A ceramic heater including a ceramic body and a heating element buried in the ceramic body under the surface of thereof is provided, wherein metal pads are disposed on the outside of the ceramic body and electrically connected to the heating element, outer leads are joined by a braze layer onto a metal plated layer covering each of the pads, and the braze layer contains an amount of 500 ppm or less by weight of palladium in a brazing metal material based on Au, Cu, or Ni. The plated layer may be formed on the surface of the metal pads which have been activated with an activating solution containing an amount of 90 ppm of less by weight of Pd, in order to reduce the Pd content as defined above in the braze layer, preventing the braze layer from being cracked and enhancing the useful life of the ceramic heater.
A joint structure which does not exhibit impaired joining strength induced by exposure to heat cycles and the occurrence of migration, in a ceramic heater for a glow plug or like device. A heating element 6 is embedded in a silicon nitride ceramic substrate 5. Lead wires 15 are joined to corresponding lead wire connection terminals 11, which are connected to the heating element 6 while electrical continuity is established therebetween, by use of a brazing metal 20 which contains a predominant amount of copper. The brazing metal 20 used for joining assumes the form of a brazing metal layer having a thickness of 30-400 .mu.m.
An electrical resistance heating cable, including a resistance heating wire having a resistive conductor, an insulation at least partially surrounding said resistive conductor; and an end. A crimp connector is connected to the end. A thermally conductive sleeve at least partially surrounds the end and is positioned between the crimp connector and the insulation.
A ceramic heater including a ceramic body and a heating element buried in the ceramic body under the surface of thereof is provided, wherein metal pads are disposed on the outside of the ceramic body and electrically connected to the heating element, outer leads are joined by a braze layer onto a metal plated layer covering each of the pads, and the braze layer contains an amount of 500 ppm or less by weight of palladium in a brazing metal material based on Au, Cu, or Ni. The plated layer may be formed on the surface of the metal pads which have been activated with an activating solution containing an amount of 90 ppm of less by weight of Pd, in order to reduce the Pd content as defined above in the braze layer, preventing the braze layer from being cracked and enhancing the useful life of the ceramic heater.
A method for making a heating element adhered to a substrate by applying a photocurable composition to a flexible substrate in a pattern having one or more grid lines is provided. The photocurable composition is curable into an electrically conductive layer and volatile organic compounds are present in an amount of less than about 10% total weight of the photocurable composition. After the pattern is deposited on the substrate is cured by illuminating the photocurable composition with light for a sufficient period of time to cure the photocurable composition. Heating elements made by the method are also provided.
