DE2401983A1 - HARD ALLOY FOR JEWELRY PURPOSES AND THE LIKE - Google Patents

Description

DipI.-It-.g. H: .iri7. Lesser, Poler.tcnvciU D - 8 Munich S1, Cosimastraße Si · Tti ^ 'o · »: (GSlI) 95 3ε 2C j

Nippon Tungsten Co., Ltd. 2401983 j

460 Aza Sanno, Oaza Shiobaru j

Minami-ku, Fukuoka-shi
Fukuoka-ken, Japan L 10.252 / Fl / ost

The invention relates to a hard alloy for jewelry purposes and the like. With one or more sintered materials Metals from groups IV, V and VI of the periodic table of the elements and a binder that contains elements of the iron family.

There are decorative alloys, for example for the finishing of objects such as clocks, known that by conventional Powder metallurgy process can be produced. Metcillkarbide (cemented carbides), which are obtained by using carbides of a metal contained in periodic groups IV, V and VI are bound with elements of the iron family, which are achieved in particular by binding tungsten carbide particles with cobalt, are due to their high scratch resistance and their semi-permanent high gloss or shimmer. As a decorative material (decorative material) such as for Example as a watch case, well suited.

However, the metal carbides of this type have a problem that they have insufficient corrosion resistance.

The invention aims to provide an alloy of the type mentioned at the outset which is substantially corrosion-resistant

Hard alloy for jewelry and the like

409830/0842

Dipl.-Icg. Heinz Leaser, Poti> r.tcr.r.cit Z ~ 8 Mincher. 31, Ccimosticfle 8 'Telephone: (0811) 95 38 20

-2-more resistant than the known alloys.

This is achieved according to the invention by using 50-95% by volume of one or more types of boride compositions from the groups vanadium, niobium, tantalum, chromium, molybdenum and tungsten boride and by using 5-50% by volume of a binder one or more kinds of metals from groups of nickel, cobalt and iron, the latter binder is up to 50 vol% replaced by one or more kinds of one or more members of the group ¹ of chromium, molybdenum and tungsten.

The hard borides thus become the periodic ones from the metal borides Groups V-B (V, Nb and Ta) and IV-B (Cr, Mo and W) are selected. The binder includes besides one or more Elements of the iron series include one or more members of the group containing chromium, molybdenum and tungsten.

The decorative alloy according to the invention from the specified percentages from 50-95% by volume of one or more types of the specified hard boride compositions and from 5-50% by volume of a binder with one or more metals from the group of nickel, cobalt and iron, which are 0-50% off. one or more Kinds of one or more members of a group composed of chromium, molybdenum and tungsten, is not only very hard, she. also has the desired excellent corrosion resistance.

In the present invention, one or more types of borides made of vanadium, niobium, tantalum, chromium, molybdenum and tungsten, because such borides have a good bond (Ground connection) to the binder during the sintering process and at the same time a much better corrosion resistance than those obtained by using different carbides.

409830 / Ü842

Dipl.-lriQ. Heinz lossei, Patentonwult

D -8 Munich 81, CosUnailioße 81 · Telephone: (0811) 96 3b 20

-3-

The binder used according to the invention should be 5-5Ο vol% the alloy mixture can be limited. This range was established experimentally by the fact that binders of less than 5% has a relatively low deflection of the sintered products and, on the other hand, that binders of more than 50% result in products of low hardness so that the use of binders outside the above limitation is impractical.

To ensure the corrosion resistance of the targeted products, as well To improve the binding properties, chromium molybdenum, tungsten or a combination thereof is added to the binding agent and up to 50% by volume. This limit was established in extensive experiments which demonstrated the fact that more as a 50% addition, a deterioration in the deflection capacity of the sintered products.

Example:

Six kinds of boride particles and the same number, of Binder particles are used as raw materials to make the hard alloys of the present invention. The grain size of the material is shown in Table 1.

TABLE 1

chemical formula Grain size Boride VB ₂ , N ₆ B, TaB ₂ -325 mesh CrB, MoB ₂ , IiB binder Ni. · 1.3 microns Co ld " Fe -200 mesh Cr 4 x 5 microns - Mon I08 " W. 1ο2 "

£ 09830/0842

Dipl.-Ing. Heim Lesser, Potentanv / olt U - b iV-undien 81, CosimostraGe 81 · Telephone: (C811J 95 3S 20

-4-

The boride particles were mixed with the binding particles, to form a mixed amount, which is shown in Table 2 below.

The procedure was as follows: Mix a quantum by wet blending for 100 hours; Treatment in a ball mill; Dry; Adding 5% by volume of camphor as a lubricant; Input in a shape of 10 χ 30 χ 30 mm; under the pressure of 1 t / cm; For 1 hour, sintered at a temperature of 1400 ° C in vacuum (only 95 MoB ,,. I Ni-Mo alloy was sintered for 1 hour at a temperature of 1500 ⁰ C.).

