成的绝缘系统基本符合6 kV级高压电机的技术要求。     

高导热绝缘结构对永磁同步牵引电机温升影响的仿真分析

采用有限元法及有限体积法对永磁同步牵引电机内部磁场及温度场进行仿真计算,并对采用高导热环氧少胶云母带和普通云母带的绝缘体系温度场进行对比分析。结果表明:采用导热系数为0.44 W/(m·K)的高导热环氧少胶云母带的绝缘体系可以有效降低电机的内部温升,将电机线圈主绝缘的寿命提高一倍左右,保证了其运行过程中的可靠性。     

新型高导热环氧玻璃粉云母带

新型高导热环氧玻璃粉云母带(以下简称高导带)是用筛选出的填料,研制出了胶粘剂,同时选用性能优异特制粉云母纸,采用无碱玻璃布作补强材料,经适宜的工艺研制出了高导带。高导带的导热系数大于0.4W/m.K,其它性能相当于JB/T6488.3-1992云母带环氧玻璃粉云母带的标准。     

1841高导热浇注胶的研制及应用

研制了由海因环氧树脂、高导热填料、固化剂及增韧剂等合成的船用电机端部1841高导热浇注胶,分析了其产品性能、使用特点和应用工艺,并与国外同类产品进行性能对比,结果表明:1841高导热浇注胶能满足电机浇注材料的性能和工艺要求,可以替代进口产品STYCAST2850高导热浇注胶使用。     

微米氮化硼-纳米氧化铝复合环氧材料的导热与绝缘特性

环氧树脂(epoxy resin, EP)以其粘附力强、绝缘性能好等优点,在电气领域中得到广泛应用。但环氧树脂的低热导率限制其在器件中的使用,尤其在高频条件下。文中通过多巴胺改性微米氮化硼和纳米氧化铝,将制备的微纳米二元填料填充环氧树脂,研究环氧树脂复合材料的导热性能和电气绝缘性能。结果表明,质量分数22.5%BN和7.5%Al2O3环氧树脂复合材料的导热系数可以达到1.35 W/(m·K),相比于纯EP增加了812.5%,而介电损耗维持在较低水平。高频击穿实验结果展示出复合材料击穿时间明显提高,比纯环氧树脂提高了387%。该种方法制备所得的环氧树脂复合材料,具有热导率高、介电损耗低、高频击穿强度大等优点,为开发适用于高频电力电子器件的导热绝缘材料提供参考。     

PMMA-g-Al2O3填充环氧树脂纳米复合材料的制备及性能研究

以聚甲基丙烯酸甲酯(PMMA)改性nano-Al2O3为填料,制备了PMMA-g-Al2O3/EP复合材料,并对其性能进行研究。结果表明:PMMA改性Al2O3纳米粉体的加入改善了环氧树脂的导热性能、冲击强度等综合性能,其冲击强度可达到18.34 kJ/m2,热导率提高率为22.9%,体积电阻率最高为14.98×1013Ω.m,且PMMA改性纳米Al2O3填充环氧树脂的综合性能优于未改性纳米Al2O3和A151改性纳米Al2O3填充环氧树脂的性能。     

模压成型工艺制备微晶石墨/树脂双极板

以微晶石墨为导电骨料,热固性树脂为粘结剂,通过模压成型工艺制备PEMFC用微晶石墨/树脂复合材料双极板.研究了骨科粒度分布、骨料配比、树脂种类和成型条件等对双极板性能的影响.以含量为18％～20％的双酚A乙烯基树脂(P104-02)为粘结剂,粒度为200～250目的石墨粉为导电骨料,在140 ～ 145℃、15 ～ 2...     

Influence of filler on the curing and thermal aging of epoxide compounds

An experimental investigation of the filler sort and dispersity influence on inner mechanical stress in UP5–162 epoxide compound during thermal aging was carried out. It was found that the size of filler particles has a dominant influence on a value of the inner mechanical stress, while filler thermophysical properties, such as thermal conductivity and heat capacity, are more important during thermal aging. The backgrounds for maintaining of high mechanical properties of a compound are the filler particle distribution homogeneity over a compound volume, as well as a narrow dispersion distribution.     

