Viton® (Fluorocarbon) O-Ring:
• Viton® (Fluorocarbon) is normally used in vacuum service. Viton® has a low porosity to most gases and withstands high temperatures up to 200°C for short periods.
200°C Maximum, Chemical Applications
• Silicone is used in chemical applications and can withstand temperatures of 200°C for short periods, but silicone tends to harden to prolonged high temperature service, sticking to the metal surfaces and making the o-ring difficult to be replaced. Silicone is also very porous to helium.
• Buna-N is low cost, but their maximum operating temperature of 100°C makes them unacceptable for many high temperature vacuum applications.