摘要 |
An oxygen sensing probe of the type in which a sensor tip made of a solid electrolyte is secured within a supporting tube by an hermetic seal. The tip is made of yttria-stabilized zirconia; the tube is made of magnesium-aluminate spinel, calcia and zirconia; and the tip and the tube are bonded together by a fusion weld consisting of a eutectic mixture of the tip material and the tube material. The coefficient of thermal expansion of the tube material very closely matches that of the tip material so as to prevent the seal from cracking when the probe is cycled rapidly and repeatedly through a wide temperature range. A frustoconical shoulder on the sensor tip engages a slotted frustoconical seat within a tubular outer conductor to establish good electrical contact between the tip and the electrode while allowing gas to circulate freely past the tip.
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