Semi-conducting materials and a method for the manufacture thereof
AssigneeUniversal Oil Products Company
InventorsKarl J. Youtsey, William C. Holt, Jr.
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Abstract
Semi-conducting materials which may be used in preparing resistors may be prepared by treating a refractory oxide with a pyrolyzable organic compound at an elevated temperature and thereafter further treating the resultant semi-conducting pyropolymeric inorganic refractory oxide composite material at an elevated temperature with subsequently controlled cooling rate to provide a material which possesses a lower resistivity and a controllable temperature coefficient of resistance over a wide range.
Claims10
A method of manufacturing a semi-conducting pyropolymeric inorganic refractory oxide material which comprises heating a refractory oxide in an oxygen-free atmosphere with a pyrolyzable organic compound at a temperature in the range of from about 400.degree. to about 800.degree.C. for a sufficient time to form a mono-layer of carbonaceous pyropolymer on the surface of said refractory oxide, thereafter further heating the resultant semiconducting pyropolymeric inorganic refractory oxide material in an inert atmosphere at a temperature higher than the firstmentioned temperature and in the range of from about 700.degree. to about 1200.degree.C. for a sufficient time to form a semi-conducting pyropolymeric inorganic refractory oxide material having a temperature coefficient of resistance in a range of from about +20,000 to about -20,000 ppm/.degree.C., and cooling and recovering the last-named material.
Dependencies are inferred from the claim text.