JPS643932B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The disclosed technology belongs to a technology in which cobalt and nickel or nickel is added to a platinum-palladium alloy used for decorative materials such as tie pins to promote processing characteristics. <Summary of the gist> The invention of this application is to improve the workability of a platinum alloy used as a decorative material for rings, tie pins, etc. with respect to a base alloy to which platinum and palladium are added in a predetermined weight percent. This invention relates to a decorative platinum alloy to which small amounts of other elements are added, and in particular, the wt% of platinum and palladium is
-90 wt% and 1 to 20 wt%, and the other small amounts of other added elements are cobalt and nickel, or 0.05 to 10 wt% of nickel alone, respectively, to achieve excellent color tone and hardness. It is. <Prior art> As is well known, gold, silver, platinum, and alloy materials based on these materials are widely used in rings and necklace accessories, and their selection is based on aesthetic characteristics and processing merits. , use conditions and cost are taken into consideration and the selection of use is given. Although these seed platinum alloys are relatively comprehensively superior in the various points mentioned above and are expensive, they are widely used; for example, alloys of 90 wt% platinum to 10 wt% palladium are often used It's been getting worse. By the way, the process by which platinum alloys are processed into decorative material alloys is usually to melt them and then cast them into a predetermined shape, and then to process them as desired, or to reuse them after recasting for precision molding. Therefore, it is desired that the material has the following material properties, including not only aesthetic properties as a decorative material but also processing properties and the like. In other words, (a) the material state is excellent in workability into wires, plates, etc., and (b) when the material is remelted and cast into the desired shape, the melt flow is good and the fine shape is formed. (3) Excellent color tone, gloss, etc. as a decorative precious metal material; (4) Surface hardness to prevent damage to the product. (e) It must have sufficient strength necessary for fixing jewelry, etc. <Problem to be solved by the invention> However, the platinum 90wt%-palladium 10wt% alloy that has been commonly used has the above-mentioned (a), (b),
Although the characteristic (c) is satisfied, there is a problem that the surface is easily scratched or pressed during the polishing process of the casting, which makes polishing difficult and extremely cumbersome. As a result, there are drawbacks such as difficulty in producing gloss, and the finished product also has the disadvantage of being prone to minute wear and tear during use.
It has the disadvantage of being inferior in commercial value compared to other precious metals and gemstones, and for this reason, the above point (d) cannot be satisfied. Furthermore, when a ring pedestal with a stone is processed and jewelry such as diamonds, opals, rubies, etc. is assembled, the stone stopper made of the alloy may become deformed or loosen due to lack of strength due to insufficient hardness, causing the jewelry to fall off. There are some inconveniences, such as point (e).
It was something I couldn't be satisfied with. To supplement this, the above platinum 90wt% - palladium
Decorative platinum alloys are used in which a 10wt% platinum alloy is used as a base alloy and other minor elements such as copper or manganese are added in the range of 1-5wt%, but although hardness can be improved, changes due to oxidation are used. occurs,
In addition, there are disadvantages such as poor castability, cracking of the cast due to inclusion of oxides, and difficulty in remelting debris generated during the polishing process. It was only used in a limited number of ways, and had the drawback of lacking versatility. In response to this, a technology has been developed in which cobalt is added to the base alloy in platinum-palladium based platinum alloys, but when the cobalt content increases, there is a problem that blue discoloration appears on the surface of the cast body. Further, there was an inconvenience that led to the generation of slag during atmospheric heating casting. The purpose of the invention of this application is to solve the technical problem of the material properties of platinum-palladium based platinum alloy based on the above-mentioned prior art, and to
By adding cobalt and nickel in the range of 0.05 to 20 wt% each, or nickel alone in the range of 0.05 to 10 wt% to a base alloy of 1 to 20 wt% palladium, we provide a new decorative platinum alloy with excellent color tone and workability. That is. <Means/effects for solving the problem> In order to solve the above-mentioned object, the structure of the invention of this application, which is summarized in the above-mentioned claims, is to improve the color tone and metallic luster by adding the above-mentioned elements. We have developed a technical means to make this a decorative gold alloy that has excellent material properties such as workability and castability, and also has mechanical and physical properties such as surface hardness, toughness, and springiness when cast. This is what I learned. Therefore, if the amount of platinum added to the base alloy is less than 70% by weight, the color tone and luster will be poor.
In addition, it has a negative effect on workability, and if it exceeds 90%, the hardness becomes inferior.
If the percentage is less than 1wt%, the castability deteriorates, and if it exceeds 20wt%, the workability deteriorates, so the respective ranges are optimized. In addition, cobalt and nickel added to the above base alloy act to enhance the color tone of platinum and palladium-containing gold alloys compared to other elements, improve castability, and further increase hardness. When cobalt and nickel are added together, it is possible to prevent blue discoloration of the surface of the cast body due to an increase in the cobalt content and to make the hardness the same, and also to prevent the occurrence of slag from increasing during atmospheric heating casting. It was found that 0.05wt% or less of each cannot contribute to hardness enhancement, therefore, it does not contribute to the improvement of the platinum-palladium-platinum alloy, and 10wt% or less
If it exceeds this, the color tone due to the blue discoloration described above will worsen,
0.05wt% or more each as there is a risk that the castability will decrease, the hardness will become abnormally high, and the polishing work will become hard.
The optimum range is 10wt%. <Examples> Next, examples of the invention of this application are shown in the following table in comparison with conventional platinum alloys.

