Degradation Behavior and Failure Mechanisms of Silicone Rubber in a Simulated Marine Atmospheric Salt Spray Environment

Silicone rubber, widely used as a sealing material in aerospace and marine equipment, plays a crucial role in ensuring operational reliability and safety. However, in the harsh marine atmospheric environment characterized by high salinity and humidity, the degradation behavior of silicone rubber differs significantly from that in inland environments, with the failure mechanisms still remaining unclear. To address the challenges of prolonged natural aging and unclear degradation behavior, this study established an accelerated aging platform in the laboratory and designed a neutral salt spray accelerated aging test. Through comprehensive analyses of macroscopic physical properties (weight loss, compression set, etc.), microstructure (XPS, SEM), and mechanical properties (tensile strength), the study systematically explores the performance degradation of silicone rubber under simulated marine atmospheric conditions with high salt spray and summarizes the failure mechanisms at various stages. The results indicate that the degradation of silicone rubber in a neutral salt spray environment can be divided into three stages, with Cl-ions playing a pivotal role. In the initial stage, Cl-rapidly penetrates the material; in the middle stage, the degradation slows down, and differentiation between the inner and outer layers becomes apparent; in the final stage, the degradation stabilizes, and the microstructure exhibits numerous through-holes, ultimately leading to material failure. These findings provide a basis for predicting the remaining service life of silicone rubber and help improve its reliability and durability in marine environments.

Keywords: Silicone rubber, Accelerating test, Degradation behaviour, Failure mechanisms, Marine atmospheric salt spray environment, Reliability and durability.