JPH0734163A - Gold-colored sintered body and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Structure] At least titanium, nitrogen, and boron are main constituent elements, and 64.0 to 71.0% by weight of titanium and 1.
4 to 9.0% by weight, boron 21.4 to 30.0% by weight
Is a golden-colored sintered body containing 3% by weight or less of carbon, and titanium nitride and titanium boride are present as crystalline phases in the sintered body. Such a gold-colored sintered body contains 60 to 90% by weight of titanium boride.
Then, it is obtained by sintering a molded body containing 0.5 to 3.0% by weight of boron metal and the balance containing titanium nitride. [Effect] Sufficiently high strength, Young's modulus and excellent oxidation resistance, corrosion resistance, without reducing the original high hardness of titanium nitride.
A gold-colored sintered body having wear resistance can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is, for example, a sliding member such as fishing tackle, a watch member, a brooch, a necklace, a medal, a golden decorative member with a beautiful color tone such as a button, a wall material, and wear resistance of various kitchen members The present invention relates to a gold-colored sintered body having excellent properties used for a member and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, for example, as a gold-colored material used for decoration, pure gold, alloys thereof, various metals such as brass, or a metal surface plated with gold has been used. All of them have low hardness, and have a drawback that the surface is likely to be scratched or cracked due to contact with a hard substance.

In order to solve such a drawback, conventionally, titanium nitride has been used which has a high hardness, an excellent oxidation resistance and a beautiful golden color. However,
To obtain titanium nitride as a plain sintered body, 2300
It was necessary to sinter at a high temperature of ℃ or more and by a special method. Further, the obtained sintered body had a drawback that it had a low bending strength and was brittle.

Therefore, recently, titanium nitride is replaced with N.
Gold-colored sintered alloys bonded with iron group metals such as i and Co have come to be used (see Japanese Patent Publication No. 2-58335).

[0005]

However, when a sintering aid composed of an iron group metal is added to titanium nitride, the corrosion of the metal phase region in the sintered body progresses, which causes, for example, seawater or sweat. There are problems that the color changes, the coloration of the decorative member is impaired, and abrasion occurs due to a chemical reaction or the like.

In addition, the sintering aid has poor wettability with titanium nitride, and has many defects that many voids appear throughout the crystal and grain boundaries, and a vivid mirror surface does not appear even after mirror polishing. .

Further, all the sintered alloys obtained by adding an iron group metal and other corrosion resistance aids to titanium nitride and having a Vickers hardness H _V of 1500 kg / mm ² or less, With the widespread use of various ceramic products and high hardness coating products in recent years, it is not always possible to say that they have sufficient hardness in terms of wear resistance and scratch resistance.

Further, since a sufficiently high Young's modulus cannot be obtained with the above-mentioned sintered alloy using the iron group metal or the like,
For example, processing becomes extremely difficult in terms of providing high dimensional accuracy required for inlaid products and the like.

[0009]

As a result of repeated studies on the above-mentioned problems, the present inventor found that when titanium boride and boron metal were added to titanium nitride and sintered, the original high hardness of titanium nitride was obtained. The inventors have found that a gold-colored sintered body having sufficiently high strength, Young's modulus, and excellent corrosion resistance and wear resistance can be obtained without reducing the value of the present invention, and the present invention has been accomplished.

That is, the gold-colored sintered body of the present invention contains at least titanium, nitrogen, and boron as main constituent elements, and titanium at 6
A gold-colored sintered body containing 4.0 to 71.0% by weight, nitrogen in the range of 1.4 to 9.0% by weight, and boron in the ratio of 21.4 to 30.0% by weight, and having a carbon content of It is 3% by weight or less, and titanium nitride and titanium boride are present as crystal phases in the sintered body. Such a golden sintered body,
60 to 90% by weight of titanium boride and 0.5 of boron metal.
It is obtained by sintering a molded body containing .about.3.0% by weight and the balance containing titanium nitride.

Here, the overall composition of the sintered body is titanium 64.
0 to 71.0% by weight, nitrogen 1.4 to 9.0% by weight, and boron 21.4 to 30.0% by weight consist of titanium having less than 64% by weight, resulting in poor gloss and corrosion resistance. Is poor, and if it exceeds 71% by weight, the strength and hardness decrease and the wear resistance deteriorates. Also, nitrogen is 1.
If it is less than 4% by weight, the golden color tone becomes dull and silver,
This is because if the amount is more than 9.0% by weight, the wear resistance is deteriorated. Further, if the amount of boron is less than 21.4% by weight, the abrasion resistance is poor, and if it is more than 30.0% by weight, the color tone and corrosion resistance are poor, and the strength is remarkably lowered.

The sintered body must have a carbon content of 3% by weight or less.

This is because when the carbon content is more than 3% by weight, the color tone of the sintered body becomes dark (reddish) and the corrosion resistance is deteriorated. In particular, it is desirable that the carbon content be 1.5% by weight or less.

