| abstract |
A ceramic honeycomb wall-flow filter is prepared by plugging channels in a clay containing ceramic honeycomb by a method that has the following steps. First, a mixture of a dispersing liquid and ceramic powder is formed. Second, the mixture is inserted into at least one channel of a clay containing green ceramic honeycomb to form a plugged green ceramic honeycomb wherein the dispersing liquid essentially fails to swell the clay. Alternatively, the mixture is inserted into a calcined ceramic honeycomb to form a plugged calcined ceramic honeycomb. Finally, the plugged green or calcined ceramic honeycomb is heated to a temperature sufficient to sinter the plugged green ceramic honeycomb to form a porous sintered plugged ceramic honeycomb. The method is particularly useful for simultaneously making the plugs and discriminating layers in the channels. In particular the method is useful to make wall-flow filters having plugs on at least one end with same composition as the discriminating layer or plugs on each end having different compositions. |