Silicone oil can be several degrees below zero High temperature resistant silicone oil, heat transfer oil, just what you want for low temperature minus 50 degrees.
High temperature can be used for 350 degrees. Ordinary silicone oil: [English name] Silicone oil [other name] cyclic polydimethylsiloxane [chemical formula] (CH3)3SiO[(CH3)2SiO]n
Si(CH3)3【melting point】
50℃【boiling point】101℃【density】0.963【appearance】colorless, odorless, non-toxic and non-volatile liquid 【flash point】300℃ 【application】advanced lubricating oil, shockproof oil, insulating oil, defoamer, mold release agent
【advantage】
(1) The viscosity-temperature performance is the best among liquid lubricants, and the viscosity changes little in a wide temperature range. Its freezing point is generally less than
50 ℃, some as high as 70 ℃, long-term storage at low temperature, the appearance and viscosity of the oil have no change, it is a base oil that takes into account high temperature, low temperature and wide temperature range.
(2) Excellent thermal oxidation stability, such as thermal decomposition temperature>300℃, small evaporation loss (150℃, 30 days, evaporation loss is only 2%), oxidation test (200℃, 72h), viscosity and acid value Small changes.
(3) Excellent electrical insulation, volume resistance, etc. remain unchanged in the range of normal temperature to 130 °C (but the oil cannot contain water).
(4) It is a non-toxic oil with low foaming and strong anti-foaming properties, which can be used as a defoaming agent.
(5) Excellent shear stability, has the function of absorbing vibration and preventing vibration transmission, and can be used as vibration damping fluid.

【shortcoming】
(1) The lubricity of silicone oil is not good, especially for the friction pair of steel and steel.
(2) The thermal expansion coefficient of silicone oil is large (may cause overpressure problems).
(3) The gas solubility is relatively large (it is difficult to design a gas sealing device).
(4) Certain hygroscopicity (after the water content is higher than 100×106, the electrical properties drop sharply).
(5) Small surface tension (easy to leak from the machine).