| 摘要 |
<p>486,829. Asymmetrically - conducting resistances. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. Aug. 10, 1937, No. 22000. Convention date, Aug. 13, 1936. [Class 37] In an electrode system having two eleetrodes of different conductivity, one of which is a selenium electrode, separated by an insulating blocking layer, the blocking layer is at least partly constituted by a stable, solid, insulating chemical compound, the substance cap - able of yielding this compound by chemical conversion being present as an addition in the selenium electrode. In the example shown the selenium layer 3 is deposited on a carbon layer 2 on the aluminium support 1. The blocking layer 4 is formed on the selenium, and upon this is sprayed a conductive alloy to form layer 5. The additions to the selenium are one or more easily volatile halides which readily hydrolyze with water. A list of suitable halides is given in the Specification. The halides are added either directly to molten selenium, the mixture being afterwards distilled, or by vaporizing them in a current of gas which is then passed through the molten selenium previously distilled The selenium is then pressed on a metal support, the blocking layer being formed on the side of the selenium remote from the support by the chemical reaction, whilst being heated, of the added halide with a substance having an alkaline reaction. This substance may be an alkali such as caustic soda or potash lye or an organic substance such as pyridine or aniline in a solvent having a high boiling point such as glycerine or quinoline. Specification 468,736 is referred to.</p> |
