# US 11,993,545 B2 · Silicon carbide ceramic honeycomb structure and its production method

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- Number: US 11,993,545 B2
- Document ID: US11993545B2
- Status: Granted
- Kind: B2
- Application number: 18/037,677
- Filed: 2022-03-23
- Published: 2024-02-01
- Granted: 2024-05-28
- Earliest claimed: 2021-03-26
- Assignees: Proterial, Ltd.
- Applicants: Proterial, Ltd.
- Inventors: Kenichiro Shimizu
- Web page: https://patentgrep.com/patent/US11993545B2

## CPC

- C04B 35/565: based on silicon carbide
- B01D 39/2075: {sintered or bonded by inorganic agents}
- B01D 46/2429: {of the honeycomb walls or cells}
- B01D 46/24491: {Porosity}
- B01D 46/2474: {of the walls along the length of the honeycomb}
- B01J 35/57: Honeycombs
- C04B 35/6303: {Inorganic additives}
- C04B 35/638: Removal thereof
- C04B 38/0006: {Honeycomb structures (from one or more corrugated sheets by winding or stacking C04B38/0083)}
- C04B 38/0009: {characterised by features relating to the cell walls, e.g. wall thickness or distribution of pores in the walls}
- C04B 38/0054: {the pores being microsized or nanosized}
- C04B 38/0074: {expressed as porosity percentage}
- F01N 3/0222: {the structure being monolithic, e.g. honeycombs}
- B01D 2239/10: Filtering material manufacturing
- B01D 2239/1208: Porosity
- B01D 2239/1216: Pore size
- B01D 2239/1241: Particle diameter
- C04B 2111/00413: {Materials having an inhomogeneous concentration of ingredients or irregular properties in different layers}
- C04B 2111/00793: {as filters or diaphragms}
- C04B 2235/3206: Magnesium oxides or oxide-forming salts thereof
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3826: Silicon carbides
- C04B 2235/5436: micrometer sized, i.e. from 1 to 100 micron
- C04B 2235/5463: Particle size distributions
- C04B 2235/5481: Monomodal
- C04B 2235/6021: Extrusion moulding
- C04B 2235/606: Drying
- C04B 2235/6567: Treatment time
- C04B 2235/6583: Oxygen containing atmosphere, e.g. with changing oxygen pressures
- C04B 2235/77: Density
- C04B 2235/9607: Thermal properties, e.g. thermal expansion coefficient
- F01N 2330/06: Ceramic, e.g. monoliths
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)

## Abstract

A silicon carbide ceramic honeycomb structure having large numbers of axially penetrating flow paths partitioned by porous silicon carbide cell walls, the cell walls having porosity of 35-50% and a median pore diameter of 8-18 μm, when a straight line C is drawn in parallel with the cell wall surface such that it passes a center in the direction of the thickness T of the cell wall, and straight lines are drawn in parallel with the straight line C such that they are separate from the straight line C by ±T/5 and ±2T/5 in the thickness direction of the cell wall, to measure the lengths (pore widths) of pore portions crossing each straight line, and the number of pores crossing each straight line, in a cell wall cross section perpendicular to the axial direction, an average pore width W determined by averaging the lengths (pore widths) of all measured pore portions being 10-25 μm, and the number N of pores per length determined by dividing the total number of the measured pores by the total length of the straight lines used for measurement being 20-40/mm.

## Claims

### Claim 1

A silicon carbide ceramic honeycomb structure having large numbers of axially penetrating flow paths partitioned by porous silicon carbide cell walls,
said silicon carbide ceramic honeycomb structure being composed of a sintered body of ceramic particles comprising aggregate and a binder,
said binder being at least one selected from the group consisting of alumina particles, aluminum hydroxide particles, magnesium oxide particles, and magnesium hydroxide particles,
said cell walls having porosity of 40-50% and a median pore diameter of 8-18 μm, and
when a straight line C is drawn in parallel with the cell wall surface such that it passes a center in the direction of the thickness T of said cell wall, and straight lines are drawn in parallel with said straight line C such that they are separate from said straight line C by ±T/5 and ±2T/5 in the thickness direction of said cell wall, to measure the lengths (pore widths) of pore portions crossing each straight line, and the number of pores crossing each straight line, in a cell wall cross section perpendicular to the axial direction,
an average pore width W determined by averaging the lengths (pore widths) of all measured pore portions being 10-25 μm,
the number N of pores per length determined by dividing the total number of the measured pores by the total length of the straight lines used for measurement being 20-40/mm,
the volume of pores having pore diameters of 20 μm or more being 10-20% of the total pore volume in said cell walls, and the volume of pores having pore diameters of 9 μm or less being 3-25% of the total pore volume in said cell walls, in the relation between the pore diameter and cumulative pore volume of said cell walls measured by mercury porosimetry.

### Claim 2 (depends on 1)

A method for producing the silicon carbide ceramic honeycomb structure according to claim 1, comprising formulating, mixing and blending ceramic particles comprising aggregate and a binder with an organic binder to form a moldable material, extrusion-molding said moldable material to a honeycomb shape, and drying and then sintering the resultant green body,
said aggregate being silicon carbide particles,
said binder being at least one selected from the group consisting of alumina particles, aluminum hydroxide particles, magnesium oxide particles and magnesium hydroxide particles,
said ceramic particles having a median particle diameter D50 of 37-45 μm, and
in a curve showing the relation between particle diameter and cumulative particle volume,
the particle diameter D10 at a cumulative particle volume corresponding to 10% of the total particle volume being 5-20 μm,
the particle diameter D90 at a cumulative particle volume corresponding to 90% of the total particle volume being 52-65 μm, and
the particle size distribution deviation SD being 0.20-0.40, wherein SD=log(D80)−log(D20), D20 is a particle diameter at a cumulative particle volume corresponding to 20% of the total particle volume, D80 is a particle diameter at a cumulative particle volume corresponding to 80% of the total particle volume, and D20<D80.