RU2751061C1 - Alloy based on 585-grade platinum - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, in particular to platinum-based alloys designed for the manufacture of jewelry. The platinum-based alloy contains, wt.%: platinum 58.5-59.0; gold 10.0-14.5; zinc 3.1-6.4; ruthenium 0.001-0.01; titanium 0.005; silver is the rest.

EFFECT: invention is aimed at obtaining a jewelry alloy based on 585-grade platinum, which does not contain nickel, with high mechanical properties.

1 cl, 2 tbl

Description

The present invention relates to the field of metallurgy of platinum-based alloys for jewelry making.

In connection with a significant increase in demand and the level of prices for jewelry made from palladium-based alloys and a decrease in the cost of platinum, it is important to create 585-carat alloys on its basis. Since nickel is allergic to direct and long-term contact with human skin and the EU Directive 76/769 / EEC prohibits its use in jewelry, it is necessary to create nickel-free alloys.

Known alloy (RF Patent No. 2650220, C22C 5/04, 04/11/2018), which has a high level of plastic properties. However, the content of palladium in its composition is in the range of 25.0-35.0 wt. % due to its high cost leads to a significant increase in the cost of jewelry made from it.

Closest to the invention is an alloy of platinum 585 (RF Patent No. 2645624, C22C 5/04, 02/26/2018), containing the following components wt. %: platinum 58.5-59.0; palladium 2.9-3.1; zinc 6.5-7.5; silver 14.6-15.6; copper rest. It is suitable for microfusion, has good ductility at a sufficiently high hardness. However, its use also leads to a significant increase in the cost of jewelry.

The main objective of the invention is to create a new nickel-free alloy based on platinum 585, which has an increased level of mechanical properties, expanding the scope of the alloy in the manufacture of jewelry, and having a lower cost.

To solve this problem, a platinum-based alloy containing gold, silver, zinc is proposed, additionally containing ruthenium and titanium with the following ratio of components, by weight. %:

Platinum 58.5-59.0 Gold 10.0-14.5 Zinc 3.1-6.4 Ruthenium 0.001-0.01 Titanium 0.005 Silver rest

The platinum content in the alloy is due to the 585 fineness.

The introduction of gold into the alloy increases the ductility and strength properties.

The introduction of 1.0 to 2.0% zinc into the alloy increases its fluidity, which favorably affects the nature of plastic deformation. When the zinc content in the alloy is above 2%, the brittleness threshold increases, which negatively affects the deformation of the alloy.

Silver within the claimed limits lowers the melting point of the alloy and increases its ductility.

Ruthenium significantly increases hardness and, with its introduction, the alloy has a lower tendency to weld and form needles.

The addition of titanium, with its significant solubility in platinum, increases the hardness. The joint introduction of titanium, silver and ruthenium increases the corrosion resistance of the alloy.

The alloy was obtained by direct fusion of the main components in an induction furnace in an inert gas (argon) atmosphere. The introduction of ruthenium was carried out in accordance with the known method of modifying alloys based on gold (RF Patent No. 2507284, C1 C22C 5/02 C22C 1/03, 02/20/2014) - before crystallization of the alloy in the form of a silver-ruthenium ligature obtained by the deposition of ruthenium from the electrolyte by galvanic way for silver. The temperature range of the alloy was determined by the method of differential thermal analysis. The composition of the alloy was controlled by quantitative chemical analysis.

For comparison, table 1 shows the compositions of the claimed and known alloys, in table 2 - microhardness of alloys in the cast state.

The obtained jewelry alloy of platinum corresponds to 585 fineness, has a beautiful color shade, microhardness sufficient for making jewelry.

The use of the inventive alloy in comparison with the known ones gives no less pronounced modifying effect and thereby makes it possible to increase the mechanical and technological properties of the alloy, while reducing its cost, and to use it in the manufacture of jewelry using methods of metal forming and casting.

Claims (4)

A platinum-based alloy containing silver, zinc, characterized in that it additionally contains gold, ruthenium and titanium in the following ratio of components, wt. %: platinum 58.5-59.0 gold 10.0-14.5 zinc 3.4-6.4 ruthenium 0.001-0.01 titanium 0.005 silver rest