JPH09208295A - Wear resistant alumina ornamental member and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain colored alumina ceramics having high ornamental property and superior wear resistance. SOLUTION: This ornamental member is made of alumina ceramics based on alumina and contg. <=0.2wt.% magnesium oxide and/or silicon oxide and 0.005-0.1wt.% one or more kinds of metals selected from among Co, Ni, Cr, Mn and V as coloring components. The intensity ratio (I/I0 ) of the 1st peak intensity (I) of crystals of oxides of the coloring components to the 1st peak intensity (I0 ) of alumina crystals in the sintered compact is <0.02.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wear-resistant alumina decorative member used as a guide member such as a fishing line guide and a fiber guide, a watch case and other parts for a watch, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, guide members such as fishing line guides and fiber guides, watch cases and other parts for timepieces are required to have high wear resistance as well as decorativeness.

For example, carbon steel having a hard chrome plating at least on its sliding surface with a line has been used for a guide member such as a fishing line guide or a fiber guide. However, in such a guide member, as the thread slides at a high speed, the plating on the sliding surface is likely to be peeled off, causing wear in a short period of time, and there is a problem in terms of corrosion resistance.

Therefore, in recent years, guide members formed of colored alumina ceramics have been used.

As this kind of alumina ceramics,
Powder such as magnesium oxide is added as a sintering aid to alumina powder, and powder of oxide such as cobalt, nickel, chromium, manganese is added as a coloring pigment in an amount of about 0.1 to 10% by weight and mixed. Make granules,
Some of them are formed by filling a mold and molding it into a predetermined shape, followed by firing in a reducing atmosphere (JP-A-56-140070 and JP-A-56-140071).
JP-A-62-224226).

[0006]

However, in the alumina ceramics to which the coloring component is added in the oxide state like the above guide member, most of the coloring component remains in the oxide state in the sintered body. Therefore, it had no translucency and had a blackish color, which was poor in decorativeness.

That is, in the case where the coloring component is added in the form of an oxide, since the oxide of the coloring component is present in the grain boundary of the alumina crystal in the sintered body, the light passing through the alumina crystal is Was absorbed or refracted by the above-mentioned oxide, and as a result, no translucency was obtained, and it had a blackish color.

Further, cobalt added as a color pigment,
Oxides of nickel, chromium, manganese, etc. cannot be fully densified because they do not have the effect of suppressing the growth of alumina particles.
kg / mm ² approximately, with a Vickers hardness 1600-180
The mechanical strength could not be increased so much as about 0 kg / mm ² . Therefore, using a fishing line guide formed of this colored alumina ceramics, the fishing line at high speed,
In addition, when used under a high load, there is a problem that the sliding surface is worn out and becomes unusable in a relatively short period of time.

[0009]

OBJECT OF THE INVENTION The present invention is capable of improving mechanical properties such as hardness and transverse rupture strength despite the addition of coloring components, and at the same time, has a light-transmitting feeling and is extremely decorative in abrasion resistance. To provide a decorative alumina decorative member and a manufacturing method thereof.

[0010]

SUMMARY OF THE INVENTION In view of the above problems, the present invention is directed to a wear-resistant alumina decorative member containing alumina as a main component and magnesium oxide and / or silicon oxide in an amount of 0.2% by weight or less. As a metal, which contains at least one metal selected from the group consisting of cobalt, nickel, chromium, manganese, and vanadium in the range of 0.005 to 0.1% by weight, and has a first peak strength (I ₀ ) and the intensity ratio (I / I ₀ ) of the first peak intensity (I) of the oxide crystal of the coloring component is I / I _0.
It is characterized in that it is formed of alumina ceramics having a value of <0.02.

The present invention also provides a method for producing the above-mentioned wear-resistant alumina decorative member, wherein the content of the magnesium oxide and / or silicon oxide powder is 0.2% by weight or less based on the alumina powder as the main component, and the coloring pigment. As a powder containing a metal salt of at least one of cobalt, nickel, chromium, manganese, and vanadium in the range of 0.03 to 0.5% by weight, and kneading and drying with a solvent and a binder to form a granule. It is characterized in that it is manufactured by filling the granulated body in a mold and molding it into a predetermined shape, followed by firing at a firing temperature of 1200 to 1800 ° C. in an air atmosphere or a vacuum atmosphere. Is.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION That is, the wear-resistant alumina decorative member according to the present invention is substantially composed of at least one metal selected from cobalt, nickel, chromium, manganese, and vanadium, which are coloring components in the sintered body. It does not exist in the state of oxide, but is almost completely dissolved in the alumina crystal. That is, by solid-solving the coloring component in the alumina crystal, there is no substance that absorbs or refracts light in the grain boundary of the alumina crystal, so that a high linear transmittance can be obtained, and a translucent alumina ceramic is obtained. be able to.

