# US 5,346,869 A · Sintered silicon nitride bodies suitable for use as high impact materials

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- Number: US 5,346,869 A
- Document ID: US5346869A
- Status: Granted
- Kind: A
- Application number: 08/175,490
- Filed: 1993-12-29
- Granted: 1994-09-13
- Earliest claimed: 1991-06-26
- Assignees: Sumitomo Electric Industries, Ltd.
- Inventors: Takao Nishioka; Takehisa Yamamoto; Kenji Matsunuma; Akira Yamakawa; Masaya Miyake
- Web page: https://patentgrep.com/patent/US5346869A

## CPC

- C04B 35/584: based on silicon nitride
- C04B 35/5935: {obtained by gas pressure sintering}
- C04B 35/597: based on silicon oxynitride, {e.g. SIALONS}
- F01L 1/205: {by means of shims or the like}
- F02F 7/0087: {Ceramic materials}
- F02B 3/06: with compression ignition (compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02)
- F05C 2203/0895: Zirconium oxide
- 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
- F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- 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

Described are sintered silicon nitride bodies useful as materials for parts required to have strength, especially excellent impact strength for items such as automobile parts and machine parts. The sintered Si.sub.3 N.sub.4 bodies contain 80-98 wt. % of silicon nitride and have a porosity not higher than 3% and an shock compressive elasticity limit of at least 15 GPa.

## Claims

### Claim 1

A sintered silicon nitride body suitable for use as a high impact material, comprising 80 to 98 wt % of silicon nitride and a sintering aid consisting of 1 to 10 wt % Y.sub.2 O.sub.3, 0.5 to 4.0 wt % Al.sub.2 O.sub.3, and 0.5 to 1.0 wt % MgO, said sintered silicon nitride body having a porosity not higher than 3%, a shock compressive elasticity limit (Hugonoit-elastic limit (HEL)) of at least 15 GPa, and a bending strength of at least 100 kg/mm.sup.2.