JP2764177B2 - Manufacturing method of wear-resistant ceramics - Google Patents

Description

The present invention relates to a method for producing ceramics, particularly zirconia ceramics, alumina ceramics, and a zirconia / alumina composite ceramics with improved wear resistance.

b.Conventional technology Zirconia ceramics, alumina ceramics and zirconia / alumina composite ceramics have high strength and high toughness, and their wear resistance is superior to that of metal materials. ing.

On the other hand, in order to take advantage of ceramics, bonding of ceramics to metal, bonding of ceramics to ceramics, or compounding of ceramics surfaces by coating or the like has recently been performed.

c. Problems to be Solved by the Invention However, the above ceramics have low wear resistance and are unstable compared to ceramics such as SiC. And even if an attempt is made to form a film such as SiC with excellent abrasion resistance on the surface of such ceramics, the film will peel off due to thermal stress acting on the interface due to the large difference in thermal expansion between the two, resulting in a film with good adhesion. I couldn't.

Further, in the case of embedding particles, there is a problem that even if the thermal stress can be remarkably reduced, particles such as SiC are hard and damage the surface such as cracks.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of manufacturing a ceramic in which particles such as SiC are embedded in the surface of the ceramic to improve its wear resistance.

d. Means for Solving the Problems In accordance with the above object, the present invention plastically deforms at 1000 ° C or more,
Crystal grain size is 3μm or less in the ceramic surface, the coefficient of thermal expansion is to be the ceramic and equal to or less wear-resistant particles, embedded temperature 1000 to 1600 ° C., embedding a pressurized pressure stress 15 kg / mm ² or less Has solved the problem.

Hereinafter, the present invention will be described in detail with reference to the drawings.

First, a case where SiC particles are embedded in zirconia ceramics will be described.

The present invention makes use of the fact that zirconia ceramics are easily plastically deformed at a temperature of 1000 ° C. or more. At that temperature, pressure is applied as shown in FIGS. Etc. are embedded.

That is, in FIG. 1, 1 is a zirconia ceramic to be treated, 2 is a receiving die, 3 is a pressing die, and particles 4 such as SiC are interposed between the zirconia ceramics 1 and the receiving die 2. Apply pressure. FIG. 2 shows a case where the particles 4 are embedded in the side surface of the zirconia ceramics 1 in the same manner.

The zirconia ceramics 1 used in the present invention is partially stabilized by yttria, magnesia, ceria, etc., and has a crystal grain size of 3 μm or less, more preferably 2 μm or less. In other words, when the crystal grain size exceeds 3 μm, it is not suitable because plastic deformation does not easily occur even when pressure is applied, and cracks occur during pressurization.

The treatment is performed at a temperature of 1000 ° C. or more. Below this, plastic deformation does not occur easily. On the other hand, when the treatment temperature exceeds 1600 ° C., the growth of crystal grains becomes remarkable, which is not preferable. Therefore, the processing temperature for embedding is performed in the range of 1000 to 1600 ° C.

Next, the stress applied to the zirconia ceramics is 15 kg / mm ²
The following is assumed. If it is larger than this, cracks may occur during pressurization.

As particles embedded in the surface of zirconia ceramics
In addition to SiC, TiC, WC, B ₄ C and similar abrasive particles are used.

The thermal expansion coefficient of the embedded particles is preferably equal to or slightly smaller than that of zirconia ceramics. If the coefficient of thermal expansion is small, when cooling after embedding,
Compressive stress due to shrinkage of the surrounding zirconia ceramics acts on the embedded particles, and the particles are held firmly. If the coefficient of thermal expansion of the particles to be embedded is considerably larger than that of the zirconia ceramics, voids are likely to be formed around the particles by cooling, which is not preferable.

Alumina ceramics and zirconia / alumina composite ceramics may be treated under the same conditions and method.

In the case of zirconia / alumina composite ceramics, it is sintered by normal pressure sintering, hot pressing and hot isostatic pressing, and its crystal grain size is also preferably 3 μm or less, more preferably 2 μm or less. .

Example 1 SiC particles (average particle size: about 5 μm) were embedded in the surface of a partially stabilized zirconia disk (φ60 × 10 mm) containing 3 mol% yttria as a solid solution in the manner shown in FIG.
The press die and the receiving die are made of SiC and used in vacuum (5 × 10 ^-5 T
orr) at 1450 ° C. and 10 MPa for 10 minutes. The surface roughness before and after embedding the SiC particles was the same at Rmax3.2S.

In order to compare the abrasion resistance of the material treated in this way, a pin quenched with a hemispherical tip (φ6 × 20mm, SKD11)
Was pressed against the surface of the treated ceramic and rotated to perform a wear test. The pressing force of the pin was 1 kg, and the sliding speed was 20 cm / s.

As a result, the wear volume per unit sliding distance was 5 × 10 ⁻⁸ mm ³ / kg · m for the case where SiC particles were not embedded and 1 × 10 ⁻⁸ mm ³ / kg · m for the case where SiC particles were embedded.

Example 2 A pin (φ6 × 10 mm) treated in the same manner for a disc treated with alumina under the same conditions and in the same manner as in Example 1 above (however, the pressure was 30 MPa and the pressurizing time was 15 minutes)
As a result of a wear test, the wear volume was 1 × 10 ⁻⁸ mm ³ / kg · m without SiC particles embedded and 5 × 10 ⁻⁹ mm ³ / kg · m with SiC particles embedded.

Example 3 A disk of zirconia / alumina composite ceramics obtained by adding 20% by weight of alumina to zirconia in which 3 mol% of yttria was dissolved and sintering by hot isostatic pressing (HIP), under exactly the same conditions as in Example 1 above. (However, the pressurizing time is 15 minutes) and embedded SiC particles.

When a wear test was performed in the same manner, the wear volume of the sample without embedded SiC particles was 2 × 10 ⁻⁸ mm ³ / kg · m, and that of the sample with embedded SiC particles was 8 × 10 ⁻⁹ mm ³ / kg · m.

e. Effects of the Invention According to the method of the present invention, it is possible to improve the wear resistance of ceramics, especially zirconia ceramics, alumina ceramics, and zirconia / alumina composite ceramics, and the range of application as a structural material is greatly expanded. Therefore, the industrial use value is extremely large.

Further, according to the method of the present invention, since the particles are easily embedded in the ceramics by plastic deformation, damage to the surface to be embedded by hard particles such as SiC can be suppressed, and the embedding can be performed in a relatively short time, and the required pressure is small. Help me.

[Brief description of the drawings]

1 and 2 are views for explaining a method for producing a wear-resistant ceramic according to the present invention. 1. Ceramics, 4. Particles of SiC, etc.

Claims (3)

(57) [Claims] (1) plastic deformation at a temperature of 1000 ° C. or more and a crystal grain size of 3 μm;
m the following ceramic surface, the thermal expansion rate of the ceramic is equal to or smaller than the wear resistant particles, embedded temperature 1000 to 1600 ° C., abrasion resistance, characterized in that embedded in the pressurized pressure stress 15 kg / mm ² or less Manufacturing method of ceramics. 2. The method for producing a wear-resistant ceramic according to claim 1, wherein said ceramic is zirconia, alumina or a composite ceramic of zirconia / alumina. 3. The production of a wear-resistant ceramic according to claim 1, wherein the wear-resistant particles are SiC, TiC, WC, B ₄ C and other similar substances. Method.