# US 5,346,870 A · Aluminum titanate ceramic and process for producing the same

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,346,870 A
- Document ID: US5346870A
- Status: Granted
- Kind: A
- Application number: 07/933,222
- Filed: 1992-08-21
- Granted: 1994-09-13
- Earliest claimed: 1991-08-28
- Assignees: NGK Insulators, Ltd.
- Inventors: Yasushi Noguchi; Shinichi Miwa; Kaname Fukao
- Web page: https://patentgrep.com/patent/US5346870A

## CPC

- C04B 35/6263: {characterised by their solids loadings, i.e. the percentage of solids}
- C04B 35/478: based on aluminium titanates
- F02F 7/0087: {Ceramic materials}
- 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 2235/322: Transition aluminas, e.g. delta or gamma aluminas
- C04B 2235/3224: Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
- C04B 2235/3225: Yttrium oxide or oxide-forming salts thereof
- C04B 2235/3229: Cerium oxides or oxide-forming salts thereof
- C04B 2235/3232: Titanium oxides or titanates, e.g. rutile or anatase
- C04B 2235/3234: Titanates, not containing zirconia
- C04B 2235/3272: Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
- C04B 2235/3293: Tin oxides, stannates or oxide forming salts thereof, e.g. indium tin oxide [ITO]
- C04B 2235/3418: Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
- C04B 2235/3463: Alumino-silicates other than clay, e.g. mullite
- C04B 2235/349: Clays, e.g. bentonites, smectites such as montmorillonite, vermiculites or kaolines, e.g. illite, talc or sepiolite
- C04B 2235/36: Glass starting materials for making ceramics, e.g. silica glass
- C04B 2235/44: Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
- C04B 2235/442: Carbonates
- C04B 2235/443: Nitrates or nitrites
- C04B 2235/444: Halide containing anions, e.g. bromide, iodate, chlorite
- C04B 2235/448: Sulphates or sulphites
- C04B 2235/5436: micrometer sized, i.e. from 1 to 100 micron
- C04B 2235/5445: submicron sized, i.e. from 0,1 to 1 micron
- C04B 2235/656: characterised by specific heating conditions during heat treatment
- C04B 2235/80: Phases present in the sintered or melt-cast ceramic products other than the main phase
- C04B 2235/96: Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
- C04B 2235/9607: Thermal properties, e.g. thermal expansion coefficient
- F02B 1/04: with fuel-air mixture admission into cylinder
- F05C 2251/042: Expansivity
- 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
- F02F: CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F05C: INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES

## Abstract

An aluminum titanate ceramic has as main crystalline phases, a crystalline phase of aluminum titanate and a solid solution thereof, a crystalline phase of mullite and a crystalline phase of rare earth titanate represented by RE.sub.2 Ti.sub.2 O.sub.7 (RE represents Y, Yb, Er, Dy, Ho, Tm or Lu). The aluminum titanate ceramic is superior in casting property and has high heat cycle durability.

## Claims

### Claim 1

An aluminum titanate ceramic comprising:
40-60% by weight of Al.sub.2 O.sub.3, 30-45% by weight of TiO.sub.2, 1-10% by weight of SiO.sub.2, 0-4% by weight of Fe.sub.2 O.sub.3, 0.1-1.5% by weight of MgO and 0.1-10% by weight of RE.sub.2 O.sub.3, where RE represents Y, Yb, Er, Dy, Ho, Tm or Lu;
in the form of a crystalline phase of aluminum titanate and a solid solution thereof, a crystalline phase of mullite and a crystalline phase of rare earth titanate represented by RE.sub.2 Ti.sub.2 O.sub.7.

### Claim 2 (depends on 1)

An aluminum titanate ceramic according to claim 1, further comprising at least one crystalline phase of the ceramic selected from rutile and corundum.

### Claim 3

A process for producing an aluminum titanate which comprises preparing a plurality of raw material powders of 5 .mu.m or less in average particle diameter, consisting essentially of an Al.sub.2 O.sub.3 source, a TiO.sub.2 source, an SiO.sub.2 source, an Fe.sub.2 O.sub.3 source, an MgO source, a rare earth element source, a mullite source and Al.sub.2 TiO.sub.5 source,
mixing the raw material powders to obtain a mixture,
shaping the mixture to obtain a shaped body,
drying the shaped body to obtain a dried body and then sintering the dried body to obtain an aluminum titanate ceramic comprising 40-60% by weight of Al.sub.2 O.sub.3, 30-45% by weight of TiO.sub.2, 1-10% by weight of SiO.sub.2, 0-4% by weight of Fe.sub.2 O.sub.3, 0.1-1.5% by weight of MgO and 0.1-10% by weight of RE.sub.2 O.sub.3, where RE represents Y, Tb, Er, Dy, Ho, Tm or Lu, in the form of a crystalline phase of aluminum titanate and a solid solution thereof, a crystalline phase of mullite and a crystalline phase of rare earth titanate represented by RE.sub.2 Ti.sub.2 O.sub.7.

### Claim 4 (depends on 3)

A process for producing an aluminum titanate according to claim 3, wherein the raw materials contain the Al.sub.2 TiO.sub.5 source in an amount of 5% by weight or more based on all the raw materials.

### Claim 5 (depends on 3)

A process for producing an aluminum titanate according to claim 3, wherein the raw materials contain the Al.sub.2 TiO.sub.5 source in an amount of 20% by weight or more based on all the raw materials.