JPH059644A - Golden sintered alloy - Google Patents

Abstract

PURPOSE:To produce a golden sintered allay having a clear fine golden color tone by blending specified percentages of Ti, Fe family metals, group VIa elements of the periodic table, C and N. CONSTITUTION:A golden sintered alloy consisting of 55-75wt.% Ti, 3-29wt.% Fe family metals (Ni, Fe and Co) and VIa group elements (Cr, Mo and W) of the periodic table and the balance C and N as nonmetallic elements is prepd. The amt. of C is <=10wt.% of the total amt. of the nonmetallic elements. In the sintered compact, Ti is chiefly in existence as TiN or TiCN and forms a hard phase. The pref. amt. of the Fe family metals is about 1-20wt.% and that of the group VIa elements of the periodic table is about 1-20wt.%. The golden sintered alloy has a clear fine color tone and does not cause corrosion and scratch over a long period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gold-colored sintered alloy having a gold color used for decoration, for example.

[0002]

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

Therefore, in recent years, in order to solve the above-mentioned disadvantages, a metal-nitride, for example, a gold-colored sintered alloy in which titanium nitride or the like is bonded with a metal such as Ni or Co has come to be used. (See Japanese Patent Publication No. 2-58335, etc.).

By the way, since the above-mentioned gold-colored sintered alloy generally has poor sinterability, in order to improve such sinterability, carbides and carbonitrides of elements of Groups 4a, 5a and 6a of the Periodic Table are formed. It was necessary to add various additives such as a product and calcinate.

[0005]

However, there has been a problem that the color tone is remarkably changed from the original golden color of the sintered body by the addition of these various additives. In particular, in the addition of carbides and carbonitrides of elements of Groups 4a and 5a of the Periodic Table, which are good for improving the sinterability, the color tone of the sintered body changed to red copper color, and a clear and good gold color was obtained. There was a problem that no color was obtained.

[0006]

[Means for Solving the Problems] The inventors of the present invention have conducted various studies in order to obtain a gold-colored sintered alloy having a clear and good gold color tone, and as a result, the ratio of carbon to nitrogen of the non-metal element has been determined. It has been found that the effect as described above can be obtained when the amount is not more than a certain value.

That is, in the gold-colored sintered alloy of the present invention, titanium is contained in an amount of 55 to 75% by weight based on the total amount, the iron group metal and the periodic table 6
The a-group element is 3 to 29% by weight in the total amount, and the balance is composed of carbon and nitrogen, which are nonmetallic elements, and the ratio of carbon to the nonmetallic element is 10% by weight or less. As the iron group metal, Ni, Fe, Co
And elements of Group 6a of the Periodic Table are Cr, Mo,
There is W.

The reason why Ti is 55 to 75% by weight in the total amount is that if it is less than 55% by weight, the color tone of the golden color becomes light, and if it exceeds 75% by weight, the sinterability is lowered and the strength is lowered. Because. This amount is preferably 60 to 75% by weight. Incidentally, Ti mainly exists as TiN or TiCN in the sintered body and forms a hard phase.

Further, the iron group metal and the Group 6a element of the periodic table are set to 3 to 29% by weight in the total amount, because if the amount is less than 3% by weight, sintering tends to be difficult. This is because the strength of the sintered body decreases. On the other hand, when it is more than 29% by weight, the hardness of the sintered body is remarkably lowered and the corrosion resistance is lowered. The amount of iron group metal and Group 6a element of the periodic table is 5 to 29% by weight.
Is desirable. The iron group metal forms a binder phase in the sintered body, and the Group 6a element of the periodic table forms a hard phase or a binder phase. Further, specifically, the iron group metal is 1
-20% by weight, Group 6a element of the periodic table is 1-20% by weight
It is desirable to exist in the ratio of.

Further, the ratio of carbon to the non-metal element is 1
The reason why the content is 0% by weight or less is that, when the content is more than 10% by weight, the original golden color becomes reddish and the reddish copper color changes to grayish brown as the carbon ratio increases. Therefore, in order to maintain a clear and good golden color tone, the ratio of carbon to the non-metal element needs to be 10% by weight or less. In particular, it is desirable that the proportion of carbon, which is a nonmetallic element, be 8% by weight or less. The balance contains a small amount of unavoidable impurities.

