JPS5949297B2 - Hard sintered alloy for decorative parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is suitable for use in manufacturing decorative parts such as watch parts, and has a color tone equivalent to the lemon-like gold color of tantalum carbide (hereinafter referred to as TaC)-based hard sintered alloy. The present invention relates to a hard sintered alloy having the following characteristics.

In general, the main properties required for decorative parts are: 1. The surface should be beautiful; 2. It should not corrode due to sweat during use; and 3. The surface should not be damaged by contact with hard objects during use. You can list things like, “There is no such thing.”

Conventionally, stainless steel and materials whose surfaces are plated with gold or other materials have been used in many cases to manufacture decorative parts such as watch sides, but these materials do not have the properties 1 and 2 above. Although the results were satisfactory, property 3 above was not satisfied.

Recently, carbides and nitrides of transition metals in groups 4a and 5a of the periodic table, and carbides of transition metals in group 6a of the periodic table have been used as materials for manufacturing scratch-resistant decorative parts. Hard sintered alloys made mainly of one or more types and sintered using a binder such as Co or Ni have been proposed and put into practical use.

Among these, hard sintered alloys mainly made of TaC exhibit a deep pale lemon-gold color that cannot be seen in gold-plated materials, making them extremely valuable as materials for high-grade decorative parts. be.

However, TaC-based hard sintered alloys are extremely expensive because Ta is in a depleted state as a resource and it is difficult to obtain stable raw materials.

Therefore, by reducing the TaC content or not containing it at all, a hard sintered alloy having a color tone equivalent to the lemon-gold color of a TaC-based hard sintered alloy, which usually contains about 90% TaC by weight, can be produced. There is an urgent need to manufacture them at low cost using readily available raw materials.

Therefore, from the above-mentioned viewpoint, the present inventors developed a hard sintered alloy having a color tone equivalent to the deep pale lemon gold color of the conventional TaC-based hard sintered alloy, using readily available raw materials. In order to manufacture it at a low cost, it cannot be used as a substitute material for the conventional TaC-based hard sintered alloy, especially since the alloy color tone is orange-gold with a slightly reddish-dark color, and also has poor sintering properties. In order to obtain a dense sintered body, high temperatures are required, and even if a dense sintered body is obtained, it has disadvantages such as poor polishing properties and difficulty in achieving a mirror-like polished surface. The above-mentioned conventional TiN-based hard sintered alloy which is easy to obtain and has low manufacturing cost, that is, one or two of Co and Ni: 3 to 30% by weight;
Contains Mo: 1 to 15%, Cr: O,: 2 to 6%, and further contains vanadium carbide (VC): 0 as necessary.
．． Contains 1-15% of TiN and unavoidable impurities:
As a result of research focusing on a TiN-based hard sintered alloy having a component composition consisting of the following, (a) When oxygen is included in TiN, which is the main component,
The alloy color tone is when the reddishness disappears and it becomes a lemon-like gold color.

(b) TiN and Zr+ Hft V+ Nbt Ta
.

When a solid solution of one or more metals of M O+ Cr and W with a carbide is included as a main alloy component, sinterability and polishability are significantly improved.

The findings shown in a and b have been obtained above.

This invention was made based on the above knowledge, and in weight percent, one or two of Co and Ni: 3 to 30%,
Contains Mo: 1 to 15%, Cr: 0.2 to 6%, and further contains VC: 0.1 to 15% as necessary, composite metal carbonitride oxide and inevitable impurities: having a component composition consisting of a plate, and the composite metal carbonitride oxide,
Chemical formula: (Ti uj Mv) When expressed as CxNyOz, M: Zr, Hfy V+ Nbt Ta2
One or more of Mo, Crt and W, u + v = 1, 0.95≦x + y 1.0.4≦U≦0.995.0.005≦V≦0
．． 6.0.2≦X≦0,6, 0.4≦y≦0.8.
It is characterized by a hard sintered alloy that satisfies the following conditions: 0.01≦2≦0.1, has excellent sinterability and polishability, and has a lemon-like golden color tone.

Next, the reason why the composition range of the alloy of the present invention is limited as described above will be explained.

Value) Co and Ni Co and Ni are the main components constituting the bonded phase, but
If the content is less than 3%, the binder phase formation is insufficient and voids tend to remain in the sintered body, which is undesirable. On the other hand, if the content exceeds 30%, the material becomes soft and the desired high hardness is not achieved. Therefore, the content was set at 3 to 30%.

