Patents Assigned to E. R. A. Patents Limited
  • Patent number: 4044173
    Abstract: Process for forming a vitreous enamel electrical resistor coating on a substrate, said vitreous enamel containing an electrically conductive species as a crystalline phase and having a temperature coefficient of resistance, as measured in the temperature range of 20.degree. to 120.degree. C, of from -500 to +500 ppm/.degree. C, comprises applying to said substrate a paste comprising (1) an organic medium, (2) a powdered aluminoborate glass containing dissolved molybdenum trioxide, tungsten trioxide, cerium dioxide, manganese dioxide or ferric oxide in an amount of 2 to 30 mol percent of the total constituent oxides of the glass and (3) powdered boron, silicon, molybdenum disilicide or tungsten disilicide in an amount of 0.25 to 30 percent by weight based on the total weight of components (2) and (3) and firing the paste on the substrate at a temperature of about 600.degree. to 900.degree. C to form a vitreous enamel. The coated substrates are particularly useful in thick film printed and fired circuits.
    Type: Grant
    Filed: October 31, 1974
    Date of Patent: August 23, 1977
    Assignee: E. R. A. Patents Limited
    Inventor: Alexander S. Laurie