Dielectric and thermal properties of composite radome material under accelerated aging: an experimental study
摘要
This work aims at investigating the dielectric and thermal properties of silica fiber/epoxy(SiO2/E) composite radome material subjected to 30 days of accelerated hygrothermal aging at 5 °C, 50 °C, 70 °C, and 80 °C. X-ray diffraction showed a Bragg angle (2θ) from 20° to 22.5°, while no noticeable change was observed in the morphology of SiO2/E composite radome materials, except fewer microcracks were seen (SiO2/E(5)) when exposed to 5 °C. Among the aged SiO2/E(5), SiO2/E(50), SiO2/E(70), and SiO2/E(80) composite radome material samples small variation was observed in the electrical and thermal properties except for SiO2/E(5), where the highest increment in dielectric constant (Ɛr) was noticed from 3.95 to 4.01, dielectric loss (δ) from 0.045 to 0.051, and fractional transmission was degraded 10.5% from its initial value. For SiO2/E(5) composite radome material, the maximum moisture (1.83%) was absorbed in the traverse fiber direction, while the thermal expansion coefficient (α) declined from 5.83 × 10−6 K−1 to 5.76 × 10−6 K−1, and thermal conductivity(k) dropped from 0.399 to 0.394 Wm−1K−1. However, in the SiO2/E (80) composite radome material exposed to 80 °C, the thermal conductivity was raised to 0.409 Wm−1K−1, along with less thermal degradation (23.42% weight loss) than other SiO2/E composite radome material samples exposed to 5 °C, 50 °C, and 70 °C. However, the Ɛr and δ of SiO2/E(5) (aged at 5 °C) were increased to 1.5% and 1.1.3%. It was interesting that hygrothermal accelerated aging from ambient to 80 °C did not bring any substantial change in dielectric and thermal properties of SiO2/Ex composite radome material, which reveals its sustainable performance in long-term microelectronic applications.