The electric strength of solid dielectrics

Review and Mechanism of the Thickness Effect of Solid Dielectrics

“…The expression in Equation (10) is also called the minus power relation since it can be transformed into: where E 1 = 10 G . In 1964, F. Forlani put forward a model for the thickness effect by taking into account the electron injection from cathode and the electron avalanche in dielectrics together [ 40 , 41 ]. After a series deduction, he found that: …”

“…In Forlani’s model, the electrodes and the dielectric were considered together for the occurrence of a breakdown [ 40 , 41 ]. The basic starting point of this model can be written as follows: where j ( d ) represents the current density when the seed electrons leave the cathode with a distance of d ; j i represents the current density near the cathode; P denotes the probability for electrons to change from the stable state to an unstable state, which can also be considered as the probability of an avalanche forming; α is the ionization coefficient, which means that α times of impacts to the atoms can take place when an electron moves a distance of 1 cm along the inverse field direction in dielectrics; exp( αd ) represents the increasing times for one seed electron moving along a distance of d .…”

Electric Breakdown Model for Super-Thin Polyester Foil

“…Frohlich high-energy criterion is based on that an applied field sufficient only to accelerate electrons already having the ionization energy may lead to an instability and to electric breakdown (Callen, 1949;Cooper, 1966).…”

Dielectric Breakdown in Solids

“…Materials of higher dielectric constant, however, seem to have systematically lower breakdown strengths than those with low dielectric constants. The statistical nature of breakdown has been investigated [13].…”

“…model, a decrease in breakdown voltage with increasing temperature is plausible because bonding strengths decrease with increasing temperature. Cooper [13] has shown that there is a rough correspondence between the shapes of the breakdown field versus temperature and Young's modulus versus temperature curves for many materials. The situation is not clear cut, however, since the fracture properties of materials vary in a complicated fashion with temperature and with the type and density of imperfections.…”