1. The surface tension is small (easy to leak from the machine).
2. Gas solubility is large (it is difficult to design a gas seal device).
3. Silicone oil has a large thermal expansion coefficient (probably overpressure problem).
4. Silicone oil has poor lubricity, especially for steel steel friction pairs.
5. A certain hygroscopicity (after the water content is higher than 100×10-6, the electrical performance drops sharply)