The gold-colored sintered alloy of the present invention is obtained by mixing, as a raw material powder, Ti nitride and carbonitride powder with an iron group metal and an element of Group 6a of the periodic table, in an organic solvent such as acetone. After mixing and pulverizing for a predetermined time, add a predetermined amount of binder, press-mold into a desired shape at a predetermined pressure, debinder this at a predetermined temperature in a non-oxidizing atmosphere, and then bake at a predetermined temperature. can get. For example, Ti nitride and carbonitride having a particle size of 0.5 to 3.0 μm, Ni and Co having a particle size of 0.1 to 1.0 μm as an iron group metal, and a group 6a element of the periodic table. Particle size 1.0
〜 10.0μm each powder such as WC and Cr ₃ C ₂ is weighed and mixed, and this is mixed and pulverized in an organic solvent such as acetone for about 68 hours, and then paraffin is added to obtain a desired shape at 1.5 ton / cm ^2. Press molding. It is obtained by debinding the molded product at a predetermined temperature in a non-oxidizing atmosphere, and then performing vacuum firing at a predetermined temperature for 1 hour in a vacuum heating furnace. At this time, W and Cr are added as carbides as raw material powders, and metal Cr and metal W are added in the process of firing.
However, it does not exist in Cr ₃ C ₂ and WC because it melts in the binding metal or solid-solves in TiN or TiCN. Also,
TiN and TiCN are preferably present as crystal particles having a particle size of 10 μm or less.

As a firing method, the degree of vacuum is 10 ^-1 to 10 ^-4.
Firing is performed at a temperature of 1300 to 1800 ° C. under reduced pressure or no pressure in a torr atmosphere or various atmospheres. The firing time is usually 0.5 to 5 hours, although it depends on the size of the sample. After firing, the surface of the sintered body is mirror-polished with a diamond paste or the like, whereby a glossy, clear and good gold color appears.

The gold-colored sintered alloy thus obtained is
For example, it can be used for decoration of watch cases, watch bands, necklaces, broaches, commemorative medals, buttons, scissors, blades, fishing tackle, and the like.

[0014]

EXAMPLES T having a particle size of 0.5 to 3.0 μm as a raw material powder
iN, TiCN with a particle size of 0.5 to 3.0 μm, particle size of 1.0
~ 10.0 μm Cr ₃ C ₂ , grain size 1.0 to 10.0 μ
m WC, grain size 0.1-1.0 μm Ni, grain size 0.1
.About.1.0 .mu.m Co powders were used, and these were weighed and mixed so that the respective metal amounts of the final sintered body were in the ratios shown in Table 1, and were mixed and pulverized in an organic solvent such as acetone for about 68 hours. After that, paraffin is added in an amount of 4 to 5% by weight, and pressure-molded into a desired shape at 1.5 ton / cm ² . After demolding the molded product at a predetermined temperature in a non-oxidizing atmosphere, the degree of vacuum is 1
Vacuum baking was performed for 1 hour at 1400 to 1500 ° C. in a vacuum heating furnace of 0 ⁻² torr. The final sintered body thus obtained is analyzed by ICP emission spectroscopy,
The results are shown in Table 1.

[0015]

[Table 1]

Then, the sintered body was surface-ground and mirror-polished, after which the color tone, bending strength, Vickers hardness (Hv), and corrosion resistance of the sample were tested. The bending strength is measured by JI
According to the SR1601 three-point bending test method, the Vickers hardness was measured according to the JISZ2244 test method, and the porosity was measured according to the Archimedes method. Then, for the corrosion resistance test, artificial sweat (pH 4.7) conforming to the ISO (International Organization for Standardization) standard was used as a corrosive liquid, and the sample was mirror-polished in the artificial sweat kept at a temperature of 40 ° C ± 2 ° C. Lower half 24
This was performed by immersing for a time and observing the condition of the polished surface of the sample after the immersion. The results are shown in Table 2.

[0017]

[Table 2]

In Tables 1 and 2, sample numbers marked with * indicate those outside the scope of the present invention. Further, regarding the results of the corrosion resistance test in Table 2, the mark ○ indicates no discoloration and corrosion, and the mark Δ indicates discoloration, ×
The mark indicates that not only discoloration but also corrosion was observed.

As is clear from Table 2, sample number 2
It was found that when the golden sintered alloys of ~ 6 were polished, a brilliant and clear golden-colored mirror surface appeared, resulting in a remarkably excellent golden sintered alloy. On the other hand, the sintered gold alloy of Sample No. 1 was defective in sintering. The hardness of the golden sintered alloys of sample numbers 9 and 11 is low. Sample Nos. 7-11 are golden with a strong redness,
It became a dark golden color and a red copper color, and neither was suitable as a golden sintered alloy.

[0020]

As described in detail above, according to the present invention, a clear and good golden mirror surface appears as compared with the conventional gold-colored sintered alloy, and as a result, corrosion and scratches do not occur for a long period of time. As a golden sintered alloy having a clear and good color tone, it can be used for decoration of watch cases, watch bands, necklaces, broaches, commemorative medals, buttons, scissors, fishing tackle, and the like.

Claims (1)

Claims: 1. The total amount of titanium is 55 to 75% by weight, the iron group metal and Group 6a element of the Periodic Table are 3 to 29% by weight, and the balance is carbon which is a nonmetallic element. It is composed of nitrogen and the ratio of carbon to the non-metallic element is 10
A gold-colored sintered alloy characterized by being less than or equal to wt%.