METALLIC SUBSTRATE FOR EXHAUST GAS PURIFICATION CATALYST AND ITS PRODUCTION

摘要

PURPOSE: To impart heat resistance to an iron or iron-based alloy honeycomb and to carry out high reliability joining between the corrugated foil and flat foil of the honeycomb while avoiding the remarkable deterioration of the material by joining the contact points of the foils and the contact points of the honeycomb and a jacket with diffusion layers enriched with Cr and Al. CONSTITUTION: When a metallic honeycomb 1 is subjected to cementation treatment so as to impart heat resistance and bonding strength, cementation treatment is carried out using a Cr-based diffusing agent whose Cr content is higher than the Al content. By this treatment, high reliability joining is carried out and satisfactory heat resistance is imparted in spite of such a relatively low extent of cementation as not to cause the remarkable deterioration of the material. When a diffusing agent contg. >=2 times (wt.) as much Cr as Al is used, the activity of Al is moderately controlled and the adhesion and cementation of Cr and Al are carried out at narrow-gap parts around the contact points of the corrugated foil 3 and the flat foil 2 of the honeycomb 1 as well as at the other part. As a result, joining is carried out with diffusion layers enriched with Cr at >=2wt.% concn. and Cr+Al at 12-30wt.% concn.