Analysis of dielectric breakdown failure and electric field distribution in polymer-coated boroaluminosilicate glass through simulation and experimental measurements

Parylene C coating is used to mitigate local electric field intensification in high-alkali BAS (Schott D263T) glass and low-alkali BAS glass (Schott AF32) with the aim of improving the dielectric breakdown characteristics. The breakdown events in these glasses were analyzed using a two-parameter Weibull probability distribution. Our findings demonstrate that the parylene C coating effectively mitigates the intensified electric field and reduced the risk of surface damage from thermal shock. Consequently, the weakest breakdown events are shifted to higher breakdown voltages and longer times, leading to a significant increase in the Weibull modulus. For anode-coated D263T glass, the Weibull modulus increases from 19.90 to 45.88 (a 130.55% enhancement), while for anode-coated AF32 glass, the increase is from 3.82 to 28.53 (a 646.86% enhancement), compared to uncoated glass. Although cathode-coated glass also demonstrates an improvement in the Weibull modulus, the enhancement is not as substantial as that observed in the anode-coated glass. Furthermore, we employ a finite element analysis model to simulate our experimental observations, aiming to enhance our understanding of the impact of polymer coatings on the dielectric breakdown of glasses with spatial and compositional fluctuations.