Ceramic honeycomb structure and its production method
A ceramic honeycomb structure comprising pluralities of honeycomb segments each having pluralities of longitudinally penetrating flow paths partitioned by porous cell walls and plugs formed in the end portions of the flow paths, and a bonding material layer boding the peripheral walls of the honeycomb segments, the bonding material layer comprising silicon carbide particles as aggregate and a bonding phase bonding the silicon carbide particles, the bonding phase comprising at least a cordierite phase and a spinel phase, the molar ratio M1 of the cordierite phase [=cordierite phase/(cordierite phase+spinel phase)] being 0.50 or more and less than 1.0, and the content of (cordierite phase+spinel phase) in the bonding phase being 50% or more by mass.
1 . A ceramic honeycomb structure comprising pluralities of honeycomb segments each having pluralities of longitudinally penetrating flow paths partitioned by porous cell walls and plugs formed in the end portions of said flow paths, and a bonding material layer boding the peripheral walls of said honeycomb segments,
said bonding material layer comprising silicon carbide particles as aggregate, and a bonding phase bonding said silicon carbide particles,
said bonding phase comprising at least a cordierite phase and a spinel phase,
the molar ratio M1 of said cordierite phase [=cordierite phase/(cordierite phase+spinel phase)] being 0.50 or more and less than 1.0, and
the content of (cordierite phase+spinel phase) in said bonding phase being 50% or more by mass.
2 . The ceramic honeycomb structure according to claim 1 , wherein said bonding phase further comprises at least one selected from the group consisting of cristobalite, mullite and forsterite.
3 . The ceramic honeycomb structure according to claim 1 , wherein the thermal conductivity of said bonding material layer is 0.1-4.0 W/m·K.
4 . The ceramic honeycomb structure according to claim 1 , wherein the porosity of said bonding material layer is 50-70%.
5 . A method for producing the ceramic honeycomb structure according to claim 1 , comprising
mixing 100 parts by mass of silicon carbide particles with a binder comprising 5-25 parts by mass in total of alumina source particles and magnesia source particles, and an organic binder,
blending the resultant mixture with water to obtain a slurry,
applying said slurry to the peripheral walls of said honeycomb segments,
bonding the peripheral walls of said honeycomb segments to each other,
drying the bonded honeycomb segments, and
sintering the bonded honeycomb segments in a range of 1100-1350° C. in the air.
6 . The method for producing a ceramic honeycomb structure according to claim 5 , wherein said binder further comprises an inorganic binder.
7 . The method for producing a ceramic honeycomb structure according to claim 6 , wherein said inorganic binder is colloidal silica and/or colloidal alumina.
8 . The method for producing a ceramic honeycomb structure according to claim 5 , wherein said binder further comprises a pore-forming material.
9 . The method for producing a ceramic honeycomb structure according to claim 5 , wherein said binder further comprises at least one selected from the group consisting of spinel particles, mullite particles and forsterite particles.
10 . The method for producing a ceramic honeycomb structure according to claim 5 , wherein said alumina source particles and said magnesia source particles are mixed at a molar ratio M2 [=(Al 2 O 3 )/(Al 2 O 3 +MgO)] of 0.30-0.60.
11 . The method for producing a ceramic honeycomb structure according to claim 5 , wherein in said binder, the alumina source particles are alumina particles or aluminum hydroxide particles, and the magnesia source particles are magnesium oxide particles or magnesium hydroxide particles.
12 . The method for producing a ceramic honeycomb structure according to claim 5 , wherein said silicon carbide particles have a ratio D90/D10 of 1 or more and less than 10, wherein D10 represents a particle diameter at a cumulative particle volume corresponding to 10% of the total particle volume, and D90 represents a particle diameter at a cumulative particle volume corresponding to 90% of the total particle volume, in a curve showing the relation between particle diameter and cumulative particle volume.