| 摘要 |
PURPOSE:To enhance the long-lasting property of purifying capacity, by supporting a noble metal having catalytic action to the purification of exhaust gas by a honeycomb carrier. CONSTITUTION:Two kinds of alumina powders different in absorbing capacity are used. The alumina powder having high adsorbing capacity is added to an alumina sol solution to prepare an alumina slurry for an inner layer and a honeycomb carrier is immersed in this alumina slurry. This carrier is dried and baked to form a primary treated article wherein the carrier is coated with an alumina layer. In the next step, the alumina powder having low adsorbing capacity is added to the alumina sol solution to prepare an alumina slurry for an outer layer and the primary treated article is immersed in this slurry. Thereafter, the treated article is dried and baked to obtain a secondary treated article which is, in turn, immersed in a noble metal solution and the impregnated article is subsequently dried. |
