(1) the lubricity of silicone oil is not good, especially for steel friction pair.

    (2) the coefficient of thermal expansion of silicon oil is large (may cause overpressure problem).

    (3) High solubility of gas (difficult to design gas seal device).

    (4) a certain hygroscopicity (after the water content is higher than 100×10-6, the electrical performance decreases sharply).

    (5) The surface tension is small (easy to leak from the machine).