The Basic Composition Of Electroplating Solution

The basic composition of electroplating solution

Main salt deposits metal salts mainly include single salt, such as copper sulfate, nickel sulfate, and so on; Compound salt, such as sodium zincate, sodium cyanozincate, etc. The main function of the complexes formed by the complexes and the deposited metal ions is to change the electrochemical properties of the bath and control the electrode process of the deposition of metal ions. The complexes are an important component of the bath and have a great influence on the quality of the coating. Commonly used complexes are cyanide, hydroxide, pyrophosphate, tartrate, ammonia triacetin acid, citric acid, and so on. The role of conductive salt is to improve the conductivity of the bath, reduce the voltage of the tank end and improve the current density of the process. For example, add Na₂SO₄ to the nickel plating solution. Conductive salts do not participate in the electrode reaction, acids or bases can also be used as conductive substances. Buffering agent in weak acid or alkaline bath, pH value is an important process parameter. The buffering agent is added to make the bath self-adjust pH value so that the pH value can be kept stable during the plating process. Buffer to have enough to effectively control the acid-base balance, generally add 30~40g/L, such as potassium chloride zinc plating solution in boric acid. Anodic activators in the process of electroplating metal ions are constantly consumed, most plating solutions rely on the soluble anode to supplement so that the amount of metal precipitated cathode and anode dissolution is equal, to maintain the balance of plating solution composition. The addition of an active agent can maintain the anode active state, will not occur passivation, and maintain a normal dissolution reaction. For example, Cl- must be added to the nickel plating solution to prevent nickel anode passivation. Special additives In order to improve the performance of the bath and improve the quality of the coating, it is often necessary to add some special additives. The amount added is small, generally only a few grams per liter, but the effect is significant. This kind of additive variety, according to its role can be divided into (1) brightener - which can improve the brightness of the coating. (2) Grain refiner - can change the crystallization condition of the coating, and refine the grain, so that the coating is dense. For example, in zincate galvanized solution, adding additives such as condensation of epichlorohydrin and amines, the coating can be changed from spongy to dense and bright. (3) Leveling agent - can improve the bath micro dispersion ability, making the matrix micro rough surface smooth. (4) Wetting agent - can reduce the interfacial tension between the metal and the solution, so that the coating and the substrate are better attached, and reduce the pinhole. (5) Stress reliever - can reduce the coating stress. (6) Coating hardener - can improve the hardness of the coating. (7) Masking agent - can eliminate the influence of trace impurities.

IKS PVD company, decorative coating machine, tools coating machine, DLC coating machine, optical coating machine, PVD vacuum coating line, the turn-key project is available. Contact us now, E-mail: iks.pvd@foxmail.com