1) The main salt
The main salt is the salt in the bath that deposits the required metal on the cathode to provide metal ions. The main salt concentration in the plating bath must be in a proper range. When the other conditions are constant, the main salt concentration increases or decreases, which will affect the electrodeposition process and the final plating organization. For example, the main salt concentration increases, the current efficiency increases, the metal deposition rate increases, the crystal grains of the plating layer become coarser, and the solution dispersion ability decreases. (zinc chloride)
2) Luo mixture
In some cases, if the metal ion of the main salt in the plating solution is a simple ion, the crystal grain of the plating layer becomes coarse. Therefore, a plating liquid of a complex ion is used. The method for obtaining complex ions is to add a complexing agent, that is, a substance capable of complexing the metal ions of the main salt to form a complex. Complexes are "molecular compounds" formed by the interaction of simple compounds. In the bath containing complexes, the main effect of plating is the relative content of the main salt and complexing agent, ie, the free amount of the complexing agent, not the absolute content. (In electroplating under alkaline conditions, since most of the metal ions are precipitated as hydroxides, it is necessary to use electroplating with complexes. At this time, Luohe mixture is an essential component of the bath. Hydroxide in zincate bath Sodium and triethanolamine.)
3) Additional salt
Additional salts are some of the alkali or alkaline earth metal salts other than the main salts in electroplating and are mainly used to increase the electroconductivity of the electroplating bath and do not complex the metal ions in the main salt. Some additional salts can also improve the plating ability of the bath, dispersion, and produce a detailed coating. (The quality of potassium chloride and sodium chloride is not very good)
Buffers are substances used to stabilize the pH of a solution. These substances are generally composed of weak acid and weak acid salt or weak base and weak base salt. When the solution encounters alkali or acid, the pH change of the solution is reduced. (boric acid)
5) Anode activator
The substance that promotes anode activation in the bath is called an anodic activator. The role of the anodic activator is to increase the current density at which the anode begins to passivate, thereby ensuring that the anode is in an activated state and can be normally dissolved. When the content of anode activator is insufficient, the dissolution of the anode is not normal, and the content of the main salt decreases rapidly, which affects the stability of the plating solution. (for cyanide copper plating)
Additives are substances that do not significantly change the electrical conductivity of the coating, but can significantly improve the performance of the coating. According to the role played in the bath, additives can be divided into: brighteners, leveling agents, and anti-fogging agents.
Copyright © Dyshine Industry Co.,Ltd All Rights Reserved.