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This study presents a stainless steel most suitable as the metal base material for the weight sensor substrate of automobile airbags. The influence of the chemical compositions of both Al and Cr on average linear expansion coefficient and high temperature oxidation resistance was examined in order to develop the proposed stainless steel sheet. As a result, it was found that by using a stainless steel sheet comprising high-aluminum ferritic stainless steel containing over 2.5mass%Al, it is possible to control the difference between the average linear expansion coefficients of the proposed stainless steel sheet and crystallized glass for a weight sensor in a temperature range from 20°C to 900°C. Thus, it is also possible to improve the adhesiveness between the proposed stainless steel sheet and crystallized glass. Furthermore, it was observed that the high temperature oxidation resistance improves remarkably with the increase in Al content.

Recently, a metal support catalyst has been successfully developed and its use has been gradually increasing because of its advantages over the conventional ceramic support. The material properties required of an automotive catalytic converter are expected to increase in severity with intensifying environmental regulations on a worldwide level. This study examined the material properties required of an Fe-Cr-Al alloy foil for a metal support having increased heat resistance. First, the effect of rare earth metals against high temperature oxidation resistance of the Fe-Cr-Al alloy foil is examined and the developed alloy is proposed. Second, the durability of the metal support is discussed. Third, the accelerated creep elongation caused by the growth of an oxide film when catalyst related material is loaded, is described and the influence on the performance of the metal support is discussed.

A metal support for use in an automotive catalyst is exposed to the severe heat cycle brought about by the intermittent flow of a high temperature exhaust gas. Accordingly, the metal support must have high beat resistance(ex. oxidation resistance) and a rigid structure. Therefore, 20% chromium-5% aluminum ferritic stainless steel(containing small quantities of rare earth metals and titanium) is used as a highly beat resistant honeycomb foil in addition to a highly mechanical durable brazing honeycomb structure. This study examined the durability of a metal honeycomb installed in a gasoline engine. Both an engine bench durability test of a manifold converter type metal support which is connected directly to the exhaust manifold of the gasoline engine and a vehicle durability test of an under the floor type metal support were carried out to evaluate oxidation damage of the metal honeycomb as well as its mechanical durability.