Abstract
Abstract
This study presents a new probe to analyse the gas composition near a metal surface. The probe uses a mass spectrometric detector and is incorporated in an experimental reactor for the thermal treatment and surface formation of steel sheet samples. Steel samples were exposed to various oxidizing and reducing gas flows at pressures between ambient and 3 bar. The reaction product H2O was measured with the MS‐probe while reducing oxidized steel surfaces with H2as well as the consumption of H2as a function of the sample temperature. Similarly, the reaction products CO and H2were monitored during the oxidation of the bulk carbon with H2O. The sample temperature was ramped linearly from ambient to 900 °C. From these measurements it was possible to evaluate the onset temperatures and the activation energies for the respective reactions. The in‐situ monitoring of the gas phase near the steel surface within the experimental reactor allows controlling the formation of a layer of iron as a result of the iron oxide reduction. Similarly, the decarburization of steel can be followed up by measuring the time course of the CO concentration. It is expected that the MS‐probe will become an efficient tool for the understanding and optimization of the annealing and formation processes during strip annealing before hot dipping.