Application scope of gold plating: Gold plating has two types: for similar materials and for dissimilar materials. The former refers to the gold plating performed for gold jewelry surfaces, so as to improve brightness and lustre. The latter refers to the gold plating performed for non-gold material surfaces, such as silver and copper, so as to replace the base material’s lustre with gold’s lustre for improved visual effects. The gold plated coating is golden yellow and has very high chemical stability which makes it dissolved only in aqua regia and other super acids. There are univalent gold and trivalent gold. The former’s standard potential φ°Au+/Au is +1.68V, and the latter’s standard potential φ°Au3+/Au is +1.50V. For steel, copper, silver and their alloys as the substrate, the gold plated coating is negative whose pores affect its protective property. The gold plated coating has good ductility, polishability, high temperature resistance and excellent discoloration resistance. Performing gold plating for silver can prevent it from changing color. Performing gold plating for gold alloys can present multiple hues, so it is often used for decoration, covering jewelry, clock and water parts, and artworks. Featuring low contact resistance, good conductivity, good weldability, high corrosion resistance, and a certain abrasive resistance (for hard gold), gold plated coatings are widely used in various fields including precision instruments and apparatuses, printed circuit boards, integrated circuits, pipe shells, and electric contacts
Why does the CNC turning connector need gold plating? The connector is an important electrically conductive part used in household appliances. Its conductive contact mode is inserting the pin into its countersunk head through hole, and the pin is composed of a spring and a pin tube. For the whole product, besides the connector, pin, pin tube and spring processes, its electroplating is also important. Electroplating can directly leads to a good or bad finished product and determines whether a product is qualified or scrapped. Without gold plating, neither the connector or the spring does not bear large currents, and the pin does not have so stable signals or electrical conductivity.
The spring is made of beryllium copper, stainless steel, and music wire. Various materials have their own unique features, and some basic considerations like operating temperature, impedance and elastic force requirements are needed in the spring design field. Silver plating is basically performed for springs, but gold plating is required for better electrical conductivity, because gold helps improve electrical coductivity and high thermal properties in a better way and features oxidation and corrosion resistance.
The pin tube is also a CNC turning part which usually goes through both nickel plating and gold plating during electroplating. Nickel plating is performed first for a base coating of nickel which is normally 1-2 μm thick (40u”=1 μm), and gold plating is for a common surface treatment coating which is basically 0.1~1.0 μm thick. For a blind hole pipe which is long and has a small diameter, it is a challenge to electroplate its inner wall. Normally, we drill a side hole at the lower end, allowing the electroplating liquid to fully form a backflow at the pipe bottom, so as to ensure that some gold deposits on both the inner wall and the pipe bottom. Or we will inform the customer of the designed basic proportion: length and inner diameter of the pipe.
The pin shaft is basically gold plated. Gold plating is the preferred treatment, because gold has good electrical conductivity and oxidation resistance. In addition, the thickness of the gold plated coating absolutely affects the whole product’s service life. We choose the nickel base treatment and determine the thickness of the gold plated coating out of the consideration of costs. Other gold electroplating solutions with rhodium, palladium and some noble metals are also used for different requirements of different products.
Brass is applicable to a lot of industries besides the electrical appliances. Yijin Hardware is quite experienced in manufacturing precision custom CNC turning brass parts. If you want a custom precision CNC turning brass part, contact Yijin Hardware!