IMPROVEMENTS RELATING TO RESISTORS

1,262,554. Resistors. B. A. BOCHKAREV, and V. A. BOCHKAREVA. 18 Sept., 1969, No, 46110/69. Heading HIS. [Also in Division C7] A metal/dielectric resistor is formed by sublimating in a vacuum on to an insulating substrate (e.g. ceramic) an electrically conductive coating containing a conductive component and a dielectric component and subsequently heating the resistor until the coating is softened and densified, the dielectric component including at least one metal oxide melting in the temperature range 350‹-700‹ C. The dielectric component may include vanadium oxides or barium oxide and the conductive component may include lead oxide. The resistive layer may be produced using a mixture of powders A and B, powder A containing 13À8% of chrome by weight, 55À4% silicon, 10À4% aluminium and 20À4% lanthanum oxides, whilst powder B contains vanadium oxides. From 80-95% of powder A is mixed with from 5-20% of powder B first as a dry compound and then with any neutral volatile solvent such as alcohol or acetone. The mixture is then dried and sifted through a sieve having 1000 holes per sq. cm. It is then deposited by sublimation in vacuum on to insulating bases to make resistor blanks. The blanks are subsequently heated in air or a vacuum at a temperature of 300‹-750‹ C. for a period from five minutes to a few hours. In an alternative method the ingredients for a conventional metal-dielectric layer are vacuum evaporated simultaneously with the evaporation of oxides which, with some of the evaporated ingredients, are capable of forming compounds which soften during the subsequent thermal treatment.