| 摘要 |
1,155,363. Coated insulators. CHAMPION SPARK PLUG CO. 13 April, 1966 [14 April, 1965], No. 16223/66. Heading B2K. [Also in Division F1] A method of providing an insulator body consisting principally of alumina with an electrically semi-conductive region comprises bringing a surface of said insulator into contact with cuprous oxide for a time and temperature sufficient that an electrically semiconductive region is provided at and beneath the surface of the insulator body. In a preferred embodiment, the insulator is brought into contact with a mixture of copper in a form which establishes equilibrium with oxygen at elevated temperatures, chromium sesquioxide and alumina and the temperature and time of contact is controlled to change the surface region of the insulator into chromates and aluminates of cuprous oxide without appreciable migration of the alumina of the insulator. |
