The uniformity and integrity of the coating on the surface of the cathode is an important factor that determines the quality of the coating. It affects the protective performance of the coating to a certain extent. Dispersibility and coverage are commonly used in electroplating to assess the uniformity and integrity of the metal coating on the cathode.
The dispersibility of the plating solution (denoted by T•P) refers to the ability of a certain solution to make the electrode (usually the cathode) plating distribution more uniform than the primary current distribution under certain conditions. From this it can be seen that the dispersive power is of a comparative nature and the basis of its comparison is the primary current distribution. The so-called primary current distribution is the cathodic current distribution considering only the different cathode surface to anode geometrical distances. The higher the ability of the coating to be evenly distributed over the part, the better the dispersion of the plating solution. What is involved here is the distribution of the coating on the macroscopic profile. The concept of leveling capability can be used for the distribution of the microscopic surface coating. The so-called leveling capability (ie, microscopic dispersion capability) refers to the ability of the bath to form a plating layer on the bottom layer that enables the microscopic profile of the plating layer to be smoother than the bottom layer (indicated by M•T•P). It expresses the uniformity of the distribution of the coating on the surface where the roughness of the bottom layer is relatively small, the depth of the wave hole is less than 0.5 mm, and the distance between the wave crest and the wave trough is small. This property is very important for obtaining high quality bright decorative plating. The coating ability of the plating bath refers to the ability of the bath to deposit metal plating in the grooves or deep holes under specific conditions (indicated by C•P). It refers to the completeness of the distribution of the plating on the part. The higher the coverage, the deeper the plating. Poor coverage, metal plating can not be plated in the concave parts.
The dispersive power of the bath differs from that of the coverage. Pay attention to the difference and do not mix it. When quantitatively expressing the values of dispersion capacity and coverage ability, it is necessary to specify the measurement method. The measurement results of different methods are difficult to compare.