Advantages of silicone oil:
(1) The viscosity temperature performance is the best among the liquid lubricants, and the viscosity changes little in a wide temperature range. Its freezing point is generally less than – 50 ℃ and some as high as – 70 ℃. The appearance and viscosity of the oil remain unchanged after long-term storage at low temperature. It is a base oil with high temperature, low temperature and wide temperature range. (2) Excellent thermal oxidation stability, such as thermal decomposition temperature > 300 ℃, low evaporation loss (150 ℃, 30 days, evaporation loss is only 2%), oxidation test (200 ℃, 72h), viscosity and acid value change little.
(3) Excellent electrical insulation, volume resistance, etc. do not change in the range of normal temperature to 130 ℃ (but the oil can not contain water).
(4) It is a non-toxic, low foaming and anti foaming oil, which can be used as defoamer, etc.
(5) Excellent shear stability, can absorb vibration, prevent vibration propagation function, can be used as damping fluid.
Silicone oil disadvantages
(1) The lubricity of silicone oil is not good, especially for steel friction pair.
(2) The thermal expansion coefficient of silicone oil is large (overpressure may occur).
(3) The solubility of gas is high (it is difficult to design gas seal device).
(4) It has a certain hygroscopicity (when the water content is higher than 100 × 10 – 6, the electrical properties decrease sharply).
(5) Low surface tension (easy to leak from the machine).