A ceramic honeycomb filter has (a) cross section areas of intake flow paths being larger than those of discharge flow paths; (b) the intake and discharge flow paths having octagonal cross section shapes with four-fold rotation symmetry each obtained by cutting off four corners from a square; (c) the intake and discharge flow paths being alternately arranged in a first direction and a second direction perpendicular to the first direction, such that their opposing sides are parallel; (d) the opening ratio of the intake flow paths being 45-60%; (e) the number of the flow paths per cm.sup.2 being 30-60; (f) the thickness t1 of a cell wall between an intake flow path and a discharge flow path adjacent to that intake flow path being 0.150-0.260 mm; and (g) the thickness t2 of a cell wall between adjacent intake flow paths meeting 1.175<t2/t1<1.6.

A method for indirect additive manufacturing of an object constructed of boron carbide, silicon carbide, and free silicon, comprising: (i) producing a porous preform constructed of boron carbide and silicon carbide by an indirect ceramic additive manufacturing (ICAM) process in which particles of a powder mixture become bonded together with an organic binder, wherein the powder mixture comprises: a) boron carbide particles, and b) silicon carbide particles, wherein at least 80 vol % of the silicon carbide particles are larger than the boron carbide particles; and wherein the boron carbide and silicon carbide particles are each included in an amount of 40-60 wt. % of the powder mixture, provided that the foregoing amounts sum to at least 95 wt. %; (ii) subjecting the porous preform to a temperature of 500-900° C. to volatilize the organic binder; and (iii) infiltrating molten silicon into pores of the porous preform to produce the object.

A method for indirect additive manufacturing of an object constructed of boron carbide, silicon carbide, and free silicon, comprising: (i) producing a porous preform constructed of boron carbide and silicon carbide by an indirect ceramic additive manufacturing (ICAM) process in which particles of a powder mixture become bonded together with an organic binder, wherein the powder mixture comprises: a) boron carbide particles, and b) silicon carbide particles, wherein at least 80 vol % of the silicon carbide particles are larger than the boron carbide particles; and wherein the boron carbide and silicon carbide particles are each included in an amount of 40-60 wt. % of the powder mixture, provided that the foregoing amounts sum to at least 95 wt. %; (ii) subjecting the porous preform to a temperature of 500-900° C. to volatilize the organic binder; and (iii) infiltrating molten silicon into pores of the porous preform to produce the object.

A corrosion-resistant ceramic of the present disclosure contains aluminum oxide as a main component and a yttrium-aluminum composite oxide as a secondary component, and includes a plurality of open pores. When an average value of inter-centroid distances between adjacent open pores is denoted by L1, L1 is 50 μm or greater.

A corrosion-resistant ceramic of the present disclosure contains aluminum oxide as a main component and a yttrium-aluminum composite oxide as a secondary component, and includes a plurality of open pores. When an average value of inter-centroid distances between adjacent open pores is denoted by L1, L1 is 50 μm or greater.

Methods for engineered cellular magmatic usable as filter media and articles thereof are disclosed. For example, the magmatics may include one or more infiltration materials that are configured not to sinter when a foamed mass is formed. The infiltration materials may be enclosed in cells of the foamed mass and may be floating and/or fixed to the cell walls.

Methods for engineered cellular magmatic usable as filter media and articles thereof are disclosed. For example, the magmatics may include one or more infiltration materials that are configured not to sinter when a foamed mass is formed. The infiltration materials may be enclosed in cells of the foamed mass and may be floating and/or fixed to the cell walls.

A ceramic filter having a pillar-shaped honeycomb structure, wherein when observing a plurality of pores from a surface of partition walls with a laser microscope and plotting an equivalent circle diameter (μm) of each pore on an X-axis and a pore depth (μm) of each pore on a Y-axis on a two-dimensional coordinate system, a slope of a regression line (y/x) obtained by a least squares method in a range of 20≤x≤40 is 0 to 0.20, an average value of the pore depth of the plurality of pores is 2.5 μm to 5.0 μm, and a number density of the plurality of pores is 600/mm.sup.2 to 2450/mm.sup.2.

A ceramic filter having a pillar-shaped honeycomb structure, wherein when observing a plurality of pores from a surface of partition walls with a laser microscope and plotting an equivalent circle diameter (μm) of each pore on an X-axis and a pore depth (μm) of each pore on a Y-axis on a two-dimensional coordinate system, a slope of a regression line (y/x) obtained by a least squares method in a range of 20≤x≤40 is 0 to 0.20, an average value of the pore depth of the plurality of pores is 2.5 μm to 5.0 μm, and a number density of the plurality of pores is 600/mm.sup.2 to 2450/mm.sup.2.

A process for producing a porous alpha-alumina catalyst support, comprising i) preparing a precursor material comprising, based on inorganic solids content, at least 50 wt.-% of a transition alumina having a loose bulk density of at most 600 g/L, a pore volume of at least 0.6 mL/g and a median pore diameter of at least 15 nm; and at most 30 wt.-% of an alumina hydrate; ii) forming the precursor material into shaped bodies; and iii) calcining the shaped bodies to obtain the porous alpha-alumina catalyst support. The catalyst support has a high overall pore volume, thus allowing for impregnation with a high amount of silver, while keeping its surface area sufficiently large so as to provide optimal dispersion of catalytically active species, in particular metal species. The invention further relates to a shaped catalyst body for producing ethylene oxide by gas-phase oxidation of ethylene, comprising at least 15 wt.-% of silver, relative to the total weight of the catalyst, deposited on a porous alpha-alumina catalyst support obtained in the process described above. The invention also relates to a process for preparing a shaped catalyst body as described above comprising impregnating a porous alpha-alumina catalyst support obtained in the process described above with a silver impregnation solution, preferably under reduced pressure; and optionally subjecting the impregnated porous alumina support to drying; and b) subjecting the impregnated porous alpha-alumina support to a heat treatment; wherein steps a) and b) are optionally repeated. The invention further relates to a process for producing ethylene oxide by gas-phase oxidation of ethylene, comprising reacting ethylene and oxygen in the presence of a shaped catalyst body as described above.