The key to selecting silicone oil for high-temperature applications lies in precise matching based on the specific temperature range, environmental medium, and rheological requirements to avoid oxidative degradation or carbonization.

First, the principle of thermodynamic temperature matching must be followed. For conventional scenarios where the long-term operating temperature does not exceed 200℃, dimethyl silicone oil can meet the requirements due to its excellent viscosity-temperature coefficient and cost-effectiveness. Once the critical point of 200℃ is exceeded, the oxidation rate of its main chain will increase exponentially. At this point, methylphenyl silicone oil with phenyl structures introduced into the side chains must be selected. The large π-bond structure of phenyl effectively disperses heat energy and significantly improves oxidation resistance, allowing it to remain stable even at extreme high temperatures of 200℃ to 300℃.

Second, the environmental medium and volatility must be considered. In open or aerobic environments, phenyl silicone oil is the first choice; however, in high-vacuum high-temperature systems, special diffusion pump oils with extremely low saturated vapor pressure must be selected to strictly control volatiles and prevent system backflow contamination. Furthermore, for water-based systems or room-temperature construction requirements, polyether-modified silicone oils can be selected. Finally, rheological viscosity design is equally crucial. High-temperature lubrication scenarios typically use medium-to-high viscosity (e.g., 500~5000 cSt) products to ensure oil film integrity; high-temperature demolding processes utilize lower viscosity (200~1000 cSt) products to facilitate uniform coating; while in damping and buffering systems requiring the absorption of high-frequency vibrations, ultra-high viscosity (above 10000 cSt) products are necessary. Only by comprehensively considering these factors can the long-term stable operation of high-temperature systems be guaranteed.