Invisible fastness anti-tarnishing layer for silver coin surface and preparation method

A silver coin and aluminum target technology, which is applied to coins, ion implantation plating, applications, etc., can solve the problems of short protection time, changing the metal texture of silver coins, and being invisible, achieving low cost, maintaining the metal texture, and simple and easy process operation line effect

Active Publication Date: 2011-11-02
沈阳中钞造币技术研究有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] The present invention aims at the problems existing in the above-mentioned prior art, has carried out a large amount of groping and test summary, has developed a kind of silver coin surface invisible anti-tarnish protective layer, solves the problem that the anti-tarnish protective layer in the prior art changes the metallic texture of silver coin or Not completely invisible, resulting in unsatisfactory appearance quality of silver coins and short protection time, and the invention is simple and easy to operate, reducing production costs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The preparation method of the aluminum oxide invisible anti-tarnish protective layer on the surface of the silver coin is realized through the following steps: (1) cleaning of the silver coin: at room temperature, the silver coin is ultrasonically cleaned in absolute ethanol for 2 times, each time for 5 minutes, and the second cleaning After the completion, dry the silver coins with hot air; (2) put the silver coins into the vacuum chamber, and vacuum the back to 0.005Pa; (3) Clean the aluminum target: pass high-purity Ar gas with a purity of 99.99% into the vacuum chamber , so that the air pressure is 0.4Pa, a 700V negative bias is applied on the magnetron sputtering target, the excitation current is changed in sequence according to 500, 400, and 300mA, the sputtering current is 400mA, and each excitation current is cleaned for 20 minutes to ensure the surface of the aluminum target The natural oxide film of the silver coin is removed by sputtering cleaning. The purity ...

Embodiment 2

[0029] The difference between this implementation step and Example 1 is that implementation step (4) deposits the invisible aluminum oxide protective layer: the silver coin is heated to 300°C, the baffle plate in front of the aluminum target is removed, and Ar gas and O are introduced into the vacuum chamber. 2 Gas mixed gas, the gas flow ratio is 10:1, the vacuum chamber pressure is 0.3Pa, a 300V negative bias is applied on the magnetron sputtering target, the excitation current is adjusted to 500mA, the sputtering current is 400mA, and the deposition time is 1min, a negative bias of 50V was applied to the silver coin during the deposition process. Other steps are the same as in Example 1.

Embodiment 3

[0031] The difference between this implementation step and Example 1 lies in the implementation step (4) deposition of an invisible aluminum oxide protective layer: the silver coin is heated to 400 ° C, the baffle in front of the aluminum target is removed, and Ar gas and O are introduced into the vacuum chamber. 2 Gas mixed gas, the gas flow ratio is 10:1, the vacuum chamber pressure is 0.3Pa, a 1000V negative bias is applied on the magnetron sputtering target, the excitation current is adjusted to 500mA, the sputtering current is 400mA, and the deposition time is 3min, a negative bias of 50V was applied to the silver coin during the deposition process. Other steps are the same as in Example 1.

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PUM

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Abstract

The invention relates to a silver coin surface invisible tarnish resisting protective layer and a preparing method thereof, and solves the problem that the surfaces of silver coins are discolored after being placed for a long time. The preparing method is realized by the steps: (1) pretreatment of the silver coins; (2) vacuum-pumping; (3) aluminum target cleaning; (4) preparing an aluminum oxide protective layer by reaction magnetron sputtering; (5) aluminum target post treatment. The invisible aluminum oxide protective layer prepared by the invention has good tarnish resisting effect, protects the appearance quality of the silver coins and is long in guard time.

Description

technical field [0001] The invention relates to a protective layer formed on the surface of a silver coin and a preparation method thereof, in particular to an invisible anti-discoloration protective layer on the surface of a silver coin and a preparation method thereof, belonging to the anti-discoloration technology of silver coins. Background technique [0002] When silver and silver alloys are used in an atmospheric environment, a dark adhesion film will be produced on the surface due to atmospheric corrosion. The so-called atmospheric corrosion is a phenomenon caused by a thin layer of corrosive electrolyte attached to the surface of a metal material. The electrolyte is mainly composed of the relative humidity of the air and the ppb level of H 2 S. NO 2 , HCl, SO 2 , O 3 , Cl 2 , ammonia and other organic gases. Usually the discoloration of metals under natural atmospheric conditions is caused by the erosion of the above media. [0003] The discoloration of silver...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C14/08C23C14/34C23C14/54C23C14/58A44C21/00
Inventor 董江赖茂明张吉刚孙立军毕程孙志国
Owner 沈阳中钞造币技术研究有限公司
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