| 摘要 |
874,157. Resistive coatings. DU PONT DE NEMOURS & CO., E.I. Oct. 28, 1959, No. 36583/59. Class 37. [Also in Group XXIII] A -vitreous enamel composition to be applied to and fired on a ceramic dielectric to form electric resistors comprises by weight 92 to 73% enamel flux and 8 to 27% of palladium, or, in a modification, a proportion of the palladium is replaced by finely divided silver, the composition containing a minimum of 4% palladium. The enamel flux used may be a borosilicate frit or lead, cadmium, barium, calcium or other borosilicate frit and may also contain zinc or magnesium oxide. 30-95% of Bi2O3 or PbO may be added to improve the reproducibility of given resistance values. Finely divided Pd, Ag and the frit, average particle size 0.1 to 50 microns, are ball milled and mixed with a liquid vehicle which may be water or an organic solvent, and applied by brushing, spraying, printing or squeegee screen stencil application and then fired. Specific examples are given. Specifications 816,799 and 849,305 are referred to. |
