Degradation electrical

Eouling and corrosion on insulator surfaces leading to electrical degradation... 

Dissado, L. A. Fothergill, J. P. (1992) Electrical Degradation and Breakdown in Polymers, IEE Materials and Devices Series 9, London, Peter Peregrinus Ltd. Doi, M. Edwards, S. F. (1986) The Theory of Polymer Dynamics, Oxford, Oxford University Press. 

Electrical degradation and breakdown phenomena [23] limit the utility of polymers in many applications ranging from electrical cable insulation to uses in advanced electronic devices. The key property of a polymer in relation to its electrical degradation and breakdown behavior is its dielectric strength. This property cannot be predicted quantitatively as a function of the polymeric structure at this time. However, because of its importance, we will discuss it briefly. 

L. A. Dissado and J. C. Fothergill, Electrical Degradation and Breakdown in Polymers, Peter Peregrinus Ltd., London (1992). 

Zakrevskii VA, Sudar NT, Zaopo A, Dubitsky YA (2003) Mechanism of electrical degradation and breakdown of insulating polymers. J Appl Phys 93 2135... 

To summarize, there is no well-defined total strain at which multifilamentary NbaSn wire electrically degrades—it varies from specimen to specimen, depending on the amount of prestress present in each. The wire can be fabricated and heat treated to optimize /c, as in curves 1, 2, 3, and 4 in Fig. 8, or to optimize strain tolerance, as in curve 7. The difference is that in the first case the compressive stress on the NbaSn was minimized, while in the second case it was maximized. These results indicate, however, that there is a well-defined intrinsic strain at which the NbsSn itself degrades. Critical current degradation becomes significant (exceeds 5 % ) at about 0.2% intrinsic strain. For the remainder of this paper, only the intrinsic strain experienced by the NbsSn reaction layer will be considered. 

Figure 14.2(a) Data from Chiang, Y-M., Kingery, W.D., and Levinson, L.M. (1982) Compositional changes adjacent to grain boundaries during electrical degradation of a ZnO varistor, J. Appl. Phys. 53, 1765. 

Electrical insulation n. Material with very low conductivity, which surrounds active electrical devices. Common electrical insulation chemicals are fluorine-containing polymers. Dissado LA, FothergUl CJ (eds) (1992) Electrical degradation and breakdown of polymers. Institution of Electrical Engineering (lEE), London. Ku CC, Liepins R (1987) Electrical properties of polymers. Hanser Publishers, New York. 

Nova Science Publishers Inc., New York. Dissado LA, Fothergill CJ (eds) (1992) Electrical degradation and breakdown of polymers. Institution of Electrical Engineering (lEE), London. 

Dissado, L. A. Fothergill, J. C. 1992. Electrical degradation and breakdown in polymers, London, P. Peregrinus. 

A number of factors must be considered when specifying contact materials. Several principles apply to the substrate. The normal force provided by the contact must be great enough to hold the battery in place (even when the device is dropped) and to prevent electrical degradation and any resulting instability. Contacts must be able to resist permanent set. This refers to the ability of the contact to resist permanent deformation with a set number of battery insertions. Temperature rise at high current drains due to the resistance of the contact material must be limited. Excessive temperature increase could lead to stress relaxation and loss in contact pressure as well as to the growth of oxide films which raise contact resistance. 

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