Method of making diesel particulate filters

A method of making a porous cordierite article comprising the steps of:

• blending graphite, water insoluble cellulose, and
• ceramic-forming precursors in amounts suitable to form an cordierite forming precursors in amounts suitable to form an analytical batch composition by weight on an oxide basis of 9-20% MgO, 30-50% Al.sub.2 O.sub.3, and 41-56.6% SiO.sub.2, with an effective amount of vehicle and forming aids to form a plastic mixture;
• anisostatically extruding said plastic mixture through a die to form a green honeycomb, having a matrix of thin wall defining a multiplicity of open ended cells extending along longitudinal axes from one end to another end of said honeycomb and said thin walls having a substantially smaller coefficient of thermal expansion in a direction parallel to said longitudinal axes of said open ended cells than transverse to said thin walls;
• drying dielectrically said green honeycomb;
• and
• firing said dried green honeycomb under conditions effective to form said porous cordierite article consisting essentially of cordierite, wherein said graphite and said water insoluble cellulose are blended with said cordierite-forming precursors, said vehicle, and said forming aids in an amount effective to achieve an overall porosity of about 45 to about 55% in said porous cordierite article and to permit said drying to occur with substantially no arcing or shorting.

A method of making a diesel particulate filter, comprising the steps of:

• blending graphite, water insoluble cellulose, and cordierite-forming precursor in amounts suitable to form an analytical batch composition by weight on an oxide basis of 9-20% MgO, 30-50%, Al.sub.2 O.sub.3, and 41-56.5% SiO.sub.2 with an effective amount of vehicle and forming aids to form a plastic mixture;
• anisostatically extruding said plastic mixture through a die to form a green honeycomb, having a matrix of thin walls defining a multiplicity of open ended cells extending along longitudinal axes from a first end to a second end of said honeycomb and said thin walls having a substantially smaller coefficient of thermal expansion in a direction parallel to said longitudinal axes of said open ended cells than transverse to said thin walls;
• drying dielectrically said green honeycomb;
• firing said dried green honeycomb under conditions effective to form a ceramic article consisting essentially of cordierite, wherein said graphite and said water insoluble cellulose are blended with said cordierite-forming precursors, said vehicle, and said forming aids in an amount effective to achieve an overall porosity of about 45 to about 55% in said ceramic article and to permit said drying to occur with substantially no arcing or shorting;
• plugging alternate cells in a checkered style pattern such that cells closed at said first end are open at said second end;
• and
• refiring said ceramic article to form said diesel particulate filter.