Abstract: A contact glass composition for use in resistor-type spark plugs is described. The contact glass composition is a mixture of: (a) at least one metal; (b) graphite; and (c) silicon. Additionally, borosilicate glass, barium borate glass, magnesium aluminum silicate, ball clay, and aluminum may also be included in the contact glass composition.

Abstract: An activated solid electrolyte oxygen gas sensing element with increased voltage output, shortened switching time and reduced internal resistance, the sensing element having inner and outer conductive catalyst electrodes thereon, is produced by subjecting the outer surface with the outer electrode to a nonoxidizing atmosphere and applying a direct current to the element while the same is at an elevated temperature, the current being applied with the outer electrode as an anode.

Abstract: An activated oxygen gas sensor element having an increased voltage output under rich gas conditions, short switching response and reduced internal resistance is produced by chemically treating the inner conductive catalyst electrode of the sensor element with an inorganic acid or acid salt and current activating the outer conductive catalyst electrode by applying a direct current to the sensor element, with the outer electrode as a cathode, while the outer electrode is at an elevated temperature and in the presence of a neutral or inert atmosphere. Air may be used as the atmosphere in contact with the outer electrode during the current activation provided that the sensor is subjected to a subsequent reheating step to provide the desired results.

Abstract: An activated oxygen gas sensor element having an increased voltage output under rich gas conditions, short switching response and reduced internal resistance is produced by chemically treating the inner conductive catalyst electrode of the sensor element with an inorganic acid or acid salt and current activating the outer conductive catalyst electrode by applying a direct current to the sensor element, with the outer electrode as an anode, while the outer electrode is at an elevated temperature and in the presence of a nonoxidizing atmosphere.

Abstract: An oxygen gas sensor having a solid electrolyte oxygen gas sensor element, with an inner conductive catalyst electrode on the interior surface and an outer conductive catalyst electrode on the exterior surface thereof, which has a high voltage output and lower internal resistance is produced by chemically activating said inner conductive catalyst electrode with an inorganic acid or an acid salt. By also subjecting said outer conductive catalyst electrode to a direct current activation under a reducing atmosphere, even more improved properties, such as fast switching response, are achieved.