JP2748389B2 - High strength colored zirconia sintered body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a colored high-strength zirconia-based sintered body that can be used, for example, for shoes, tires and other anti-slip spikes.

[Conventional technology]

Hereinafter, a ceramic spike for tires will be described as an example, but the same applies to uses, particularly sports.

Conventionally, as a spike for snow tires on snow and ice, as shown in FIGS. 4 and 5, a steel shank 1 is used.
A pin 2 made of cemented carbide or a ring 3 made of cemented carbide
Are joined by a method such as brazing or caulking.

[Problems to be solved by the invention]

However, spikes made by the above method are expensive because they use cemented carbide for the pins and rings. Also,
It has been pointed out that disadvantages such as high fuel consumption due to its heavy weight, loud noise, and heavy damage to the road surface. As one method for solving the above-mentioned drawbacks of using pins and rings made of cemented carbide, the use of alumina-based ceramics instead of cemented carbide has been studied in recent years. However, since alumina-based ceramics have low toughness, there is a high risk of causing accidents such as breakage and breakage, and the ceramics have not been put to practical use.

Furthermore, zirconia ceramics have been studied because of their high toughness among ceramics, but this study is not yet sufficient. By the way, conventional zirconia-based ceramics are white or black, but as a recent trend, these spikes are required to have decorative properties. However, under the above-mentioned situation, colored zirconia-based ceramics have not yet been put to practical use.

An object of the present invention is to provide a high-strength colored zirconia-based sintered body that can be put to practical use and that solves the disadvantages of conventional products in view of such circumstances.

[Means and actions for solving the problem]

ZrO ₂ has a tetragonal monoclinic transition at around 1100 ° C., which causes difficulties in production, such as cracking during sintering.
By adding an appropriate amount of Y ₂ O ₃ to ZrO ₂ ,
It is known that most of ZrO ₂ is made to be tetragonal to solve the above-mentioned problem of crack generation during sintering and to increase the strength (Reference: J. Mat. Sci. 15 (1980) 2861) ~ 28).

The present inventors have focused on the above facts and as a result of research, 1.5
And a ZrO ₂ 72-94.9 wt% containing 5 mol% of Y ₂ O ₃ and / or 5 to 30 mol% of CeO _2, and the Al ₂ O ₃ 5 to 25 wt%, Cr, Er, Eo , Ho, Pr, Nd, Co, Ce, Tm and Th, obtained by sintering a composition comprising 0.1 to 3% by weight of one or more selected from the group consisting of 95% of the theoretical specific gravity calculated from the composition. %
A high-strength colored zirconia-based sintered body having a transverse rupture force of 160 kg / mm ² or more having the above specific gravity has been found to obtain the best properties as a colored ceramic for spikes, which has solved the conventional problems. It was.

The reason why the amount of Y ₂ O ₃ added to ZrO ₂ is limited to the range of 1.5 to 5 mol% and the content of CeO ₂ is limited to the range of 5 to 30 mol% is that Y ₂ O ₃ and / or Ce
If O ₂ is less than the lower limit of the above range, the metastable tetragonal crystallization is insufficient and defects such as crack generation at the time of production are not eliminated, and if it exceeds the upper limit, the appearance amount of cubic crystals increases This is because the strength is reduced.

When Al ₂ O ₃ is contained in the range of 5% by weight or more and 25% by weight or less, if less than 5%, the strength is not improved by the addition.
If the content exceeds 25% by weight, the strength is rather reduced.

Also, one or more selected from the group consisting of Cr, Er, Eu, Ho, Pr, Nd, Co, Ce, Tm and Th is contained in the sintered body at 0.1 to 3% by weight. If the content exceeds 3% by weight, the sinterability is impaired and the strength is greatly reduced.

For colored spikes, the zirconia-based sintered body has a theoretical specific gravity of 95% or more (calculated according to the composite rule of the specific gravity of the compound to be mixed), and the zirconia crystal phase is mainly tetragonal or It has been found that those satisfying the condition of tetragonal and cubic have sufficiently good strength properties and can be put to practical use. If the theoretical specific gravity is less than 95%, the bending strength is low and the spike performance is not good.

