METHOD FOR CATALYTICALLY COATING CERAMIC HONEYCOMB BODIES

摘要

In the application of a catalytic washcoat to an automotive ceramic catalytic converter with a honeycomb structure, the pore inlets and outlets are opened and closed alternately at the end-faces. The catalytic washcoat flows from the inlet to the outlet prior to flow reversal. The washcoat is driven through the honeycomb either by suction or pump action. Alternatively, the catalytic converter is dunked in a washcoat bath, or doused with washcoat. Alternatively, the inlet/outlet pores are closed with a wax plug that is solid at the normal honeycomb processing temperature, and which melts or evaporates at higher temperatures, or is removed by a solvent. The wax melts at above 80[deg]C. The honeycomb body porosity is 30-90 and has a median pore diameter of 10-50 m. The washcoat concentration is 240 g/l.