Method for measuring of a gaseous atmosphere in a low pressure carburizing furnace, for nitriding or nitrocarburizing and probe for realising this measurement

摘要

Measuring a gaseous composition in a low pressure case hardening furnace using a nitriding or nitrocarburising atmosphere comprises injecting an oxidizing gas via a guide tube (14) insulated from the furnace, into a reactor (28) in which the oxidising gas is mixed with a gas sample from the furnace in the reactor, where it reacts to give a new sample E of oxygen concentration X. The new sample is applied on one face of the solid electrolyte (29). A gaseous reference sample F, F1 of oxygen concentration X1, X2 is also applied to the other face of the solid electrolyte (29) and the potential difference is measured by way of the electrodes (31, 33). This pd is due to the differing oxygen concentrations X and X1, X2 between the samples E and F, F1 on both sides of the solid electrolyte. The ratio of the partial pressures of oxygen from different atmospheres is determined and from this can be calculated the concentration of carbon or the nitriding or nitrocarburising potential. Also claimed is a sensor unit for measurement as above.