The hardness and corrosion-resistant properties of all alloys prepared according to the above example are in the Table 2 indicated in which a 70WC-30CO alloy for the purpose Comparison with the present alloys was added.

As shown in the table, all of the alloys of the present invention had a hardness higher than 70WC-30CO metal carbide and showed an excellent shimmer after fine grinding (lapping). Furthermore, they showed a better one Corrosion resistance to alkali than the hard alloys currently available.

Since, as discussed above, all of the alloys of the present invention have a comparatively high hardness and excellent scratch resistance and their gloss is stable they are widely used in the manufacture of ornamental products including watch cases.

As many different embodiments of the invention are possible Without departing from the spirit and scope of the invention, it is to be understood that the invention is not limited to the specific

409830/0842

Dipl.-Ing. Heinz Lesser, patent attorney D -8 Munich 81, Cosimostraße 81 · Tdofon: (0811) 95 3fS 20

Embodiments defined in the claim is limited.

409830/0 8 42

TABLE 2 Hardness and Corrosion Resistant Properties

Alloy composition (Vol%) ', · ■ · \ binder Ni Co Fe ·. Cr Mon W. I. 10 . 10 10 hardness
(HV) j
I i ι , ⁵ 147Ο Corrosion Resistant. Properties in
Compared to a 70WC-30CO alloy 8 hours in 30%
NaOH solution (20 c) ... Hard alloy 30th 10 5 1215- 1373 8 hours in 30%
HNO3 solution (20 ° C) Carbide has been etched 70WC 30th • 10 ■ 5 I433 ■ 20! 1269 Binder has been etched + + 60VB ₂ 30th 5 I4I7 1 ί. · 1436 + + + + + 60NbB 30th 10 5 I39O 1412 ,. + + + ¹ ■ + + + '... 6OTaB ₂ 15th 15th I382 ! 1273 + + + ■ + 6OCx-B 15th 15th 5 1266 1512 + + 6OMoB ₂ 10 10 10 y '5 10 5 Il 1295 1543 ■ + + . + ■ 60WB ^; 30th 10 + + + + 30VB ₂ -30NbB 30 " ■ · ++. + + + . 3OTaB ₂ -3OCrB 30th 10 · ■ · + + + 30MoB ₂ -30WB 30th 20VB, -2OTaB., - 20MoB,
tL / L <L 10 10 + + + + + > o 20N ^T bB-20CrB ~ 20WB 40 + + JL. JL. Z) 5OtO 20th 1
I ++ + + 1 60VB 4th + + * + + ' 9SMoB ₂ !
• i- + +

+ better than 70WC-30CO alloy

++ slightly better than 70WC-30Co alloy (little etching) +++ significantly better than 70WC-30CO alloy (no etching)

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Table 2 Hardness and. Anti-corrosive property

O CD 00 CjO O

Alloy composition {% by volume) · ■ Ni Co Fe Cr Mon • 5 W. Hard
ness
(HV) Anti-c®rrosive property compared '
with 7OWC-3OC0 alloy 8 hours in 30 ^
NaOH solution (20 ° E • Hard alloy 30th 5 1215 8''h'ours in 30%
ENT solution (20 ° C) Carbide was etched 70WC 30th 10 1483 Binder was etched _{+ +} 60VB ₂ 30th 10 1417 + + +. 6ONbB 30th 10 10 1390 _{+ + +} - + + ₊ 60TaB ₂ 15th 15th 5 1382 _{+ + +} 6OCrB 15th 15th 5 10 1266 + +. + " 6QMoB ₂ 10 10 10 5 .5 5 1295 . + 60WB ' 30th 10 10 1470 ■ + + 30VB ₂ -30NbB 30 ' 20th 1373 + + ■. ■ 30TaB ₂ -30CrB 30th 10 1 1269 _{+ + +} + 30MoB ₂ -30WB 30th 1436 20VB "-20TaB" -20MoB. 10 10 10 5 1412 • _{+ + +} 20NbB-20CrB-20WB 40 1273 + + 5OVB ' 20th 1512 + + 60VB 4th ·· 1543 + + ■ + + + 95MoB ₂

~ Better than 70WC-3Q Co alloy ■

-ί- -r Fairly better than 70W> 30Co alloy (little etching) . + + + 'Significantly better than 7OWC-3CC0 alloy (no etching)

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Claims (1)

PATENT CLAIM Sintered materials of one or more metals from groups V and VI of the periodic table of elements and a binder, which has shares of one or more elements of the iron family, characterized by 50-95 vol% one or more types of boride compositions from the group of vanadium, niobium, tantalum, chromium, molybdenum and Tungsten boride and by 5-50 vol% of a binder with a or several types of metals from the group of nickel, j cobalt and iron, which latter binder up to ζ χα 50 vol% is replaced by one or more kinds of one or more members of the group of chromium, molybdenum and tungsten. 409830/0842