MANUFACTURING METHOD OF GAS-DETECTING ELEMENT

PROBLEM TO BE SOLVED: To provide a manufacturing method of gas-detecting element, improved in the stability of welding of a lead wire, electrically connecting between a gas sensitive section and an external connection terminal. SOLUTION: An end of a lead wire 16, consisting of an alloy of gold, palladium, and molybdenum is connected electrically and mechanically to each electrodes 12A, 12B, 13A', and 13B' of an alumina substrate 11, at one side surface of which a gas sensitive section consisting of metal oxide semiconductor, is formed and at the other side surface of which a heater 14 is formed to heat the gas sensitive section; while after forming a nearly spherical jointing section 16a with a diameter larger than the wire diameter at the other end of the lead wire 16, this junction section 16a is made to contact the terminal 4, and in a state with the electrodes made to contact the junction section 16a and the terminal 4, respectively, by turning on the electricity between the both electrodes, the contact site of between the junction section 16a and the terminal 4 is melted by the electrical resistance heating and thus the other end of the lead wire 16 is jointed to the terminal 4. COPYRIGHT: (C)2006,JPO&NCIPI