Although the effects of improving the decorativeness and the commercial value by coloring according to the present invention are clear, an example of an embodiment used as a spike for a snow tire will be described below with reference to the drawings to explain the function and effect of the present invention in terms of performance.

First, the spikes formed of the conventional ceramics alone have a low toughness as described above, and therefore, there is a high risk that the flanges will be damaged by impact on the flanges when driven into a tire. Therefore, in the conventional ceramic spike as shown in FIG. 4 or FIG. 5, in order to prevent this, it is necessary to protect the flange by coating the surface of the flange with plastic or the like. is the current situation.

On the other hand, in the case of a spike having a relatively high toughness than Al ₂ O ₃ as in the present invention and using a colored zirconia sintered body as a material, there is little risk of breakage even when driving into a tire. Therefore, as shown in FIG. 1, the entire spike 11 including the flange portion 12 can be formed by the zirconia-based sintered body alone. Further, as another embodiment, as shown in FIG. 2, one or more grooves 13 are provided near the mounting end of the spike 11, or
As shown in the figure, one or more holes 14 are provided to provide a retaining effect, and these portions may be surrounded by a plastic flange 15. In such a case, since the thickness of the plastic portion can be made larger than that of the stopper by the projection, the effect of the stopper can be further increased. Furthermore, since the volume of the spike portion is reduced, the weight can be further reduced. Processing such grooves or holes in these zirconia sintered body spikes is easy if the zirconia sintered body is intermediately sintered. On the other hand, in the case of the ceramics conventionally studied, since the toughness is low, if a groove or a hole is provided in one part, stress concentration may occur and the part may be broken, so that the flange part may be made of plastic. Even if it is surrounded by, its resistance is not good.

As described above, by using a zirconia sintered body as a material as in the present invention, a spike for a snow tire having high strength and a small weight can be obtained with high practical value. In the present invention, in order to provide a groove or a hole near the mounting end of a spike body made of a zirconia sintered body and to join a plastic flange to that portion, a synthetic resin is used by using the flange forming die. Is injected, whereby the synthetic resin is embedded in the grooves and holes, and the effect of preventing the flange portion from coming off can be achieved.

Although the description of the present invention has been made with respect to a ceramic spike for a tire, the ceramic spike of the present invention is not limited to a tire, but has the same effect as a spike for a tire, and is included in the present invention. Is what is done.

〔Example〕

A sintered body having a composition containing various metals shown in Table 1 was sintered to produce spikes having the shape shown in FIG.
m ² ), fracture toughness The spike performance was tested. The test results are also shown in Table 1. The spike performance was evaluated as good (indicated by a circle) if there were no cracks or defects.

The spikes were prepared by mixing the raw material powders having the compositions shown in Table 1 with a ball mill, granulating them with a spray drier, and then pressing them into spikes having the shape shown in FIG.
Sintering was performed at 1500 ° C., followed by HIP at 1000 ° C. and 1000 atm for 2 hours, followed by heat treatment at 1450 ° C. for 2 hours in the air. From these results, it can be seen that the colored zirconia sintered body of the present invention has properties that can withstand spikes sufficiently.

[Effects of the Invention] The high-strength colored zirconia sintered body of the present invention has high toughness and high transverse rupture strength, high strength, light weight, and coloring and decorativeness. Therefore, the present invention is industrially advantageous as a sintered body that can exhibit extremely excellent properties and commercial value when used for spikes and the like, and is open to practical use.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a spike of the present invention, FIGS. 2 and 3 are longitudinal sectional views showing another embodiment of the same, and FIG. 4 is a conventional carbide pin. FIG. 5 is a longitudinal sectional view of a conventional carbide ring type spike.

Claims (1)

(57) [Claims] (1) 1.5 to 5 mol% of Y ₂ O ₃ and / or 5 to 3
72 to 94.9% by weight of ZrO ₂ containing 0 mol% of CeO ₂ and Al ₂
O ₃ is 5 to 25% by weight, and one or more selected from Cr, Er, Eu, Ho, Pr, Nd, Co, Ce, Tm and Th is 0.1 to 3% by weight.
A high-strength colored zirconia-based sintered body having a specific gravity of 95% or more of the theoretical specific gravity calculated from said composition and having a transverse rupture force of 160 kg / mm ² or more.