The sintered body of the present invention is preferably formed by substituting a part of titanium with 4% by weight or less of at least one metal element of Groups 4a, 5a and 6a of the Periodic Table. This is because a small amount of substitution improves the sinterability.
The reason why the amount of substitution is 4% by weight or less is that the amount of substitution is 4
This is because if the content is more than the weight%, the sinterability deteriorates, and further the corrosion resistance, the oxidation resistance and the reaction resistance deteriorate. As a result, the wear resistance also deteriorates.

The amount of substitution is preferably 0.5 to 3.0% by weight. Further, as the metal elements of the 4a, 5a, 6a group of the periodic table to be replaced, Ti, W, M, Ta, Nb, V, Cr,
There is Zr. The substituting element may be added as a carbide, nitride or carbonitride thereof, or may be added by using a crushed ball containing the substituting element.

In the structure of the gold-colored sintered body of the present invention, boron metal and metal elements of Groups 4a, 5a and 6a of the periodic table are solid-dissolved in the dispersed particle phase of titanium nitride and titanium boride. It is considered that the boron metal and the metal elements of Groups 4a, 5a and 6a of the periodic table improve the wettability of titanium nitride and titanium boride and suppress the decomposition of titanium boride.

The amount of titanium and nitrogen contained in the sintered body is preferably 67 to 70% by weight of titanium and 2.0 to 7.0% by weight of nitrogen. The average crystal grain size of the titanium nitride crystal grains is preferably 3 μm or less. Such an average crystal grain size is obtained by pulverizing the raw material powder to 3 μm or less and adding 60 to 90% by weight of titanium boride and 0.5 to 3.0% by weight of boron metal to titanium nitride. It can be controlled by firing at an appropriate temperature.

Titanium nitride containing 60 to 90% by weight of titanium boride was fired because titanium boride was 60% by weight.
If it is less than 10%, wear resistance cannot be improved, and
When the content is more than 0% by weight, titanium and boron are decomposed during sintering and defects such as voids are remarkably generated in the crystal, and the strength is remarkably lowered. In addition, this sintered body has a dull white silvery mirror-like state and is unsuitable as a decorative member and a wear-resistant member. Titanium boride contained in titanium nitride is preferably mixed in a proportion of 68 to 85% by weight.

In addition, 0.5 to 3.0% by weight of boron metal added to titanium nitride was added and fired.
If the amount is less than 3% by weight, the strength will be reduced, and if the amount is more than 3% by weight, the corrosion resistance and the oxidation resistance will be poor.

The golden sintered alloy of the present invention is titanium nitride,
60 to 90% by weight of titanium boride and 0.5 of boron metal.
It can be obtained by sintering a mixed powder added with up to 3% by weight. The average particle diameter of the titanium nitride raw material powder and the titanium boride raw material powder should be 4 μm or less, and activation of sinterability should be performed. From the above point, 3 μm or less is particularly preferable.

The boron metal may be either amorphous boron or crystallized boron, but amorphous boron is particularly preferable from the viewpoint of activating sinterability and reactivity.

The particle size of the boron metal may be 4 μm or less, especially 2 μm from the viewpoint of dispersion and activation.
The following are preferred.

In the method for producing a gold-colored sintered alloy of the present invention, a part of titanium nitride is 5 wt% of at least one of carbides, nitrides and carbonitrides of metal elements of Groups 4a, 5a and 6a of the Periodic Table. It is desirable to replace the following. This is because a small amount of substitution improves the sinterability. And
The reason why the amount of substitution is 5% by weight or less is that if the amount of substitution is more than 5% by weight, the sinterability deteriorates. The amount of substitution is preferably 0.5 to 4.0% by weight. The substitution element may be added by using a crushed ball containing the substitution element.

The method for producing the golden-colored sintered body of the present invention will be described in detail. To the titanium nitride raw material powder, titanium boride raw material powder, boron metal raw material powder, and other powders are added in the above-mentioned proportions, if desired. After uniform mixing, the mixed powder is pressure-molded by a known molding method, for example, press molding, and fired. The firing is performed in a non-oxidizing atmosphere such as nitrogen or argon or in a vacuum atmosphere (vacuum degree of 10 ^-2 to 10 ^-5 to
rr) in the temperature range of 1700 to 2000 ° C.
Do for 5 to 3 hours. In the process of this sintering, boron and nitrogen decompose and scatter as gas. Therefore, it is necessary to control the raw material composition, the firing time, etc. so that the composition of the sintered body becomes the above-mentioned composition. As a result, it is possible to obtain a high-hardness golden-colored sintered body that has high strength, oxidation resistance, corrosion resistance, reaction resistance, and wear resistance.

[0025]

According to the present invention, wear resistance having industrially usable high strength, Young's modulus (rigidity) and excellent oxidation resistance, corrosion resistance, and reaction resistance without deteriorating the original high hardness of titanium nitride. It is possible to obtain a golden-colored sintered body having excellent properties.

