JPS61133340A - Platinum alloy for ornament - Google Patents

Abstract

PURPOSE:To improve the workability, mechanical strength, and castability of the alloy for ornaments, by incorporating specific amounts of Ga, Cu, Mn, and Co to Pt. CONSTITUTION:The Pt alloy for ornaments consists of, by weight, 84-96% Pt, 1-10% Ga, 0.5-10% Cu, and 0.01-5%, each, of >=1 kind among Mn and Co. In this alloy composition, Ga does not react with a mold at casting and satisfies the requirements for the control of concentration of oxygen at casting, Cu improves mechanical strength, and Mn and Co improve castability and inhibit the coarsening of the grains at high temp. This Pt alloy excels in reproducibility of casting and can be used for rings, necklaces, brooches, tiepins, watches, and the like.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to rings and necklaces. Brooches, tie pins, cufflinks, and one watch band.

This invention relates to the improvement of platinum alloys used as materials for lighters, writing utensils, eyeglass frames, earrings, etc.

(Prior art and its problems) Conventionally, a platinum-palladium (5-15 weight %) alloy is often used as a material for the above-mentioned ornaments, and a platinum-palladium-copper alloy is used.

However, although the former platinum-palladium (5-15% by weight) alloy has excellent workability and castability, it has low mechanical strength, especially hardness, and is easily scratched and stamped during polishing, and its luster is poor. It is hard to come out, and it is also easy to get scratched when used as a finished product (Also, in the case of rings with jewels, the part that holds the jewels loosens and the jewels fall off).

The latter platinum-palladium-copper alloy has excellent workability and mechanical properties as well as the platinum-palladium alloy, but because it reacts with the mold during casting, fine patterns do not appear. The problem was that the image became unclear, and that cavities were formed because the oxygen concentration could not be suppressed.

(Objective of the Invention) The present invention has been made in order to eliminate the above-mentioned drawbacks, and aims to provide a platinum alloy for ornaments that is excellent in not only workability but also mechanical strength and castability. It is.

(Structure of the Invention) The platinum alloy for ornaments according to the present invention contains 84 to 96% by weight of platinum, 1 to 10% by weight of gallium, 0.5 to 10% by weight of copper, and 0.01 to 5% by weight of each of manganese and cobalt. It consists of at least one type within the range of.

The reason why gallium is added to the platinum alloy for ornaments according to the present invention is that it satisfies the conditions of not reacting with the mold during casting, suppressing oxygen concentration during casting, and improving mechanical strength and castability. This is because the amount added is 1~
The reason why it is set at 10% by weight is that if it is less than lii%, improvements in mechanical strength and castability will be low, and if it exceeds 10% by weight, workability will be significantly reduced.

The reason why copper is added is to harden and further improve the mechanical strength; if it is less than 0.5% by weight, the effect will not be fully manifested, and if it exceeds 10% by weight, the workability will deteriorate, and manganese The addition of at least one kind of cobalt in the range of 0.01 to 5% by weight each further improves castability, and also prevents coarsening of crystal grains at high temperatures (for example, during brazing), thereby improving mechanical performance. If the amount added is less than 0.01% by weight, it will hardly prevent grain coarsening at high temperatures and improve castability, and if it exceeds 5% by weight, it will not be processed. This is because the sex becomes worse.

(Examples and Conventional Examples) Reproduction of the hardness and fine patterns of the molds of the platinum alloys for ornaments of Examples 1 to 4 and the platinum alloys for ornaments of Conventional Examples 1 and 2 having the composition shown in the left column of the table below. The degree of occurrence of cavities, and the size of crystal grains were measured after annealing, and the results shown in the right column of the table below were obtained.

(Left below) As is clear from the above table, the platinum alloy for ornaments according to the present invention has superior hardness after annealing compared to conventional platinum alloys for ornaments, has smaller crystal grains, and has a higher hardness than conventional platinum alloys for ornaments. It can be seen that the degree of reproduction of the fine patterns of the mold is excellent, and the degree of occurrence of nests is low.

(Effects of the Invention) As detailed above, the platinum alloy for ornaments of the present invention has extremely excellent workability, mechanical strength, and castability, so it can be used as a substitute for conventional platinum alloys for ornaments. It can be said that it is temporary.

Claims (1)

[Claims] Platinum 84-96% by weight, Gallium 1-10% by weight, Copper 0
．． 5-10% by weight and 0.0 each of manganese and cobalt
A platinum alloy for decorative articles comprising at least one species in the range of 1 to 5% by weight.