Therefore, in the wear-resistant alumina decorative member according to the present invention, those containing cobalt as a coloring component have a light-transmitting blue color, and those containing nickel have a light-transmitting green color. It may be colored translucent red when it contains chromium, pink when it contains manganese, or yellow when it contains vanadium. Yes,
For example, a material containing cobalt and chromium can be colored in a light-transmitting purple color. By combining the above-mentioned coloring components, various colors having decorativeness can be obtained.

Moreover, since the growth of the alumina particles can be suppressed by solid-solving the coloring component in the alumina crystal, it is possible to further densify and improve the mechanical properties.

However, in the present invention, the fact that the metal consisting of at least one of cobalt, nickel, chromium, manganese and vanadium does not substantially exist as an oxide means that the alumina crystal in the sintered body is measured by X-ray diffraction. the first peak intensity I _0, cobalt, nickel, chromium, manganese, intensity ratio when the first peak intensity of the oxide of a metal comprising one or more of vanadium is I of (I / I ₀₎
Means that I / I ₀ <0.02.

By the way, it is important that the content of the coloring component in the alumina ceramics is in the range of 0.005 to 0.1% by weight.

This is because if the content of the coloring component is less than 0.005% by weight, the color cannot be sufficiently colored, and the color tone is thin and the decorativeness is poor, and conversely, the content of the coloring component is small. This is because if it exceeds 0.1% by weight, the mechanical strength of the alumina decorative member decreases.

Further, magnesium oxide and / or silicon oxide may be contained as a sintering aid. For example, magnesium oxide has the effect of suppressing the growth of alumina particles, and silicon oxide has the effect of increasing the bonding force between alumina particles. Therefore, the mechanical strength of the alumina decorative member can be improved by adding these sintering aids. However, it is necessary to set the upper limit of the content of the sintering aid to 0.2% by weight. This is because when the content of the sintering aid is more than 0.2% by weight, the ratio of the sintering aid occupying the grain boundaries of the alumina crystal becomes too large, so that the translucent feeling is diminished and further sintering is performed. This is because the mechanical strength of the alumina decorative member decreases when the amount of the auxiliary agent increases. However, it is not always necessary to add a sintering aid to the wear-resistant alumina decorative member according to the present invention.

On the other hand, the content of alumina as a main component is preferably 99.7% by weight or more. This is because when the alumina content is less than 99.7% by weight, the mechanical strength of the alumina decorative member is significantly reduced. Even if the average crystal grain size of the alumina crystal is larger than 3.5 μm, the mechanical strength of the alumina decorative member is greatly reduced. Therefore, the average crystal grain size of the alumina crystal is 3.5 μm or less, preferably 3.0 μm. The following is good.

Further, the alumina decorative member according to the present invention needs to have a certain degree of light transmissivity, and preferably has a high linear transmittance in the entire visible light range, but at least 0. It suffices that the plate-shaped alumina decorative member processed to have a thickness of 5 mm has a linear transmittance of 15 T% or more when irradiated with light having a wavelength of 800 nm.

Next, a method of manufacturing the wear resistant alumina decorative member according to the present invention will be described.

First, an alumina powder having a purity of 99% or more and an average particle diameter of 1 μm or less is used as a main component. This is because if the amount of impurities in the alumina powder increases, it becomes impossible to obtain a feeling of light transmission, and the average particle diameter is 1 μm.
This is because if it is larger, the sinterability is reduced and the mechanical strength (flexural strength and hardness) of the alumina decorative member is reduced.

Then, with respect to this alumina powder, magnesium oxide and / or silicon oxide is contained in an amount of 0.2% by weight or less, and cobalt is used as a coloring pigment.
Powder of a metal salt composed of at least one of nickel, chromium, manganese, and vanadium is added in the range of 0.03 to 0.5% by weight. Here, the reason why the coloring component is added as a metal salt is to ionize the coloring components cobalt, nickel, chromium, and vanadium so that they are easily dissolved in alumina. Further, the addition amount of the above metal salt is set to 0.
The reason why the content is set to 03 to 0.5% by weight is that the content of the coloring component in the sintered body cannot be set to 0.005 to 0.1% by weight if the addition amount is larger or smaller than the above range. is there. The metal salt is a sulfide,
Nitrate or chloride may be used.

