# US 4,396,724 A · Ceramic composition

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- Number: US 4,396,724 A
- Document ID: US4396724A
- Status: Granted
- Kind: A
- Application number: 06/267,043
- Filed: 1981-05-26
- Granted: 1983-08-02
- Earliest claimed: 1981-05-26
- Assignees: General Electric Company
- Inventors: Stephen J. Burden
- Web page: https://patentgrep.com/patent/US4396724A

## CPC

- C04B 35/119: with 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

## Abstract

Improved ceramic compositions useful for cutting tools and the like are described. They are composed of an essentially homogeneous admixture of sintered powders of an aluminum oxide base material with other refractories including zirconium oxide, titanium oxide, hafnium oxide, titanium nitride, zirconium nitride, and tungsten or molybdenum carbide. In addition to their common and improved properties of hardness and strength, many of these compositions may be made by simple cold-pressing and sintering procedures. This avoids the known drawbacks of conventional hot press production.

## Claims

### Claim 1

In a ceramic composition comprising an essentially homogeneous admixture of sintered powders of an aluminum oxide base refractory material, the improvement wherein said composition additionally contains zirconium oxide and tungsten carbide in an amount sufficient to enhance wear resistance while permitting said powder to undergo pressureless sintering.

### Claim 2 (depends on 1)

The composition of claim 1 wherein the composition also includes titanium nitride.

### Claim 3 (depends on 2)

The composition of claim 2, wherein the zirconium oxide is present in an amount from 1 to 30% and titanium nitride is present in an amount from 1 to 30% by total weight.

### Claim 4 (depends on 3)

The composition of claim 3, further including titanium oxide in an amount from 1 to 15% by total weight.

### Claim 5 (depends on 1)

The composition of claim 1, wherein the tungsten carbide is present in amounts up to 5% by total weight.

### Claim 6 (depends on 1)

The composition of claim 1, wherein the powders are cold-pressed and then sintered.

### Claim 7 (depends on 1)

The composition of claim 1 wherein the composition also includes zirconium nitride.

### Claim 8 (depends on 2)

The composition of claim 2, wherein the titanium nitride is present in from 15 to 30% by total weight.

### Claim 9

In a ceramic composition comprising an essentially homogeneous admixture of sintered powders of an aluminum oxide base refractory material, the improvement wherein said composition additionally contains zirconium oxide, tungsten carbide, and titanium nitride, the aluminum oxide comprising from 67-87%, the zirconium oxide comprising 10-15%, the titanium nitride comprising 1-15% and the tungsten carbide comprising 2-3% by total weight.