【発明の詳細な説明】[Detailed description of the invention]
本発明は、指輪、ネツクレス、ブローチ、ネク
タイピン、カフスボタン、時計枠、時計バンド、
ライター、筆記具、眼鏡枠、イヤリング等の材料
として使用する白金合金の改良に関するものであ
る。
従来、上述の如き装飾品の材料としては白金−
パラジウム（５−15重量％）合金が多用され、そ
の他白金−パラジウム−銅合金が使用されてい
る。然し乍ら前者の白金−パラジウム（５−15重
量％）合金は加工性、鋳造性に優れているが、機
械的強さ特に硬さが低い為研磨中にすり傷、押傷
が付き易く且つ光択が出にくく、また完成品とし
て使用している場合も傷が付き易く、また宝石付
指輪の場合、宝石を止めている部分がゆるんで宝
石が脱落するという欠点があつた。
また後者の白金−パラジウム−銅合金は、前記
白金−パラジウム合金と同様加工性に優れ、その
上機械的強さにも優れているが、鋳造時に鋳型と
反応する為、細かい模様が現われず、不鮮明にな
り、しかも酸素濃度を抑制できないため鋳巣が生
じるという欠点があつた。
本発明は上記欠点を解消せんが為になされたも
のであり、加工性は勿論のこと機械的強さ、鋳造
性に優れた装飾品用白金合金を提供せんとするも
のである。
本発明による装飾品用白金合金は、白金84〜96
重量％、コバルト１〜10重量％、残部銅よりなる
ものである。
本発明による装飾品用白金合金に於いて、コバ
ルトを添加した理由は、鋳造時に鋳型と反応しな
いこと及び鋳造時に酸素濃度を抑制できることの
条件を満し、機械的強さ及び鋳造性を向上させる
為であり、その添加量を１〜10重量％としたのは
１重量％未満では機械的強さ及び鋳造性の向上が
低く、10重量％を超えると加工性が著しく低下す
るからである。
また銅を添加したのは、硬化して一層機械的強
さを向上させる為である。
以下本発明による装飾品用白金合金の効果を明
瞭ならしめる為に実施例、従来例及び比較例につ
いて述べる。
下表の左欄に示す成分組成の実施例１〜７の装
飾品用白金合金と従来例８〜14及び比較例15、16
の装飾品用白金合金の硬さ、鋳型の細かい模様の
再現度、及び、巣の発生度合いについて、夫々焼
なまし後に測定したところ、下表の右欄に示すよ
うな結果を得た。
The present invention includes rings, necklaces, brooches, tie pins, cufflinks, watch frames, watch bands,
This invention relates to the improvement of platinum alloys used as materials for lighters, writing utensils, eyeglass frames, earrings, etc. Conventionally, platinum has been used as a material for decorative items such as those mentioned above.
Palladium (5-15% by weight) alloys are often used, and platinum-palladium-copper alloys are 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, so it is easily scratched and pressed during polishing, and is difficult to select. It is difficult for the ring to come out, and it is easily scratched when used as a finished product, and in the case of a ring with a jewel, the part that holds the jewel in place loosens, causing the jewel to 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 it became unclear and that cavities were formed because the oxygen concentration could not be suppressed. 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. The platinum alloy for ornaments according to the present invention has platinum 84 to 96
% by weight, 1 to 10% by weight of cobalt, and the balance copper. 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 reason why the amount added is 1 to 10% by weight is that if it is less than 1% by weight, the improvement in mechanical strength and castability will be low, and if it exceeds 10% by weight, the workability will be significantly reduced. The reason why copper is added is to harden and further improve mechanical strength. Examples, conventional examples, and comparative examples will be described below in order to clarify the effects of the platinum alloy for ornaments according to the present invention. Platinum alloys for ornaments of Examples 1 to 7, conventional examples 8 to 14, and comparative examples 15 and 16 with the component compositions shown in the left column of the table below.
The hardness of the platinum alloy for ornaments, the reproduction of fine patterns in the mold, 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.
【表】
上記表で明らかなように本発明による装飾品用
白金合金は、従来の装飾品用白金合金に比し焼な
まし後の硬さが優れ、鋳造した際の鋳型の細かい
模様の再現度合も極めて優れていることが判る。
以上詳記した通り本発明の装飾品用白金合金
は、加工性、機械強さ、鋳造性が極めて優れてい
るので、従来の装飾品用白金合金にとつて代わる
ことのできる画期的なものと言える。[Table] 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 reproduces the fine patterns of the mold when cast. It can be seen that the quality is also extremely good. As detailed above, the platinum alloy for ornaments of the present invention has extremely excellent workability, mechanical strength, and castability, so it is an epoch-making product that can replace conventional platinum alloys for ornaments. I can say that.