Then, a solvent and a binder are added to these raw materials, and the mixture is kneaded and dried to produce a granulated body, which is filled in a mold and molded into a predetermined shape, and then in an air atmosphere or a hydrogen atmosphere. The firing may be performed at a firing temperature of 1200 to 1800 ° C. Note that HIP treatment may be performed after firing, and the mechanical strength can be further improved by performing the HIP treatment.

The alumina decorative member according to the present invention formed by the above-mentioned manufacturing method has not only decorative properties but also an excellent machine having a Vickers hardness of 2000 kg / mm ² or more and a bending strength of 55 kg / mm ² or more. It can have a desired strength.

[0026]

Embodiments of the present invention will be described below.

FIG. 1 shows a fishing line guide 1 as an example of the wear-resistant alumina decorative member according to the present invention, which is a ring-shaped body 2 made of alumina ceramics exhibiting a light-transmitting blue color. The inner surface of is the sliding surface 3.

This fishing line guide 1 is obtained by adding 0.1% by weight of cobalt sulfate powder as a color pigment and 0.1% by weight of silicon oxide as a sintering aid to alumina powder having a purity of 99% or more. After mixing and pulverizing for 15 hours, add a binder to produce a granulation body by a spray dryer, fill the granulation body in a mold, and press-mold at a pressure of about 1.0 ton / cm ^2. A ring-shaped molded body is formed. After that, the obtained molded body was fired in the air at a firing temperature of about 1300 ° C. for 1 hour, and further subjected to HIP treatment to form it.

When the amount of cobalt in this fishing line guide 1 was measured by ICP emission spectroscopy, it was 0.018% by weight, and the presence or absence of cobalt oxide (Co ₃ O ₄ ) was measured by X-ray diffraction. ₃ O ₄ )
Did not include at all.

Separately, a sample made of alumina ceramics constituting the fishing line guide 1 was easily subjected to polishing to form a thin plate having a thickness of about 0.5 mm, and when irradiated with light having a wavelength of 800 nm, linear transmission of about 20 T% was performed. Moreover, the mechanical properties were measured, and it was found that the Vickers hardness was 2100 kg / mm ² , and the bending strength was 75 kg / mm ^2, which was sufficient mechanical strength.

(Experimental Example 1) Here, an abrasion-resistant alumina decorative member according to the present invention containing cobalt as a coloring component and a conventional abrasion-resistant alumina decorative member were prepared, and their characteristics were measured. .

The wear-resistant alumina decorative member according to the present invention contains 0.1% by weight of cobalt sulfate as a coloring pigment.
Alumina ceramics containing 0.1% by weight of silicon oxide as a sintering aid was prepared. As a conventional wear-resistant alumina decorative member, cobalt oxide of 0.1% by weight was used as a coloring pigment.
1% by weight and 0.1% magnesium oxide as a sintering aid.
Alumina ceramics added in the range of wt% were prepared.

Then, when these alumina decorative members were measured by X-ray diffraction, as shown in FIG. 2B, in the conventional wear-resistant alumina decorative member, cobalt oxide (Co ₃ O ₄ ) was used in addition to alumina crystals. The presence of crystals was confirmed. Further, the peak ratio (I / I ₀ ) of the first peak (I ₀ ) of the alumina crystal and the first peak (I) of the cobalt oxide (Co ₃ O ₄ ) crystal was determined to be I / I ₀ = 0.11. Met.

From this, it is understood that cobalt, which is a coloring component, exists in an oxide state in the alumina ceramics that constitutes the conventional wear-resistant alumina decorative member.

On the other hand, in the wear-resistant alumina decorative member according to the present invention, as shown in FIG. 2 (a), the peak of cobalt oxide (Co ₃ O ₄ ) crystal was not observed and only the presence of alumina crystal could be confirmed. It was

From this, it is understood that in the wear-resistant alumina decorative member according to the present invention, the coloring component cobalt is almost completely dissolved in the alumina crystal in the sintered body. Cobalt, which is a coloring component, reacts with alumina in the sintered body to cause spinel (CoAl
It is considered that the compound exists in the state of ₂ O ₄ ).

