Honeycomb structural body for exhaust gas purification

Abstract

A honeycomb structural body and a method for the manufacturing thereof. The manufacturing method includes (i) providing a plurality of silicon carbide honeycomb segments, each having a cell structure and at least one outer wall; (ii) subjecting the honeycomb segments to an oxidizing therman treatment forming a surface layer of silicon oxides on the at least one outer wall; and (iii) bonding the plurality of oxidized honeycomb segments so as to form the honeycomb structural body in the substantial absence of organic binders with the interposition of a sealing material including a mixture of one or more silicon carbide powders, one or more ceramic fibers, and one or more inorganic binders.

1 - 27 . (canceled) 
     
     
         28 . A honeycomb structural body comprising a plurality of honeycomb segments each having a cell structure and at least one outer wall, wherein said honeycomb segments are bonded to each other at the outer walls by the interposition of a sealing layer cooperating with a surface layer of silicon oxides formed on said outer walls, wherein said sealing layer comprises a sealing material consisting of a mixture of one or more silicon carbide powders, one or more ceramic fibers, and one or more inorganic binders, and wherein said sealing material is substantially free of organic binders, and wherein the one or more ceramic fibers have a length of about 0.5 to about 50 mm. 
     
     
         29 . The honeycomb structural body according to  claim 28 , wherein said layer of silicon oxides has a thickness of 0.001 μm to 10 μm. 
     
     
         30 . The honeycomb structural body according to  claim 28 , wherein said silicon oxides are selected from amorphous and crystalline SiO 2 , and SiO, and mixtures thereof. 
     
     
         31 . The honeycomb structural body according to  claim 28 , wherein said honeycomb structural body comprises 2 to 10 honeycomb segments. 
     
     
         32 . The honeycomb structural body according to  claim 31 , wherein said honeycomb structural body comprises 4 to 8 honeycomb segments. 
     
     
         33 . The honeycomb structural body according to  claim 28 , wherein a coating layer is applied on the outer peripheral portion of said honeycomb structural body. 
     
     
         34 . The honeycomb structural body according to  claim 28 , wherein said silicon carbide powder has an average particle diameter lower than 10 μm. 
     
     
         35 . The honeycomb structural body according to  claim 28 , wherein said silicon carbide powder is present in an amount of about 20% to about 80% by weight of said sealing material. 
     
     
         36 . The honeycomb structural body according to  claim 28 , wherein said ceramic fiber is selected from alkaline and alkaline earth silicate fibers. 
     
     
         37 . The honeycomb structural body according to  claim 28 , wherein said ceramic fiber is present in an amount of about 5% to about 50% by weight of said sealing material. 
     
     
         38 . The honeycomb structural body according to  claim 28 , wherein said inorganic binder is selected from alumina sol, silica sol, titania sol, water glass and mixtures thereof. 
     
     
         39 . The honeycomb structural body according to  claim 28 , wherein said inorganic binder is present in an amount of about 1 to about 20% by weight of said sealing material. 
     
     
         40 . The honeycomb structural body according to  claim 28 , wherein said sealing layer has a thickness of 0.1 to 8 mm. 
     
     
         41 . The honeycomb structural body according to  claim 28 , wherein said one or more ceramic fibers are selected from the group consisting of alumino-silicate fibers, silica-alumina fibers, mullite fibers, alumina fibers, silicate fibers, alkaline earth silicate fibers, basalt rock wool fibers, and fiberglass fibers.