Disadvantages of silicone oil
(1) The lubricity of silicone oil is poor, especially for steel steel friction pairs.
(2) The thermal expansion coefficient of silicone oil is relatively high (which may cause overpressure problems).
(3) Gas solubility is high (difficult to design gas seal devices).
(4) A certain degree of moisture absorption (when the water content exceeds 100 × 10-6, the electrical performance sharply decreases).
(5) Low surface tension (prone to leakage from the machine).