Next, these alumina decorative members were polished to a thickness of 0.5 mm, irradiated with light having a wavelength of 190 to 800 nm (visible light), and the linear transmittance was measured by an infrared spectrometer.

The respective results are shown in FIGS. 3 (a) and 3 (b), respectively.

As a result, in the conventional wear-resistant alumina decorative member of FIG. 3 (b), light transmission was not obtained in the entire wavelength range of 190 to 800 nm, and the linear transmittance was almost zero.

On the other hand, the wear-resistant alumina decorative member according to the present invention of FIG. 2 (a) transmits light in the wavelength light of 300 nm to 800 nm, and in particular, in the wavelength light of 800 nm, linear transmission of 20 T% is possible. Had a rate.

As can be seen from the above, the conventional wear-resistant alumina decorative member has a blackish blue color and lacks decorativeness, but the wear-resistant alumina decorative member according to the present invention is transparent. It had a pleasing blue color and had sufficient decorative properties.

(Experimental Example 2) The fishing line guide 1 of the present invention shown in FIG. 1 and, as a comparative example, alumina ceramics, silicon carbide ceramics, to which cobalt oxide was added as a coloring pigment,
A fishing line guide 1 made of zirconia ceramics and a TiN-based cermet material was trial-produced, and hardness and bending strength were measured for mechanical properties, and
Experiments were conducted on the sliding characteristics with the fishing line.

Regarding the measurement of hardness and bending strength, the surface of the sample was mirror-polished, and the hardness was measured according to the JISZ2244 test method, and the bending strength was measured according to the three-point bending test method of JIS R1601.

As to the sliding characteristics with respect to the fishing line, as shown in FIG. 4, a nylon fishing line 5 was applied to the sliding surface 3 of each fishing line guide 1 under a load of 1 kg, and a stroke of 300 mm was obtained. The state of wear of the sliding surface 3 was measured when the sliding surface 3 was reciprocated 10,000 times at a speed of reciprocating once every 2 seconds.

Then, when the sliding surface 3 was magnified 20 times, no abrasion marks were observed, and when abrasion marks were observed, x was measured.

In this experiment, Vickers hardness of 2000
kg / mm ² or more, the bending strength 55 kg / mm have ^two or more, and in sliding between the fishing line 5 what wear marks were observed on the slide surface 3 and be suitable as a fishing line guide 1.

The mechanical characteristics and sliding characteristics of each fishing line guide 1 are as shown in Table 1.

[0048]

[Table 1]

As a result, the sample No. No. 1 fishing line guide made of silicon carbide ceramics has a Vickers hardness of 2000k.
It had a high hardness of g / mm ² but a bending hardness of 5
Since it was about 0 kg / mm ² , wear marks with a depth of 1 μm or more were found on the sliding surface 3 due to sliding with the fishing line. Further, the silicon carbide based ceramics have a black color and are unsuitable for decorative members.

The sample No. No. 2 zirconia ceramic fishing line guide, and sample No. The TiN cermet fishing line guide of No. 3 has a bending hardness of 100 kg /
Although it has a strength as high as mm ² , since the Vickers strength is about 1200 to 1250 kg / mm ² , a sliding mark with a depth of 3 μm or more was found on the sliding surface 3 due to sliding with the fishing line 5.

Further, the sample No. The fishing line guides made of alumina ceramics Nos. 4 and 5 are those in which cobalt oxide and vanadium oxide are added as color pigments, respectively, so that the coloring component exists in an oxide state in the sintered body. Therefore, the bending strength is 40 kg / mm ² ,
Even with Vickers hardness, the mechanical strength could not be improved to about 1600 kg / mm ² . Therefore, fishing line 5
As a result of sliding with, wear marks having a depth of 1 μm or more were formed on the sliding surface 3. Also, the color tone was blackish blue and yellow, which was unsuitable for a decorative member.

Sample No. Since the alumina ceramic fishing line guide 6 of the present invention was added with a cobalt salt (cobalt sulfate) as a color pigment, it was possible to have a light-transmitting blue color tone in the sintered body. Since the cobalt content in the alloy was more than 0.1% by weight, the bending strength was 45 kg / mm ² and the Vickers hardness was 1800 kg / mm ^2, and the mechanical strength could not be improved. Therefore, by sliding with the fishing line 5, the sliding surface 3
In addition, wear marks with a depth of 1 μm or more were formed.

