JPS6134135A - Platinum alloy for accessory - Google Patents

Abstract

PURPOSE:To obtain a Pt alloy for accessories having superior workability, mechanical strength and castability by adding specified percentages of Co, Au, Ag, Rh, Ru and Ir to Pt. CONSTITUTION:The Pt alloy consisting of 84-96wt% Pt, 0.5-10wt% Co and 0.5-14wt% in total of at least one among Au, Ag, Rh, Ru and Ir is manufactured. The Pt alloy has higher hardness after annealing than that of a conventional Pt alloy for accessories, and when the alloy is cast, it also reproduces more exactly the fine pattern of a casting mold.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to rings, necklaces, brooches, tie pins, cufflinks, and watch frames and clock hands.

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, platinum-palladium (5-15% by weight) alloy is often used as a material for the above-mentioned ornaments, and platinum-palladium-copper alloy is also 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. They are difficult to remove and are easily scratched when used as a finished product, and in the case of rings with jewels, the part that holds the jewels in place 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.

(Object of the Invention) The present invention was 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. be.

(Structure of the Invention) The platinum alloy for ornaments according to the present invention contains 84 to 96% by weight of platinum, 0.5 to 10% by weight of cobal, and gold and silver.

The total amount of at least one of rhodium, ruthenium, and iridium is 0.5 to 14% by weight.

The reason why cobalt 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. The purpose is to improve the
．． The reason why the content is 5 to 10% by weight is that if it is less than 0.5% by weight, the improvement in mechanical strength and press castability will be low, and if it exceeds 10% by weight, a large amount of cobalt oxide will be generated in the melting and holding process, resulting in poor casting performance. This is because when the oxide is mixed in, the product yield is reduced.

Furthermore, the addition of at least one of silver, gold, rhodium, ruthenium, and iridium suppresses the amount of coimalt oxide generated during melting and melting, and increases mechanical strength without reducing product yield during casting. This is to improve the
If the amount added is less than 0.5% by weight, the improvement in mechanical strength will be low, and if it exceeds 14% by weight, it will have the effect of suppressing the amount of cobalt oxide generated, but the processability will deteriorate.

(Examples and Conventional Examples) The hardness of the platinum alloys for ornaments of Examples 1 to 4 and the platinum alloys for ornaments of Conventional Examples 5 and 6 with the compositions shown in the left column of the table below, and the reproduction of fine patterns on the molds. The limits and the degree of occurrence of cavities 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, and the fine patterns of the mold when casting are improved. It can be seen that the degree of reproducibility is also extremely excellent.

(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] 84-96% by weight of platinum, 0.5-10% by weight of cobalt,
and a platinum alloy for ornaments containing at least one of gold, silver, rhodium, ruthenium, and iridium in a total amount of 0.5 to 14% by weight.