A method and system to dry crack-free and high strength skin including an inorganic binder of an average particle size (D.sub.50) in a range between 10 nm and 700 nm on a porous ceramic body. The method includes supporting the honeycomb body on an end face such that axial channels and outer periphery are substantially vertical. A gas is flowed past the honeycomb body substantially parallel to the axial channel direction, substantially equally around the outer periphery of the skin, to uniformly dry the skin to form a partially dried skin under mild conditions. Then the partially dried skin may be dried more severely resulting in rapidly dried crack-free and high strength skin.

The invention relates to a binder, which contains water glass and further a phosphate or a borate or both. The invention further relates to a method for constructing molds and cores layer by layer, the molds and cores comprising a construction material mixture, which at least comprises a refractory molding base material, and the binder. In order to produce the molds and cores layer by layer in 3-D printing, the refractory molding base material is applied layer by layer and is selectively printed with the binder layer by layer, and consequently a body corresponding to the molds or cores is constructed and the molds or cores are released after the unbonded construction material mixture has been removed.

A method for manufacturing a honeycomb structure, includes: a step of manufacturing a honeycomb formed body to manufacture a non-fired honeycomb formed body having volume of 7 L or more; a drying step of drying the manufactured non-fired honeycomb formed body to obtain a honeycomb dried body; and a firing step of firing the obtained honeycomb dried body to obtain a honeycomb structure. The drying step includes: an induction drying step to obtain a first dried honeycomb formed body by removing 20 to 80% of the entire water that the non-fired honeycomb formed body contained before drying, and a microwave drying step to obtain a honeycomb dried body by removing the residual water. The honeycomb dried body subjected to this microwave drying step is obtained by removing 90% or more of the entire water that the non-fired honeycomb formed body contained before drying.

A method for drying a honeycomb formed body, the honeycomb formed body being an unfired honeycomb formed body including a raw material composition containing a ceramic raw material and water, the method including: a dielectric drying process of obtaining a primary dried honeycomb formed body from which 30 to 70% of entire moisture contained in the unfired honeycomb formed body before the drying is removed by performing dielectric drying on the unfired honeycomb formed body while maintaining a temperature of a central portion of the unfired honeycomb formed body at 100° C. or less; and a microwave drying process of obtaining a honeycomb dried body from which residual moisture is removed by performing microwave drying on the primary dried honeycomb formed body obtained in the dielectric drying process.

Disclosed is a ceramic honeycomb structure comprising a honeycomb body and a multilayered outer layer formed of a thick core layer applied and rapidly dried and a thin clad layer dried more gently to form a crack free dual skin layer. The core layer may have properties that are closer to those of the ceramic honeycomb body in service than the clad layer that may provide a tough outer shell to withstand handling and assembly.

Systems and methods for drying skinned ceramic wares (10) using recycled microwave radiation are disclosed. The method includes irradiating wet skinned ceramic wares (10W) in a first applicator section (124W) with microwave radiation (212), wherein said irradiating (212) gives rise to reflected microwave radiation (212R). The method also includes capturing a portion of the reflected microwave radiation (212R) and irradiating a plurality of semi-dry skinned ceramic wares (105) in a second applicator section (124S) with the reflected microwave radiation (212R). Systems for carrying out the method are also disclosed.

A method and system to dry crack-free and high strength skin including an inorganic binder of an average particle size (D.sub.50) in a range between 10 nm and 700 nm on a porous ceramic body. The method includes supporting the honeycomb body on an end face such that axial channels and outer periphery are substantially vertical. A gas is flowed past the honeycomb body substantially parallel to the axial channel direction, substantially equally around the outer periphery of the skin, to uniformly dry the skin to form a partially dried skin under mild conditions. Then the partially dried skin may be dried more severely resulting in rapidly dried crack-free and high strength skin.

A plugged honeycomb structure in which in a cross section of a honeycomb structure body which is perpendicular to an extending direction of cells, inflow cells are disposed to surround an outflow cell, and the number of the inflow cells is larger than the number of the outflow cells, and the cross section has a plurality of intersecting portions of partition walls each defining the inflow cells which are adjacent to each other, and in 60% or more of a total number of the intersecting portions, a relation between a diameter (D.sub.1) of a circle inscribed in the intersecting portion and a diameter (D.sub.0) of a circle inscribed in the partition wall defining the inflow cell and the outflow cell which are adjacent to each other satisfies D.sub.1/(√2×D.sub.0)=1.20 to 1.80

A microwave drying method includes: an introduction step of disposing a honeycomb formed body while keeping an axis direction X of cells of the honeycomb formed body vertically and introducing the honeycomb formed body into a drying furnace capable of irradiating with microwaves; a reflector placing step of placing a microwave reflector having a function to reflect the microwaves above and/or below around the honeycomb formed body; and a microwave drying step of irradiating with the microwaves while controlling temperature of an inside of the honeycomb formed body by the microwave reflector so that any one of the end faces (e.g., end face) of the honeycomb formed body reaches 100° C. to dry the honeycomb formed body after the other part of the honeycomb formed body reaches 100° C.

A honeycomb structure has a pillar-shaped honeycomb structure body having porous partition walls which defines cells which forms a passage of liquid extended from an inflow end face toward an outflow end face, a circumferential wall arranged to surround a circumference of the partition walls. The honeycomb structure body has an outermost circumference cell structure including a complete cell arranged at the outermost circumference of the honeycomb structure body, a center cell structure formed by the cells arranged at a center part at an inner side to the outermost circumference cell structure, and a boundary wall arranged at a boundary part between the outermost circumference cell structure and the center cell structure. The outermost circumference cell structure and the center cell structure are formed as different structures to each other, and a thickness of the boundary wall is set to be thicker than a thickness of the circumferential wall.