Electroplating solution knowledge that affects plating quality
The primary salt refers to a salt in the plating solution that is capable of depositing the desired plating metal on the cathode to provide metal ions. The concentration of the main salt in the bath must be within an appropriate range, and the concentration of the main salt is increased or decreased. When other conditions are constant, the electrodeposition process and the final coating structure are affected. For example, the concentration of the main salt increases, the current efficiency increases, the metal deposition rate increases, the coating particles are coarser, and the solution dispersibility is lowered.
In some cases, if the metal ion of the main salt in the plating solution is a simple ion, the crystal grains of the plating layer are rough, and therefore, a plating solution of a composite ion is used. The method of obtaining the composite ion is to add a complexing agent, that is, a substance capable of complexing the metal ion of the main salt to form a complex. A complex is a "molecular compound" formed by the interaction of simple compounds. In the plating solution containing the complex, the main effect of the plating effect is the relative content of the main salt and the complexing agent, that is, the free amount of the complexing agent, rather than the absolute content.
Additives are substances that do not significantly alter the conductivity of the coating and can significantly improve the performance of the coating. According to the role of the plating solution, the additive can be classified into a whitening agent, a leveling agent and an antifogging agent.
Buffer refers to a substance used to stabilize the pH of a solution. These materials typically consist of weak acids and weak acid salts or weak bases and weak base salts which lower the pH of the solution when the solution is exposed to a base or acid.
The substance that promotes the activation of the anode in the plating solution is called an anode 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 for normal dissolution. When the content of the anode activator is insufficient, the anode is abnormally dissolved, and the content of the main salt is rapidly decreased, which affects the stability of the plating solution. In severe cases, plating does not work properly.
Factors affecting plating quality
PH value, additive, current density, current waveform, temperature, stirring speed, etc.
Electroplating can be electroplated with different metals, galvanized, nickel plated, chrome plated, etc.