(b)M.

Mo has the effect of improving the wettability between the hard phase and the binder phase during the sintering process, as well as absorbing free carbon in the raw material powder, which is one of the reasons for giving the color a reddish tinge, to form carbide. However, if the content is less than 1%, the desired effect cannot be obtained, while if the content exceeds 15%, the alloy strength will decrease.
It was set at 15%.

(c) Cr Cr mainly acts as a solid solution in the binder phase to improve the corrosion resistance of the alloy, but if its content is less than 0.2%, the desired effect of improving corrosion resistance cannot be obtained; If the content exceeds 0.2 to 6, the alloy strength will decrease, so the content was set at 0.2 to 6.

(d) VC When manufacturing hard sintered alloys containing carbonitride oxides, VC improves sinterability, further increases alloy strength, and prevents peeling during polishing, making it more beautiful. Since it has the effect of imparting a mirror surface, it is included as necessary especially when these properties are required, but if its content is less than 0.1%, the desired effect of improving the above effect cannot be obtained; If the content exceeds 15%, the alloy strength will decrease, so the content was set at 0.1 to 15%.

(e) (Ti uy Mv)CxNyOz(1)
u+v=1.0.4≦U≦0.995.0.005≦
V≦0.6, Ti is the main component that causes the alloy to develop a golden color when coexisting with nitrogen, but in the relative proportion to the metal M contained for the purpose of improving the sinterability and polishability of the alloy. ,
If U is less than 0.4, the desired gold color cannot be secured, while if the relative proportion U exceeds 0.995, the proportion of metal M becomes relatively too small and the desired sinterability and polishing properties cannot be achieved. Since no sexual improvement effect was obtained, the value of U was set to 0.4.
~0.995.

As a result, the value of V representing the content of metal M is 0.005
~0.6, which naturally satisfies u + v21.

(2) 0.95≦x + y + z≦1x 10y +
z defines the lower limit of the deviation from the stoichiometric composition, and since the smaller this value is, the lower the sinterability is, the lower limit is set at 0.95.

(3) 0.2≦X≦0.6 X defines the content of carbon that has the effect of improving the sinterability and polishability of the alloy, but if X is less than 0.2, the desired improvement On the other hand, if X exceeds 0.6, the amount of nitrogen is relatively too small and the desired golden color cannot be obtained, so 0.2≦X≦0.
．． 6.

(4) 0.4≦y≦0.8 y specifies the amount of nitrogen, but if y is less than 0.4, the gold color will be too pale, while if y exceeds 0.8, the sinterability will be poor. starts to decrease, so 0,4≦y≦0.8
It was determined that

(5) 0.01≦2≦0.1 2 specifies the content of oxygen that has the effect of removing red meat from the alloy color tone and giving it a lemon-like golden color tone, but if it is less than 0.01, The desired color tone cannot be ensured, and if 2 exceeds 0.1, the sinterability will deteriorate, so it was set as 0.01≦2≦0.1.

The alloy of the present invention can be manufactured by a normal powder metallurgy method, but when sintered in a vacuum, the N component is mainly extracted as N2 gas, which tends to form cavities in the sintered body. Therefore, the sintering atmosphere is preferably a N2 atmosphere under reduced pressure.

Next, the alloy of the present invention will be specifically explained using examples.

Example 1 The raw material powder had an average particle size of 1.5 μm (T i
O,65Ta O,35)C0,31No,6oOu
, o5 powder and Ni powder, 1.3 μm Mo powder,
Prepare 1.7 μm Cr powder, and combine these raw powders with
Ni powder: 15 cm, Mo powder: 5%, Cr powder: 3%,
(TiO,65TaO,35)C0,31NO
, 6000, 05 powder: Blend in the composition of residue (wt%), mixed in a wet ball mill, dried, and then molded into a green compact. The hard sintered alloy 1 of the present invention having substantially the same composition as the blended composition was manufactured by sintering at a temperature of 1500° C. for 1 hour.

The hard sintered alloy 1 of the present invention obtained as a result is similar to the conventional TaC
It had a lemon-like golden mirror surface equivalent to that of the base hard sintered alloy, and also had a high hardness of Vickers hardness (HV): 1520.

