JPS6134133A - 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, Cu, Y, B, calcium boride and misch metal to Pt. CONSTITUTION:The Pt alloy consisting of 84-96wt% Pt, 0.5-10wt% Co, 0.5- 10wt% Cu and at least one among 0.01-0.5wt% each of Y, B, calcium boride and misch metal is manufactured. The Pt alloy has higher hardness and a smaller grain size after annealing than that of a conventional Pt alloy for accessories, and when the alloy is cast, it reproduces more exactly the fine pattern of a casting mold and hardly produces blow holes.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to rings, necklaces, brooches, tie pins, and cuff sprockets, two watch frames, and two watch bands.

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 decorative items such as the above-mentioned P, 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 rings with jewels have the disadvantage that the part that holds the jewels loosens and the jewels fall off.

The latter platinum-palladium-copper alloy has excellent workability and mechanical strength like 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 includes 84 to 96% by weight of platinum, 0.5 to 10% by weight of cobalt, 0.5 to 10% by weight of copper, yttrium, boron, calcium porite,
, mischmetal, each in an amount of 0.01 to 0.5% 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. This is because the amount added is 0.
The reason why it is limited to 5 to 10% by weight is that if it is less than 0.5% by weight, 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 yttrium, The addition of at least one of boron, calcium porite, and misch metal further improves castability, and also increases mechanical strength by preventing coarsening of crystal grains at high temperatures (e.g., during brazing). If the amount added is less than 0.01% by weight, there will be little prevention of coarsening of crystal grains at high temperatures and improvement in castability;
This is because if it exceeds this, workability 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 component compositions shown in column A of the table below, and the reproduction of fine patterns on the molds. The limit, 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 table above, 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 when cast. It can be seen that the fine pattern of the mold is excellent in re-limiting, and the occurrence of cavities is also 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] 84-96% by weight of platinum, 0.5-10% by weight of cobalt,
0.5-10% by weight of copper and 0.01-0% each of yttrium, boron, calcium borite, and misch metal
．． A platinum alloy for decorative articles comprising at least one species in a range of 5% by weight.