| 摘要 |
995,972. Resistors. CORNING GLASS WORKS. May 23, 1963 [May 28, 1962], No. 20653/63. Drawings to Specification. Heading H1S. An electrical resistor comprises a ceramic substrate, an electro-conductive metal oxide as a primary conducting element, spaced terminal members in electrical contact with the primary conducting element, and a second metal oxide film intermediate the primary conducting element and the ceramic substrate, of relatively low conductivity compared with the primary conducting element and composed essentially of tin and antimony oxides. The term " ceramic " is used here in a generic sense to include glasses, glass-like materials, and conventional sintered ceramic materials. In one example, an essentially alkali-free, alkaline earth aluminosilicate glass cane of 0À141 inch diameter is contacted at a temperature of 650‹ C. with vapours from suitably proportioned solutions of the chlorides of tin and antimony. A solution of 1À00 gm. SnCl 4 .5H 2 O per 1 ml. of a solvent comprising 1 part cone. HCl and 5 parts H 2 O and a solution of 1À00 gm. SbCl 3 per 1 ml. of a similar solvent are prepared and mixed to provide a coating solution for the conducting film containing 97À75 vol. per cent SnCl 4 .SH 2 O and 2À25 vol. per cent SbCl 3 , also a coating solution for the intermediate film and a cover film containing 40 vol. per cent SnCl 4 .5H 2 O and 60 vol. per cent SbCl 3 . The thicknesses of these films are 600, 850 and 2300 A.V., respectively, and their resistances 500, 12500 and 75000 ohms, respectively. Application of terminal members on either end of the cane is followed by hermetic encapsulation of the coated cane in a glass envelope. Tests at 125‹ C. ambient temperature show a three-fold improvement in electrical stability compared with a similar resistance without the intermediate layer. The thickness of this layer does not appear to be critical, but should be at least several hundred A.U. to insure a continuous film. Its resistance should be such that it carries less than about 1% of the total current flow through the resistor. A slightly larger fraction, e.g. a few per cent, of the total resistor current may be carried by the intermediate film so as to provide a balanced temperature coefficient where the primary conducting element has a positive temperature coefficient but this will usually have an adverse effect on stability and may be utilized only where such an effect may be tolerated. Specifications 639,561, 806,189 and 806,190 are referred to. |
