JPH0717445B2 - Zirconia black spike and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a zirconia-based black spike and a method for producing the same. More specifically, it relates to, for example, shoes, tires and other non-slip black spikes and a method for producing the same, and more particularly to a black zirconia spike having high practicality as a spike and a method for producing the same.

(Prior Art) Zirconia ceramics has been used as a high temperature water resistant material for a long time, but during sintering due to the volume change accompanying the crystal transition of high temperature type (tetragonal system) and low temperature type (monoclinic system). It is known to cause self-destruction. So in general
It was used as a stabilized zirconia ceramics (tetragonal ZrO ₂ ) that does not change in volume by adding oxides of metals such as Y, Ca and Mg as stabilizers. However, although this product is stable up to a considerably high temperature, its strength is low and it is difficult to obtain a dense sintered body. By the way, in the subsequent research, what was called partially stabilized zirconia (PSZ) or phase transformation strengthened zirconia (TTZ) was developed by studying the strength, toughness, and thermal shock resistance. It became almost satisfactory in various physical properties.

This partially stabilized zirconia composition has been attracting attention as a high-strength ceramic, and various applications have been developed. For example, scissors, slitters, and other blades can be used.

By the way, shoes, tires, and other anti-slip spikes, especially shoes, are required to have decorative properties and high strength materials. Conventionally, cemented carbide and cermet have been put to practical use. On the other hand, in the case of colored ceramics, in the black system, alumina ceramics with a pigment added (JP-A-56-59670), ruby, sapphire,
Natural or synthetic alumina-containing oxide single crystals such as emeralds are well known. These are final products obtained by cutting a single crystal material into a predetermined size with a diamond tool or the like, and performing various steps such as polishing and lapping.

However, these existing decorative ceramics are inferior in hardness and strength, especially in toughness, and it is not possible to freely select a color tone in a wide range, and moreover, a sophisticated technique is required to make a complicated shape, and the cost is low. It becomes high. In addition, although the black alumina ceramics described above are satisfactory in terms of color tone, they have problems such as breakage due to insufficient strength of the sintered body, and are still insufficient for practical use.

Therefore, it is conceivable to use the above partially stabilized zirconia, which is attracting attention as high-strength ceramics. However, since this partially stabilized zirconia originally has a white color, it is used as a black decorative material. Need to be colored.

As this coloring method, conventionally known is a method in which a stabilizer is added to a base material containing zirconia as a main component, which is molded and then formed in a non-oxidizing atmosphere. (JP-A-59-121165
(Problems to be solved by the invention) As described in detail above, high-strength partially stabilized zirconia has attracted attention as a decorative black ceramic material. It was white, and it was necessary to color it to obtain a black ornament.
As a method for blackening zirconia-based ceramics, the invention disclosed in JP-A-59-121165 is known.
With this method, it is not possible to obtain a product with a uniform color tone with good reproducibility, there are variations in the color tone from lot to lot, and there is the problem that it is broken due to insufficient strength as a spike material and it cannot be put to practical use. It was

Therefore, a problem to be solved by the present invention, in other words, an object of the present invention is to provide a zirconia-based spike having a high strength, a jet black color, and excellent decorative properties, and a method for producing the spike.

(Means for Solving the Problems) In view of the above-mentioned current state of the zirconia ceramics-based coloring method, the present inventors have realized a jet black color tone with good reproducibility and, in addition, selected a high-strength material as a spike material. As a result of various studies for new development, the present invention product was found.

That is, it consists of ZrO ₂ containing 1.5 to 5 mol% of Y ₂ O ₃ and / or 5 to 30 mol% of CeO ₂ , and has a theoretical specific gravity of 98.5% or more calculated from the composition and constitutes a sintered body. The zirconia-based black spike is characterized in that the crystal phase of zirconia is mainly tetragonal, or tetragonal and cubic, and exhibits a black color.

Further, the production method of the present invention comprises molding ZrO ₂ powder containing 1.5 to 5 mol% Y ₂ O ₃ and / or 5 to 30 mol% CeO ₂ , and then sintering the powder in a vacuum atmosphere, Then, hot isostatic pressing is performed.

(Operation) In the method of the present invention, the powder mixture of zirconia and the stabilizer can be obtained from the predetermined stabilizer and zirconia by the coprecipitation method, or the stabilizer powder and the zirconia powder are simply obtained. It can also be obtained by uniform mixing. Furthermore, the hydrolysis method of metal alkoxide, which has recently been attracting attention as a method for synthesizing a uniform powder having a strict composition ratio, can be used. In this case, the alkyl group of the alkoxide group has a small number of carbon atoms. Is advantageous.

