A Study on the Durability of Thin Electric Insulation Layers Coated on Condenser Cases by Plasma Polymerization

Thin electric insulation layers were coated on aluminum plates and aluminum condenser cases by plasma polymerization of HMDSO+. Electric resistances of the films were higher than 1.0 M if they are thicker than 0.5 independently of the type of films but their surface morphologies and adhesion strengths were dependent on the process conditions. Deposition rate and adhesion strength of the films were dependent on /HMDSO flow ratio and discharge power. The best result was obtained at /HMDSO flow ratio of 4 and discharge power of 60 W. Adhesion strength could also be highly improved if aluminum was pre-treated in boiling water for 30 min through the formation of Al-O-Si bonding between the film and the aluminum surface. The coated films showed excellent chemical and thermal resistances.