环氧树脂/BN导热绝缘材料表面击穿特性研究

通过在环氧树脂基体中添加氮化硼（BN）颗粒以提高环氧树脂的热导率,研究了BN颗粒质量分数对脉冲电压下表面击穿试验中热导率以及放电量等的影响,得出了随着BN颗粒质量分数的增加热导率随之增加而放电量随之减小的趋势.表明,BN颗粒提高了环氧树脂的热导率,进而提高了环氧树脂复合材料的耐表面击穿性能.     

云母带粘合剂导热系数的研究

多胶云母带广泛应用于大型高压电机的主绝缘材料,其导热性直接影响到空冷电机的温升及绝缘的可靠性。采用保护热流计法导热仪、浸渍法密度计研究了目前应用比较成熟的多胶云母带粘合剂的热传导性能及其与密度的关系。结果表明:酚类固化体系的导热系数明显高于TOA体系和桐马体系;酚类固化体系中引入TOA增韧后降低了固化物的导热系数;导热系数与密度存在一定的关系,密度较大的固化物其导热系数一般也较大。     

The role of inorganic fillers in silicone rubber for outdoor insulation alumina tri-hydrate or silica

A systematic study to understand how alumina tri-hydrate (ATH) and silica fillers improve the erosion resistance of silicone rubber during dry band arcing showed that the thermal conductivity of the resulting composite material is the main criterion governing material erosion. The thermal conductivity of the composite material is dependent on the thermal conductivity, concentration, particle size, and bonding of the filler particles to the silicone matrix. In this context, either filler can be shown to perform better than the other, depending on the formulation, in the ASTM inclined plane tracking and erosion test. Therefore, the industry perception that ATH filler imports better erosion resistance than silica in silicone rubber can be misleading. The release of water of hydration from ATH appears to have a secondary effect that may be more relevant in silicone compositions having a low concentration of a filler.     

Thermal conductivity of filled silicone rubber and its relationship to erosion resistance in the inclined plane test

Silicone rubber samples having various concentrations and mean particle sizes of either alumina tri-hydrate or silica filters, prepared by room temperature and heat cured under pressure (hot pressed), are tested for erosion resistance in the ASTM D2303 inclined plane tracking and erosion test. Their corresponding thermal conductivities are determined using a transient temperature technique in which an infrared laser is employed as the heat source and a thermal imaging camera as a temperature detection device. Scanning electron microscope observations show greater filler bonding to the silicone matrix in the hot pressed samples than in the room temperature vulcanized samples leading higher thermal conductivity and increased resistance to erosion, for both ATH and silica filled samples. The correlation study shows a strong relationship between the erosion resistance and the thermal conductivity of the tested samples, highlighting the importance of an outdoor insulating material to have high thermal conductivity in order to withstand dry band arcing. The results can be used to provide guidance on filler selection for silicone rubber compounding for outdoor insulation applications.     

Electrical resistance of electroconductive plastic composite with carbon fiber filler

To obtain a new electroconductive composite, the vapor-grown carbon fiber (VGCF) has been applied to the thermoplastic resin composite as a conductive filler. The stability of electrical conductivity of the composite is investigated. The resistivity of VGCF composite is 1.7 × 10^?1 Ω·cm at room temperature which is one order smaller than that of commercial grade composites with carbon filler. The stability of electrical conductivity, under temperature change (?35 to +60°C) and for exposure tests (at room temperature and at 60°C), the VGCF composites have high degree of stability. The stability of electrical conductivity of the present composites are superior to those of conventional carbon fibers such as PAN-based, under tensile stresses and bending stresses. It is suggested that the fine conductive networks in the present composites give rise to these desirable performances.