Joint coating copper-based alloy for silver and preparation method thereof

Abstract

The invention provides a joint coating copper-based alloy for silver and a preparation method thereof. The copper-based alloy comprises the following components by weight percent: 3-35% of Zn, 0.5-10% of Sn, 0.1-5% of Si, 0-0.1% of B and/or Li, 0.1-2% of In and the balance of composite rare earth elements and Cu. The composite rare earth elements in the copper-based alloy comprise the following components by weight percent: 0.5-5% of Y and 0-2% of La and/or Ce, wherein the contents of La and Ce are not both zero. One of B and Li is selected. The copper-based alloy uses the composite rare earth elements and various elements with oxygen activities to perform multi-component alloying so as to improve the structure of the alloy, refine grains, degas, clean the grain boundary and increase the mechanical properties, castability and machinability. In addition, the alloy does not contain precious metal elements and has lower cost.

Description

technical field [0001] The invention relates to the field of metallurgy, in particular to a silver-used copper-based alloy for making silver ornaments and a preparation method thereof. Background technique [0002] 925 sterling silver is currently the most widely used jewelry silver alloy material. 925 sterling silver jewelry actually adds 7.5% alloying elements to pure silver, which improves the luster, brightness and hardness of silver. All silver jewelry on the market uses 925 as the standard for identifying whether it is sterling silver. The types of jointing alloys currently added mainly include nickel-based alloys, manganese-based alloys, cobalt-based alloys and copper-based alloys. Nickel-based alloys have good plasticity and medium strength, and are often added with refractory metals such as W and Mo, but the nickel-based alloys have poor corrosion resistance. The high-temperature oxidation resistance and corrosion resistance of manganese-based alloys are poor, and...

AI Technical Summary

Problems solved by technology

However, this alloy has two very prominent problems: one is sulfide discoloration, and the other is the formation of oxidized erythema

However, for silver alloys, the addition of rare earths is often an uncontrollable factor. Since the amount of rare earths added should not be too high, and rare earth elements have extremely high activity, rare earth elements are usually added under non-vacuum conditions in the field of jewelry production. It is difficult to control the burning loss rate of rare earth elements, so it is necessary to study a master alloy containing rare earth elements