In the present invention, "molding ZrO ₂ powder" is not particularly limited,
Molded without binder, or regular wax,
When molding is carried out by adding a small amount of a binder such as liquid paraffin or PVA petrolatum, this is until the binder is heated and removed.

Here, the powder diameters of the zirconia powder and the stabilizer powder are not particularly limited, but it is advantageous to make them as small as possible in order to obtain a dense sintered body with few voids. For example, it is preferably about 2.0 μm or less.

Sintering of the formed raw material mixture is performed at 1300 ℃ under vacuum atmosphere.
Appropriate temperature range is ˜1700 ° C., preferably 1450 ° C. to 1650 ° C. That is, when the sintering temperature is 1300 ° C. or lower, the molded body is not sintered, and when the sintering temperature is higher than 1700 ° C., the strength, particularly the toughness of the obtained sintered body is deteriorated, which is not preferable. Therefore, it is desirable to carry out the sintering operation at a temperature within the above range.

Further, it is important to stabilize the black color tone by arranging the molded body on the carbon case during the sintering of the present invention and further embedding it in the carbon powder.

Further, in the present invention, the sintering time is not critical, and is not particularly limited as long as it is within the range in which sintering is sufficiently achieved.

In the method for producing a sintered body of the present invention, zirconia which is an essential component, a stabilizer, various known additives, such as silica, alumina, a sintering accelerator such as titania,
It is also possible to add in an amount that does not impair the intended effect.

After sintering, hot isostatic pressing is performed.

As this temperature condition, 1200 ℃ ~ 1600 ℃, preferably, 13
A range of 00 ° C to 1500 ° C is suitable. That is, below 1200 ° C, the specific gravity required for spikes was not reached, and at 1600
If the temperature exceeds ℃, the strength, especially the toughness, of the obtained sintered body deteriorates, which is not preferable. The atmosphere is argon gas.
It should be 100 atm or more, and a range up to 2000 atm is appropriate. When the pressure is less than 100 atm, the densification is not sufficiently carried out, and when it exceeds 2000 atm, the productivity of the equipment is low, and the above range is suitable.

(Example) An ordinary press binder was mixed with ZrO ₂ powder having a Y ₂ O ₃ content of 3 mol%, and granulated by a spray dryer. This powder was pressed into a spike shape and then heat-treated in the air at 800 ° C. to remove the binder. This compact was placed in a carbon case and sintered at 1400 ° C. for 2 hours in a vacuum atmosphere. Then, hot isostatic pressing was performed at 1850 ° C. under an atmosphere of 1000 atmospheres of argon. In this way I got a motorcycle.

Practical performance was evaluated using the obtained sintered body as a spike for shoes. Same as before the sintering process, sintering in the air 1450
The white spike obtained by carrying out the test at 2 ° C. for 2 hours was also evaluated in the same manner. At the same time, gray spikes of Al ₂ O ₃ system and Si ₃ N ₄ system were experimentally manufactured and compared.

The results of each of the above spikes are shown in Table 1.

(Effects of the Invention) As shown in Table 1, the zirconia-based black spikes produced by the manufacturing method of the present invention are conventional zirconia-based white spikes, Al.
Compared with ₂ O ₃ series white spikes and Si ₃ N ₄ series gray spikes, the transverse rupture strength is 2-3 times larger and the practical performance is far superior.

Claims (2)

[Claims] 1. 1.5 to 5 mol% Y ₂ O ₃ and / or 5 to 3
It consists of ZrO ₂ containing 0 mol% CeO _2, has a theoretical specific gravity of 98.5% or more calculated from the composition, and the crystal phase of zirconia constituting the sintered body is mainly tetragonal or tetragonal and cubic A zirconia-based black spike characterized by having a black color. 2. 1.5 to 5 mol% Y ₂ O ₃ and / or 5 to 3
It consists of ZrO ₂ containing 0 mol% CeO _2, has a theoretical specific gravity of 98.5% or more calculated from the composition, and the crystal phase of zirconia constituting the sintered body is mainly tetragonal or tetragonal and cubic In order to produce a black zirconia-based black spike having a black color, a ZrO ₂ powder containing 1.5 to 5 mol% Y ₂ O ₃ and / or 5 to 30 mol% CeO ₂ is molded and then vacuum atmosphere is applied. A method for producing a zirconia-based black spike, which comprises sintering below and then hot isostatic pressing.