A ceramic honeycomb structure having pluralities of flow paths partitioned by porous cell walls; (a) the cell walls having porosity of 50-60%; and (b) in a pore diameter distribution in the cell walls measured by mercury porosimetry, (i) pore diameters at cumulative pore volumes corresponding to particular percentages of the total pore volume being within specific ranges and having specific relationships; and (ii) the difference between a logarithm of the pore diameter at a cumulative pore volume corresponding to 20% of the total pore volume and a logarithm of the pore diameter at 80% being 0.39 or less, and its production method.

The present disclosure relates to porous ceramic compositions and porous ceramic articles, such as honeycomb structure bodies and porous ceramic filters. In various embodiments, a particulate filter is disclosed herein; in some of these embodiments, the particulate filter is a gasoline particulate filter (GPF) and is suitable for use with a gasoline engine and treating its exhaust, and in some of the embodiments, the particulate filter is a diesel particulate filter (DPF) and is suitable for use with a diesel engine and treating its exhaust.

Provided are a composite material that has lower volume resistivity in comparison with SiC, SiC—Si, and the like, which are materials for forming constituent elements of an EHC, has low temperature dependence of volume resistivity, and thus is able to form a constituent element of a high-performance EHC; an electrode film, an electrode terminal, and a honeycomb substrate that are constituent elements of an EHC formed with such composite material, and a method for producing them. The composite material contains MoSi.sub.2 and at least one of Si or SiC, and is a material for forming a constituent element of an electrically heated catalytic converter. An electrode film 2, an electrode terminal 3, and a substrate 1 are produced from such composite material.

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 ceramic separation membrane structure in which a zeolite separation membrane formed on a ceramic porous body is repaired, and a repair method thereof. In the ceramic separation membrane structure, a zeolite separation membrane is disposed on a ceramic porous body, and defects of the zeolite separation membrane are repaired by zeolite repaired portions containing zeolite of structure different from the structure of zeolite of the zeolite separation membrane. The zeolite separation membrane and the zeolite repaired portions are made of a hydrophobic zeolite having a ratio of SiO.sub.2/Al.sub.2O.sub.3=100 or more.

A ceramic honeycomb body having intersecting walls that form channels extending axially from a first end face to a second end face and plugs to seal the channels at least at one of the first end face and the second end face. The plugs include a first active component, such as a catalytically active component or a chemically active component, of the plug structure, wherein the intersecting walls comprise no first active component and optionally have a second active component of the wall structure or disposed on the walls. Included are methods of making the ceramic honeycomb body having plugs of the first active component and walls with no first active component.

In a porous body, a surface layer thickness Ts takes a relatively small value satisfying P≧0.54 Ts (formula (1)), the surface layer thickness Ts being derived by a microstructure analysis using the porous-body data that is prepared through three-dimensional scanning of a region including a surface (inflow plane 61) of the porous body. Here, P denotes a porosity [%] of the porous body, and 0%<P<100% and 0 μm<Ts are assumed. The surface layer thickness Ts is derived as a distance in a thickness direction (X direction) between a surface-layer region start plane 92 in which a straight-pore opening ratio becomes 98% or less for the first time and a surface-layer region end plane 93 in which the straight-pore opening ratio becomes 1% or less for the first time.

The method of predicting a formed body density includes: a correlation calculating step of obtaining the correlation between the formed body density of the formed body and the porosity of the fired body; and a formed body density predicting step including: in a case of preparing a kneaded material A from a ceramic raw material having substantially the same composition as a ceramic raw material used for preparing a kneaded material, preparing a formed body B by forming the kneaded material A, preparing a dried body C by drying the formed body B, and preparing a fired body D having a desired porosity by firing the dried body C, calculating a predicted value of the formed body density of the formed body B corresponding to the desired porosity of the fired body D using the correlation.

The manufacturing method of the plugged honeycomb structure includes a honeycomb structure forming step of forming a pillar-shaped honeycomb structure, and a plugging step of forming plugging portions in end portions of the cells of the honeycomb structure formed in the honeycomb structure forming step, and in the plugging step, there is performed a press pouring operation of pressing one end face of the honeycomb structure into a plugging slurry stored in a bottomed tubular container to pour, under pressure, the plugging slurry into the cells of the honeycomb structure, and as the plugging slurry of the plugging step, there is used a slurry in which a yield point viscosity of a viscous fluidity is 600 Pa.Math.s or more, a recovery viscosity is 300 Pa.Math.s or more, and a high shearing viscosity is 200 Pa.Math.s or less.

We describe an apparatus for controlling a thickness of a workpiece element, the apparatus comprising: a lapping machine having a lapping plate; and a holder to hold a workpiece element; wherein said holder comprises: a workpiece element mount to mount a workpiece element to be lapped such that a surface of said workpiece element lies substantially flush with a lower face of said holder; an adjustable actuator to controllably move said surface of said workpiece element so that it remains substantially flush or projects beyond said lower face of said holder during lapping; means for urging said holder towards said lapping plate; and a sensor for sensing a displacement of the workpiece element towards said lapping plate.