Using Isothermal Aging to Evaluate Filled Silicones for Low and High Power Electronics

摘要

Silicones are a common electronic pottant used to protect fragile components from mechanical shock, thermal degradation and electrical shorts (Johnson 2004). A successful pottant must sustain its cured mechanical, thermal and electrical properties after years of operation. During this study, the durability of these properties was evaluated in commercially-available silicones. Specifically, durometer, ultimate tensile strength, elongation to break, thermal conductivity, dielectric constant and dissipation factor were evaluated before and after isothermal aging at room temperature, 100℃, and 150℃. After 1,300 hours of aging, the products with lower filler content did not show any large property changes. Therefore, these silicones are an ideal candidate for low power electronics. Unfortunately, when the same three products were evaluated at 275℃, all three showed large decreases in durometer and tensile strength. For this reason, they are not well suited for use as pottants in high power electronics.