On the other hand, the sample No. 7 to sample No.
Since the alumina ceramic fishing line guide according to the present invention of No. 9 has a cobalt salt (cobalt sulfate) added as a coloring pigment, it can have a translucent blue color tone and can be used as a decorative member. Was suitable as. The content of cobalt in the sintered body is 0.0
05 to 0.1% by weight, and the content of magnesium oxide and / or silicon oxide as a sintering aid is 0.2% by weight.
55 kg / mm ^{2 in} Vickers hardness because it is below
As described above, the bending strength could be 2000 kg / mm ² or more. Therefore, no wear mark was found on the sliding surface 3 even after sliding the fishing line 5 10,000 times.

As a result, the sample No. 7 to sample No. 9
The alumina ceramics according to the present invention was suitable as a material for fishing line guides.

In this example, cobalt was used as the coloring component, but the same results were obtained when other coloring components such as nickel, chromium, manganese and vanadium were used.

[0056]

As described above, according to the present invention, the wear-resistant alumina decorative member contains alumina as a main component, magnesium oxide and / or silicon oxide in an amount of 0.2% by weight or less, and cobalt, nickel, chromium as coloring components. 0.005 to more than one metal of manganese and vanadium
0.1% by weight, respectively, and the intensity ratio (I) of the first peak intensity (I ₀ ) of the alumina crystal in the sintered body and the first peak intensity (I) of the oxide crystal of the above coloring component. Since / I ₀ ) is formed of alumina ceramics with I / I ₀ <0.02, it is possible to obtain sufficient color tone and light-transparent decorativeness. Moreover, mechanical properties such as hardness and transverse strength can be improved. Therefore, it can be suitably used for a long period of time as a member having a decorative property such as a guide member such as a fishing line guide or a fiber guide, or a watch case or other parts for a watch, and requiring abrasion resistance.

Further, in the present invention, the wear-resistant alumina decorative member is 0.2% by weight or less of magnesium oxide and / or silicon oxide powder with respect to alumina powder, and cobalt, nickel, chromium, manganese is used as a coloring pigment. A powder of a metal salt of at least one of 0.03 to 0.5% by weight, and kneading and drying with a solvent and a binder to produce a granulated body, and the granulated body is molded into a mold. It is manufactured by firing at a firing temperature of 1200 to 1800 ° C. in an air atmosphere or a vacuum atmosphere after molding into a predetermined shape and adding a trace amount of a coloring component to give a sufficient color tone. It is possible to give a feeling of translucency. Moreover, since the growth of alumina particles can be suppressed and the alumina particles can be densified, the mechanical strength can be greatly improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a fishing line guide which is an example of a wear-resistant alumina decorative member according to the present invention.

FIG. 2 (a) is a graph showing the peak intensity by X-ray diffraction of the wear-resistant alumina decorative member according to the present invention,
(B) is a graph showing the peak intensity by X-ray diffraction of a conventional wear-resistant alumina decorative member.

FIG. 3 (a) is a graph showing the linear transmittance of a wear-resistant alumina decorative member according to the present invention, and FIG. 3 (b) is a graph showing the linear transmittance of a conventional wear-resistant alumina decorative member.

FIG. 4 is a schematic view showing a sliding device for examining sliding characteristics.

[Explanation of symbols]

 1 ... Fishing line guide 2 ... Ring-shaped body 3 ... Sliding surface

Claims (2)

[Claims] 1. Alumina as a main component, magnesium oxide and / or silicon oxide at 0.2% by weight or less, and a coloring component containing at least one metal selected from cobalt, nickel, chromium, manganese, and vanadium as a coloring component. 005-0.
1% by weight, respectively, and the intensity ratio (I) of the first peak intensity (I ₀ ) of the alumina crystal in the sintered body and the first peak intensity (I) of the oxide crystal of the coloring component is
/ I ₀ ) formed of alumina ceramics having I / I ₀ <0.02. 2. Magnesium oxide and / or silicon oxide powder in an amount of 0.2% by weight or less based on alumina powder as a main component, and at least one of cobalt, nickel, chromium, manganese, and vanadium as a coloring pigment. A powder of a metal salt is added in the range of 0.03 to 0.5% by weight, and the mixture is kneaded and dried with a solvent and a binder to prepare a granulated body, and the granulated body is filled in a mold to a predetermined size. A method for producing a wear-resistant alumina decorative member, which comprises firing into an air atmosphere or a vacuum atmosphere at a firing temperature of 1200 to 1800 ° C. after shaping into a shape.