JP2011132569A - Platinum alloy and ornament using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem in the conventional platinum alloy such that when hardness increases, castability reduces, and risks occur in the generation of shrinkage cavities accompanying solidification shrinkage upon casting, and the generation of pinholes, cracks or the like caused by gas absorption. <P>SOLUTION: A platinum alloy essentially consisting of Pt, and comprising one or more kinds selected from In, Co and Ni is composed. Further, the Pt is included by 90.0 to 99.6.wt. Further, the In is included by 0.3 to 5 wt.%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a platinum alloy and a decorative article using the same.

  Platinum alloys used as ornaments are soft, easily scratched, low in strength and easy to deform.

  Therefore, in a cast product, a platinum alloy containing elements of In and Pd, Rh, Ir, Ru, Au, Cu has been proposed in order to improve the hardness (see Patent Document 1).

Japanese Patent Laid-Open No. 2005-29879

  However, in Patent Document 1, there is a possibility that a shrinkage nest accompanying solidification shrinkage at the time of casting, pinholes or cracks due to gas absorption, etc. may occur.

  In view of the above, the platinum alloy of the present invention contains Pt as a main component, and contains In and one or more elements selected from Co and Ni.

  Furthermore, the Pt is included in 90.0 to 99.6% by weight.

  Furthermore, the In content is 0.3 to 5% by weight.

  Furthermore, the element is contained in a total amount of 0.1 to 5% by weight.

  Furthermore, the Vickers hardness is 130HV or more.

  The decorative article of the present invention is characterized by using the platinum alloy.

  According to the present invention, containing Pt as a main component and containing In and one or more elements selected from Co and Ni, while maintaining high platinum quality, shrinkage cavities accompanying solidification shrinkage during casting, Generation of pinholes and cracks due to gas absorption can be reduced, and high hardness can be achieved.

  Hereinafter, each embodiment of the platinum alloy of the present invention will be described.

  One embodiment of the platinum alloy of the present invention contains Pt as a main component and contains In and one or more elements selected from Co and Ni.

  Thereby, it is possible to reduce the occurrence of shrinkage cavities due to solidification shrinkage during casting, pinholes and cracks due to gas absorption, and the hardness can be improved.

  This is because the solidification line and the liquidus line in the phase diagram can be widened to increase the time for solidification.

  In one embodiment, the Pt is included in 90.0 to 99.6% by weight.

  Thereby, a high platinum quality can be maintained.

  In one embodiment, the In is included in an amount of 0.3 to 5% by weight.

  In a certain embodiment, the said element is contained 0.1 to 5weight% in total.

  Furthermore, when the element is simple Co or Ni is simple, it is more preferable to contain 2.5 to 5% by weight.

  Moreover, even when the element contains both Co and Ni, it is more preferable to contain 2.5 to 5% by weight.

  Thereby, the hardness can be further improved.

  Further, the occurrence of shrinkage cavities accompanying solidification shrinkage during casting, pinholes and cracks due to gas absorption, and the like can be reduced.

  In some embodiments, the Vickers hardness is 130 HV or higher.

  As a result, while maintaining high platinum quality, it can have high hardness with reduced shrinkage cavities accompanying solidification shrinkage during casting, pinholes and cracks due to gas absorption, etc. It is possible to obtain decorative items that are difficult to stick.

  Furthermore, it is more preferable that the hardness is 180 HV or higher.

  And the ornament of the present invention uses the above platinum alloy, and it can be used for ornaments such as rings, pendants and earrings, as well as watch housings and bands, glasses frames and fountain pen nibs. Can do.

  Next, an embodiment adopted in the production method of the present invention is shown.

(Raw material process)
In the present embodiment, Pt, In, and one or more elements selected from Co and Ni are included in a blending ratio of Pt 90.0 to 99.6% by weight, In 0.3 to 5% by weight, and a total of the above elements of 0.3%. Weigh so that it is 1 to 5% by weight and the total amount is 300 g.

(Melting process)
In this embodiment, the crucible is placed in a high-frequency electric furnace and heated for several minutes, then the raw materials are charged, the furnace is sealed, the inside of the furnace is further evacuated with a vacuum pump, and further 700 to 900 ° C. for several minutes. Heat with vacuum melting.

(Forging process)
Then, pressure is applied to the metal material after the melting step to cause plastic flow, forming and forging.

  As a result, the forged streamlines are continuous, the structure becomes dense, and a cast hole is less likely to be formed than by casting, so that it is possible to produce a rough material having excellent strength.

  In this embodiment, the forged plate is used as an ingot, but forging methods include die forging (forging using a forging die), free forging (a workpiece is set on a jig, a hammer, etc. Can be selected as necessary.

  The types of forging are hot forging (heated to a temperature higher than the recrystallization temperature to reduce the deformation resistance of the material) and cold forging (finished by molding at room temperature below the recrystallization temperature. However, hot forging is used in this embodiment. However, in this embodiment, the hot forging is used.

  Examples of the forging machine include an air hammer, a spring hammer, and a forging press. In this embodiment, a rolling roll is used.