This is because by adding boron metal to titanium nitride, the boron uniformly wraps the surface of the titanium nitride particles to form high hardness particles and improves the wettability with titanium boride. . Further, titanium boride sufficiently wet with titanium nitride improves oxidation resistance and corrosion resistance, whereby a gold-colored sintered body having excellent wear resistance can be obtained.

[0027]

The present invention will be described below with reference to the following examples.

Titanium nitride (TiN) powder, titanium boride (TiB ₂ ) powder, amorphous boron metal (a-
B) Powder and other powders were mixed in the ratio shown in Table 1 to 68
Mixed and crushed for hours. After drying this, 4% by weight of paraffin was added and pressure-molded at a pressure of 1.5 ton / cm ² ,
After debindering, in a vacuum of 10 ⁻³ torr, 18
It was baked at 50 ° C. for 1 hour.

[0029]

[Table 1]

After grinding the surface of the obtained sintered body, the bending strength and Young's modulus (rigidity) were measured. Further, after mirror polishing, its color tone, Vickers hardness, and mirror surface corrosion resistance and abrasion resistance were measured. Further, the sintered body was crushed and the composition of the sintered body was measured.

The bending strength is in accordance with JIS R1601 three-point bending test method, and the Vickers hardness is measured in JIS Z2244.
The test method was followed. The Young's modulus was calculated by measuring the dynamic elastic modulus by the ultrasonic pulse method. As for the corrosion resistance test, artificial sweat (PH4.7) conforming to the ISO (International Organization for Standardization) standard is used as a corrosive solution, and the sample is dipped in this corrosive solution, and salt water (4 wt% / vol)
Salt spray test (JISZ)
2371). Further, regarding wear resistance (tribochemical reactivity resistance), in a vertical friction wear test (ball-on-disk type), a sample rotating disk (diameter 4
0 mm), fixed ball (diameter 9.5 mm), friction radius (16 mm), applied load (0.5 Kgf), peripheral speed (36
m / min), test time (60 min), and atmosphere (salt spray in the air). The composition of the sintered body is IC
Quantitative analysis of titanium, boron, nitrogen, carbon and other metal elements of groups 4a, 5a and 6a of the periodic table was carried out by P emission spectroscopy and a detector of thermal conductivity of carbon and nitrogen gas manufactured by LECO. Further, when the crystal phase was identified by an X-ray diffractometer, it was confirmed that titanium nitride and titanium boride were present in the golden sintered alloy of the present invention. The results are shown in Table 2.

[0032]

[Table 2]

In Table 2, regarding the results of the corrosion resistance test, both the sweat resistance test and the salt spray test show no discoloration and corrosion and no deterioration in color tone. On the contrary, discoloration or corrosion was observed. The color tone was gradually deteriorated and was unsuitable as a decorative member. Further, the results of the abrasion resistance test were judged by the depth of the abrasion mark of the sample. When there was no abrasion, the mark was ◯, and when abrasion occurred, the mark was x.

As is clear from Table 2, the gold-colored sintered body within the scope of the present invention has excellent wear resistance (tribochemical reaction resistance) and corrosion resistance, and has excellent hardness and no problem in decorative use. Shows strength. In addition, the Young's modulus of the sintered body is extremely high, which enables accurate processing. For comparison, the Young's moduli of the other sintered bodies are 4.40 for SiC, 3.50 for Al ₂ O ₃ , and 4.25 for TiN. Further, it was found that when the sintered body of the present invention was polished, a smooth and bright gold-colored mirror surface appeared, resulting in a remarkably excellent golden decorative member and wear-resistant member.

On the other hand, the samples out of the composition range of the present invention were inferior in strength, corrosion resistance and abrasion resistance, and were all unsuitable as a golden decorative member.

[0036]

As described above, according to the gold-colored sintered body and the method for producing the same of the present invention, sufficiently high strength, Young's modulus (rigidity) and excellent acid resistance can be achieved without lowering the high hardness inherent to titanium nitride. It is possible to obtain a gold-colored sintered body that has chemical resistance, corrosion resistance, and wear resistance.
While it has hardness and strength without any hindrance, it enables highly accurate processing, has improved corrosion resistance compared to conventional gold-colored sintered bodies, and a vivid and smooth golden mirror surface appears. As a sliding member having a beautiful color tone that does not cause corrosion or scratches for a long period of time, a member for gold decoration and a wear resistant member, it can be suitably used for wall materials, clock members, brooches, necklaces, medals, buttons, fishing tackles and the like.

Claims (2)

[Claims] 1. At least titanium, nitrogen and boron as main constituent elements, 64.0 to 71.0% by weight of titanium, 1.4 to 9.0% by weight of nitrogen, and 21.4 to 30.0% of boron. A gold-colored sintered body containing at a weight% ratio, wherein the carbon content is 3% by weight or less, and titanium nitride and titanium boride are present as crystal phases in the sintered body. Sintered body. 2. A gold color characterized by comprising sintering a molded body containing 60 to 90% by weight of titanium boride, 0.5 to 3.0% by weight of boron metal, and the balance containing titanium nitride. Manufacturing method of sintered body.