Patent ID: 7297299

Claim:
A method for selectively plugging channels of a ceramic honeycomb comprising: introducing into respective open transverse cross-sectional areas of selected channels a plastically shapeable cement composition consisting essentially of a blend of a ceramic powder, a water-soluble alkali metal silicate, water and, optionally, (i) a reactive salt of a multivalent cation selected from the group consisting of calcium, aluminum, manganese, magnesium, iron, zinc, nickel, chromium and copper, and (ii) calcium aluminate; and the ceramic powder comprising one or more powders selected from the group consisting of cordierite, clay, talc, alumina, spinel, silicon carbide, silicon nitride, aluminum titanate and mixtures thereof; and drying the cement composition to form solid plugs that seal respective transverse cross-sectional areas of the selected channels to provide a pattern of plugged channels.