In addition, regarding the above-mentioned hard sintered alloy 1 of the present invention, inlet sweat (pH 4,7) conforming to the 15O (International Organization for Standardization) standard was used as a corrosive liquid, and the inlet sweat was kept at a temperature of 40°C ± 2°C. A corrosion resistance test was conducted in which the lower half of the mirror-polished specimen was immersed for 24 hours and the appearance of spiders on the polished surface of the specimen was observed after immersion. No spiders appeared at all, indicating good corrosion resistance. Indicated.

Example 2 The raw material powder had an average particle size of 1.7 μm (Ti0
．． 72Nb0.28)C0,25NO,6900,0
5 powder and Cr powder, 1.5 μm Ni powder and VC powder, and 1.3 μm Mo powder were prepared.
Powder: 5%, Cr powder: 4T (Ti0.72Nb0
．． 2B) C0,25NO06900,05 powder: The hard material of the present invention which is blended with the blended composition of the remainder (weight) and has substantially the same component composition as the blended composition under the same manufacturing conditions as in Example 1. Sintered alloy 2 was manufactured.

When the hard sintered alloy 2 of the present invention obtained as a result was mirror-polished, a mirror surface with exactly the same deep pale lemon gold color as the conventional TaC-based hard sintered alloy was obtained, and the hardness was also improved. When measured, Vickers hardness (Hv)
:1490 was shown.

Example 3 The raw material powder had an average particle size of 1.8 μm (TiO
,59Zr0.11Ta0.30)C0,31NO,
6200,06 powder, 2.0 μm (Ti□, 64H
f O,05Nb O,31)C0,34NO,5so
o, os powder and (T i O,70V O,30)
CO, 45NO, 5100, 03 powder, all 1.
(T i O, 60 Ta O, 25 NO
0,15) C0,41NO,4800,09 powder (T
i O,52Nb O,31Cr O,05W0.12
) CO, 52NO, 4100, 07 powder, Ni powder,
and VC powder, Mo powder and Co powder of 1.3 μm, and Cr powder of 1.7 μm were prepared, and these raw material powders were blended into the composition shown in Table 1. Hard sintered alloys 3 to 9 of the present invention having substantially the same composition as the blended composition were manufactured under manufacturing conditions.

The hard sintered alloys 3 to 9 of the present invention obtained from this result all had a lemon-gold specular color, and their hardness was high as shown in Table 1. Even in a corrosion resistance test under the same conditions as in Example 1, no spider spots were observed on the polished surface, indicating excellent corrosion resistance.

As mentioned above, the alloy of the present invention does not have the same lemon-like golden color tone as conventional TaC-based hard sintered alloys, but has excellent corrosion resistance and high hardness, so it has superior corrosion resistance and high hardness.
It is suitable for use as an alternative material to aC-based hard sintered alloys, for example in the manufacture of decorative parts such as watch sides.
Furthermore, it has industrially useful properties such as being able to be manufactured at low cost using readily available raw materials.

Claims (1)

[Claims] One or two of I Co and Ni: 3 to 3
0%, Mo: 1 to 15%, Cr: 0.2 to 6%, composite metal carbonitride oxide and unavoidable impurities: the remainder (weight%), and the composite metal carbonitride When the oxide is represented by the chemical formula: (TiuMv)CXNyOz, M: Z ryHft Vp Nb, Ta
, one or more of Mo, Cr+ and W;
u 10v = 10.95≦x10y1z≦1.0.4≦
U≦0.995.0.005≦V≦0.6, 0.2≦
X≦0.6.0.4≦y≦0,8, 0,01≦2
A hard sintered alloy for decorative parts, which satisfies the condition of ≦0.1, has excellent sinterability and polishability, and has a lemon-like golden color. 2 One or two of Co and Ni: 3. ~30%, Mo: 1~15%, Cr: 0.2~6%, vanadium carbide 0.1~15%, composite metal carbonitride oxide and unavoidable impurities: remainder. %), and the above-mentioned composite metal carbonitride oxide is represented by the chemical composition formula: (T i us Mv ) CxNyO2, M: Zrt Hfs V, NbtT a y
M op Cr one or more of t and W, u 10v = 1 0.95≦Xfy 10z≦1.0.4≦U≦0.995
．． 0.005≦V≦0.6 0.2≦X≦0.6.
A hard material for decorative parts that satisfies the conditions of 0.4≦y≦0.8, 0.01≦2≦0.1, has excellent sinterability and polishing properties, and has a lemon-like golden color tone. Sintered alloy.