PURPOSE: To improve water repellent and electrical insulating properties and maintain characteristics for a long period by forming a coat including a film made of ceramic material with a repellent property on its surface or the ceramic material.
CONSTITUTION: A coat including a film made of ceramic material with a water repellent property on its surface or the ceramic material is formed. As the repellent coat, a coat with eveness and strong binding property is used, which is formed of a ceramic material excellent in its weather resistance and having an electrical insulating property, such as BN, Si3N4, SiC, SiO2, TiO2, Al2O4, AIN, amorphous diamond which is used as a mono-layer or with an intermediate layer, by the physical vapor deposition method(PVD) or chemical vapor deposition(CVD). It is thus possible to prevent decrease of the electrical property of an insulator produced by the above-mentioned method owing to the repelling property of the coat.
IGAMI SHUNICHI
NAKAJIMA ISAO
NAKAI TAKAO
NGK INSULATORS LTD