Oxygen determn. appts. esp. for exhaust gas from motor vehicles - using thin solid electrolyte coated on each side with thin metal film electrode to make probe which can be rapidly heated

摘要

Gas analysis appts. has a first thin film electrode (a) made of a catalytic electronic conductor through which oxygen atoms can flow and 0.1-1 micron thick. Film (a) is esp. porous Pt, and is located on one side of a thin film (b) of solid ceramic electrolyte, which conducts ions and through which oxygen atoms can flow. Film (b) is 0.2-1.0 mm. thick, and its other side is coated with a film (c), 0.1-1 micron thick, of an electronic conductor, usually Au or Ag, and forming a second electrode. The assembly of films has a low thermal inertia, so it can be heated in a few seconds to min. 300 deg.C; and pref. consists of a tube or a cone. The low thermal inertia means that the assembly of films or probe can be heated very rapidly so the catalytic electrode (a) is not poisoned at low temp. by tetraethyl lead.