The discoloration reason of silver plated copper wire

1.The Influence of Sulfide and Halide in the Air

The chemical properties of silver are relatively active in the normal temperature environment, and it is easy to react with substances such as hydrogen sulfide when exposed in the air, so that the silver layer becomes dark and black to produce silver sulfide and so on. Silver sulfide not only affects the surface appearance of the silver layer, but also seriously affects the welding performance of the product and the signal transmission in the high frequency radio frequency cable, it will even increases the surface resistance of the silver coating.

2.The Influence of High Temperature and High Humidity Environment in the Air

For many years, it has been found in the production process of the workshop that the surface color change of silver plated copper wire is more serious than that of other seasons when it is hot and rainy in summer. At the beginning, the surface of silver-plated copper will turn red. As time goes by, the surface of silver-plated layer begins to turn black. After analysis, the red substance on the surface of the silver layer is cuprous oxide, and the black substance is copper oxide. It is easy to form a layer of water film on the surface of the silver layer in humid environment. Because the metal potentials of copper and silver are different, the surface of metal generates corrosive micro-batteries under the effect of water film, while the color change of silver coating is relatively slow due to dry weather in winter.

3. The Influence of Light on The Silver Layer

The silver-plated layer has very active chemical reactivity in the light, and it is easy for silver-plated layer to produce chemical reaction with external sulfides, causing the surface of the silver-plated layer to corrode and accelerate the discoloration. Light is an additional energy source that promotes the ionization of metallic silver. Related studies have shown that the wavelength and time of irradiation. Light is an additional energy source that promotes the ionization of metallic silver. Relevant researches show that the wavelength and time of the irradiation light have a great effect on the discoloration of the silver coating. The shorter the wavelength of the light, the more obvious the discoloration of the silver layer. The light is an intrinsic factor that accelerates the discoloration of the silver plating layer. Therefore, the effect of light on the silver layer during the production process cannot be ignored.