| abstract |
Wall flow monolithic honeycomb filter having including microcracks having an average width less than 0.4 μm, and pores having a mean pore size in the range of 10 μm to 25 μm; and a washcoat disposed within the walls of the wall flow monolith, the washcoat including catalyst comprising support particles and at least one precious metal, where at least 90% of the support particles have particle sizes greater than the average size of the microcracks and at least 90% of the support particles have particle sizes less than the mean size of the pores of the wall flow monolith. The wall flow monolith comprises aluminum titanate having a porosity in the range of 40%. to 70%, wherein the soot filter shall exhibit a coefficient of thermal expansion less than 25 x 10-7/K when measured at 1000°C preferably less than 5 x 10-7/K when measured at 800 °C. |