(Casting process)
In this embodiment, the ingot is melted and heated again after the forging step, and centrifugally cast into a ring shape at a casting temperature of 1800 to 1900 ° C. in a mold having a temperature of 800 ° C. produced by the lost wax method.

  After the temperature of the molten metal is raised to nearly 1900 ° C., a molten platinum alloy is poured by applying centrifugal force to a molten quartz mold set so that the molten metal pouring hole is in contact with the pouring hole of the crucible.

  Wait for a while after pouring, and after the platinum alloy melt has solidified, the mold is immediately poured into water and rapidly cooled.

  As the rapid cooling method, any one of air cooling and air cooling may be used, but conditions (time, temperature, etc.) that can most reduce the occurrence of nests may be selected.

(Polishing process)
As the polishing means, a known polishing means such as buff polishing, chemical polishing or a combination of barrel polishing, buff polishing and chemical polishing may be used. In particular, in this embodiment, buff polishing most suitable for ring polishing is used. .

(Inspection process)
In this embodiment, Vickers hardness (Hv) is measured at three locations near the center of the ring surface, and the structure of the ring surface is observed.

  The reason for using Vickers hardness is that it can be used for all metals regardless of the size of the material, and is the most versatile hardness test method.

  This is because the shape of the indentation is similar even when the load changes, and even for different types of materials, hardness can be obtained on the same scale just by changing the load, and there is an advantage that they can be compared with each other Because.

  As an inspection method, you may evaluate by Rockwell hardness, Brinell hardness, and Shore hardness besides this.

Example 1
An ingot was produced by forging at 800 ° C. using a rolling roll after vacuum melting a Pt—In—Co—Ni alloy in which the total amount of In, Co, and Ni was adjusted with respect to 300 g of Pt as a main component.

  120 g of this bare metal was set in a mold heated to 800 ° C., and centrifugally cast into a ring shape by a lost wax method at a casting temperature of 1830 ° C. (Samples 2 to 6, 16 to 19).

(Example 2)
An ingot was produced by forging treatment at 800 ° C. using a rolling roll after vacuum melting a Pt—In—Co alloy in which the total amount of In and Co was adjusted with respect to 300 g of Pt as a main component.

  A mold in which 120 g of the ingot was heated to 800 ° C. was set, and was cast into a ring shape by a lost wax method at a casting temperature of 1850 ° C. (Samples 8 to 11).

(Example 3)
An ingot was produced by forging treatment at 800 ° C. using a rolling roll after vacuum melting a Pt—In—Ni alloy in which the total amount of In and Ni was adjusted with respect to 300 g of Pt as a main component.

  A mold in which 120 g of the bare metal was heated to 800 ° C. was set, and was cast into a ring shape by a lost wax method at a casting temperature of 1880 ° C. (samples 12 to 15).

  On the other hand, a Pt—Co—Ni alloy (sample 1) and a Pt—In alloy (sample 7), which were centrifugally cast into a ring shape by the lost wax method, were prepared in accordance with Examples 1 to 3 above.

(Evaluation methods)
As described above, the ring castings of Samples 1 to 19 were buffed, and the Vickers hardness (Hv) was measured at three locations near the center of the ring surface.

  In addition, shrinkage nests, pinholes, and cracks were confirmed at three locations on the ring surface with a factory microscope (20 ×), and the structure of the ring surface was observed.

  The results are shown in Table 1.

  In the external appearance evaluation of Table 1, ◯ indicates good, Δ indicates usable, and x indicates unusable.

  In Sample 1, since In was not contained, the castability was inferior and the appearance was not satisfied, and the hardness was not satisfied.

  Sample 7 did not contain Co or Ni, so the appearance resulting in poor castability was not satisfactory.

  On the other hand, the other samples 3, 4, 5, 8, 9, 10, 12, 13, 14, 16, 17, 18 were able to obtain sufficient characteristics.

  Sample 2 contained a small amount of In and had a low hardness, but was in a usable range without problems in actual use.

  Sample 6 has a small total amount of Co and Ni, and samples 11, 15, and 19 have a large total amount of Co and Ni. Therefore, castability was slightly inferior, but the appearance was affected. It was a range.

  As described above, according to the present invention, by controlling one or more elements selected from In, Co, and Ni, high platinum quality is maintained, shrinkage nests accompanying solidification shrinkage during casting, and pins due to gas absorption Generation of holes and cracks can be reduced, and high hardness can be achieved.

  As a result, in addition to ornaments such as rings, pendants, and earrings, it can be suitably used for products that require hardness and castability, such as watch housings and bands, eyeglass frames, and fountain pen nibs. .

Claims (6)

  A platinum alloy containing Pt as a main component and containing In and one or more elements selected from Co and Ni.   The platinum alloy according to claim 1, wherein Pt is contained in an amount of 90.0 to 99.6% by weight.   The platinum alloy according to claim 1 or 2, wherein the In is contained in an amount of 0.3 to 5% by weight.   The platinum alloy according to any one of claims 1 to 3, wherein the elements are contained in a total amount of 0.1 to 5% by weight.   The platinum alloy according to any one of claims 1 to 4, wherein the Vickers hardness is 130HV or more. An ornament using the platinum alloy according to any one of claims 1 to 5.