Materials Issues Relevant to the Development of Future Metal Foil Automotive Catalytic Converters

摘要

Metal supported automotive catalytic converter bodies are based on ferritic steels, with 5-8wt%Al, 17-22wt%Cr plus small additions of reactive elements. To improve the catalyst performance there is a continued drive towards higher operating temperatures, thinner components and alternative geometries offering large surface area to volume ratios. Maintaining acceptable component lives is mandatory, even when thinner support geometries and higher operating temperatures are envisaged. This has led to a number of materials development strategies, including alternative substrate geometries, modifications to the alloy composition, both through the addition of multiple reactive elements and through the close control of trace element additions, and the development of surface treatments to increase the available aluminium reservoir. Each of these strategies will be reviewed. Service life predictions, not only relies on suitable materials, but also on the existence of adequate models and simulation techniques, supported by reliable data. In the present paper, the latest thoughts on modelling the oxidative failure of the FeCrAlRE based materials will be presented.