Conference on Electrical Insulation and Dielectric Phenomena
Conference on Electrical Insulation and Dielectric Phenomena
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DOI：
10.1109/tdei.2006.1714949
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发表时间：
2006
影响因子：
3.1
通讯作者：
N. Bowler;I. J. Youngs;K. P. Lymer;S. Hussain
中科院分区：
文献类型：
--
作者：
N. Bowler;I. J. Youngs;K. P. Lymer;S. Hussain
复合材料中填料颗粒上表面涂层的厚度和电导率是控制介电弛豫发生频率的关键参数。在本文中，实验结果提出了由钨涂层的玻璃微泡，嵌入在石蜡基质中形成的复合材料。钨涂层的厚度约为10 nm。有一个氧化铝的外涂层，几纳米厚，以防止氧化的钨，并防止在复合材料中形成导电通路。在10 GHz左右观察到介电弛豫。该系统的一个显著特征是弛豫频率从用固体钨填料颗粒形成的类似复合材料的计算值（约10 Hz）偏移约60倍的方式。这种转变是由于薄壳内的导体的几何限制，以及与块状钨的导电性相比，薄钨层的导电性降低。
The thickness and conductivity of a surface coating on filler particles in a composite material are critical parameters in controlling the frequency at which dielectric relaxation occurs. In this paper, experimental results are presented for composites formed from tungsten-coated glass microbubbles, embedded in a matrix of paraffin wax. The tungsten coating is of the order of 10 nm thick. There is an outer coating of alumina, a few nm thick, to prevent oxidation of the tungsten and to prevent the formation of conducting pathways in the composite. Dielectric relaxation is observed at around 10 GHz. A remarkable feature of the system is the way in which the relaxation frequency is shifted, by approximately six decades, from the calculated value for a similar composite formed with solid tungsten filler particles (≈ 10 Hz). This shift is attributed to the geometrical confinement of the conductor within a thin shell, and to the reduction in conductivity of the thin tungsten layer when compared with the conductivity of bulk tungsten.