HEATING ELEMENT AND METHOD FOR PRODUCING THE SAME

摘要

For producing a heating element with a high heat-up rate and a predetermined resistance value for igniting airbag systems, a base member made of an aluminum oxide ceramic material is provided with a glass or glass ceramic coating. A layer of AuPd resinate is applied by screen printing over a large area of the ceramic coating which, if necessary, can be lapped and polished. The resinate layer is subsequently etched to form a resistive path having area-wise constrictions. The ends of the resistive path are subsequently contacted by a AgPd thick-film conductive paste, wherein the Pd content of a conductive paste determines the desired resistance value. After the thick-film conductive paste is dried and fired, the coated base member is subjected to a thermal treatment at temperatures in the range of 850-950° C. until the palladium in the resistor layer is uniformly distributed and the resistance value is stable. Thereafter, solder-resistant dams in the form of glass stripes are applied on the marginal edges of the AgPd contacts facing the resistive path, thereby decreasing the risk that the resistive path de-alloys in a subsequent soldering process.