Permeable material, articles made therefrom and method of manufacture

Abstract

The invention is directed to a honeycomb comprising cordierite and β-spudomene, the honeycomb having a having total porosity of greater than 30% and a mean pore diameter of less than 5 μm. The honeycomb is made from a mixture of activated kaolin and a mineral selected from the group consisting of lithium fluorhectorite, lithium hydroxyhectorite and mixtures thereof. In one embodiment up to 20 wt % weight SiO 2 , based on the total weight of the kaolin and minerals (fluorhectorite, hydroxyhectorite) is added and mixed therein prior to the formation of the green body. In another embodiment the amount of added SiO 2 is up to 10 wt %. In one embodiment the total porosity is greater than 50% and the mean pore diameter is less than 5 μm.

We claim: 
     
         1 . A honeycomb comprising cordierite and β-spodumene, said honeycomb having a total porosity greater than 30% and a mean pore diameter of less than 5 μm. 
     
     
         2 . The honeycomb according to  claim 1 , wherein the porosity is greater than 40%. 
     
     
         3 . The honeycomb according to  claim 1 , wherein the porosity is greater than 50%. 
     
     
         4 . The honeycomb according to  claim 1 , wherein said honeycomb has a CTE of less than 25×10 −7 /° C. over the temperature range of 22-1000° C. 
     
     
         5 . The honeycomb according to  claim 3 , wherein said honeycomb has a CTE of less than 25×10 −7 /° C. over the temperature range of 22-1000° C. 
     
     
         6 . The honeycomb according to  claim 1 , wherein the honeycomb has a CTE of less then 15×10 −7 /° C. over the temperature range of 22-1000° C. 
     
     
         7 . The honeycomb according to  claim 3 , wherein the honeycomb has a CTE of less then 15×10 −7 /° C. over the temperature range of 22-1000° C. 
     
     
         8 . A particulate filter comprising cordierite and β-spodumene, said particulate filter having a total porosity greater than 30%, and a mean pore diameter of less than 5 μm. 
     
     
         9 . The particulate filter according to  claim 8 , wherein the porosity is greater than 50%. 
     
     
         10 . The particulate filter according to  claim 8 , wherein the particulate filter has a CTE of less then 15×10 −7 /° C. over the temperature range of 22-1000° C. 
     
     
         11 . The particulate filter according to  claim 9 , wherein the particulate filter has a CTE of less then 15×10 −7 /° C. over the temperature range of 22-1000° C. 
     
     
         12 . A porous article comprising cordierite and β-spodumene, said article having a total porosity greater than 30% and a mean pore diameter of less than 5 μm.