| 摘要 |
814,913. Thermistors. PHILIPS ELECTRICAL INDUSTRIES Ltd. Jan. 28, 1957 [Jan. 31, 1956], No. 2982/57. Drawings to Specification. Class 37. A sintered electrical resistor with a negative temperature coefficient comprises nickel oxide having a lithium oxide content of from 0.1 to 10 mol. per cent and a copper oxide content (calculated as CuO) of from 1 to 30 mol. per cent. The oxides of nickel, lithium and copper (or substances which change to the oxides when heated) are mixed together and moulded whilst adding a binding agent. The mixture is then sintered in an oxidizing atmosphere, preferably air, at a temperature preferably between 1, 100‹ and 1, 300‹ C. A method of making a more conventional resistor is described whereby nickel oxide with lithium carbonate added in such an amount that the mixture contains 1.5 mol. per cent of Li 2 O is ground in a ball mill with alcohol (previously saturated with lithium carbonate) for 16 hours. The product is filtered and dried and then a binding agent consisting of a solution of 2 gms. of methyl acrylate with 1 ml. of dibutyl-phthalate in 100 mls. of methyl acetate is added at the rate of 5 gms. per 100 gms. of powder. Rods of 5 x 5 x 15 mms. are moulded from this mass and sintered in air at 1, 240‹ C. for one hour. Table 1 in the Specification gives examples of the impurities such as Si, Te, Co, Cr, Mn, Mg, Pb, Bi, Al, Sn, Ca, Cu, Ag, Na, Zn, As and Cd, which may be present in six different samples of nickel oxide from different sources. |