[Table] The above values indicate weight %, and each sample was mixed in an amount of 500 g, melted in a normal high-frequency furnace using a magnesia crucible with an inner diameter of 30 mm, and the ingot obtained after melting was cast. It was cut with a saper and rolled with grooves, and used as a 6 mm square rod. The results of material tests conducted on the samples of each of the above examples are as follows. <First test> Collect 150g of each sample in the table above, and
We took 50g each, annealed it, then hard-worked it to a diameter of 0.5mm, and tested to see if the wire would break during that time.All of the work was good, and the processability of the material into wire and plate was excellent. It has been found that the properties of the invention samples of this application are as good as those of the known conventional alloy samples. <Second Test> The remaining part of each of the above samples was cut into pieces of 80 g, and using a well-known high-frequency melting type centrifugal casting machine, rings with square claws (10 pieces per charge) and rings with standing claws were cut into pieces of 80 g. Rings (10 pieces per charge) were cast, and other samples were made into rod-shaped bodies with a diameter of 2 x 100 mm using the same centrifugal casting machine. The ring cast in each of the above processing steps was cooled, removed from the mold, and then subjected to a series of polishing steps such as sanding, spatula, and buffing for finishing. During this time, in each work process, we not only checked the difficulty of workability, but also the color tone of the finished surface, metallic luster, hardness of the finished surface, observation of mold holes in horizontal and vertical sections, and microscopic examination. It has been found that the platinum alloys of the embodiments of the invention of this application have no inferiority in workability and are far superior in finished surface color tone, metallic luster, and hardness, compared to known conventional platinum alloys. In addition, the quality of castability and casting surface were determined by ordinary optical microscopy and X-ray transmission tests, and both the known samples and the invented samples were found to be good. <Third Test> The results of the finished surface hardness test of each of the above ring samples based on the Bitkers hardness test method are as follows, and the platinum alloy of the invention of this application is superior to the conventional alloy. It is clear that good results were obtained.

[Table] <Fourth Test> Tensile strength, elongation, and 90° bending tests were conducted on the above-mentioned φ2xl 100 mm rod-shaped test pieces for each sample. The results showed that the platinum alloy of the embodiment of the invention of this application was better than the conventional alloy. It was. <Fifth Test> In addition, tests similar to those described above were conducted for each example sample with the base alloy being Pt85wt%-Pd15wt%, and the results were substantially the same and satisfactory results were obtained. <Effect of the invention> As described above, according to the invention of this application, platinum 70~
90wt%, palladium 1-20wt base alloy, cobalt and nickel 0.05-20wt each
% or only nickel in the range of 0.05 to 10 wt%, the good workability and castability that are basically required as a decorative alloy are improved compared to the conventional 90 wt% platinum to 10 wt% palladium. %
Therefore, it is effective for various decorative processing, and also has excellent color tone and luster, so it can be used for everyday accessories such as tie pins and cufflinks. Since discoloration due to oxidation does not occur, excellent effects are achieved without the risk of deterioration of the decorative function over time. Furthermore, since the entrainment of oxides is eliminated, casting cracks are also reduced, and castability is also improved, which has the advantage of preventing processing troubles from this point of view. Furthermore, since the surface hardness is superior to that of conventional platinum alloys, the retaining claws of jewelry such as rings will not bend or break and will perform their original function. Effects such as being able to do things are also achieved. Therefore, by adding nickel to cobalt as in the above claims,
Alternatively, by adding only nickel, the intense blue discoloration on the surface of the cast body due to the increase in cobalt content can be suppressed, and the same hardness can be obtained. It has the effect of suppressing the occurrence of slag. Furthermore, the durability of the crucible used during casting is affected by the corrosion of the crucible due to the addition of cobalt, and especially in the case of alumina-based crucibles, the corrosion reaction is large, but this has the effect of improving durability to suppress this corrosion reaction. There is. Additionally, during casting, the addition of nickel has the effect of significantly improving fluidity, and furthermore, adding nickel increases the coefficient of thermal expansion and reduces the shrinkage rate of the cast body. Excellent effects are produced. Further, when only cobalt is added, the cost is 7,000 yen per kg, but by adding nickel, the cost is reduced to 1,500 yen per kg, which is an excellent effect that leads to cost reduction.

Claims (1)

[Claims] 1. A decorative platinum alloy in which other elements are added to a base alloy consisting of platinum and palladium, wherein platinum 70~
A decorative platinum alloy comprising a base alloy consisting of 90 wt% palladium and 1 to 20 wt% palladium, with the addition of nickel in the range of 0.05 to 10 wt%. 2. In decorative platinum alloys made by adding other elements to a base alloy consisting of platinum and palladium, platinum 70~
Base alloy consisting of 90wt%, palladium 1-20wt%, cobalt 0.05-10wt%, and nickel 0.05-
A decorative platinum alloy characterized by containing an additive in the range of 10wt%.