The importance of pre-plating

Plating pre-treatment in the electroplating plating production line is a very crucial step, the substrate surface treatment directly affects the quality of coating, hence, considerable attention before plating process. This article describes the surface state of the various factors that affect the quality of the coating, electroplating production line expounded before plating processing of basic methods.Before plating plating plating process is to determine the quality of one of the most important factors. In actual production, electroplating failure rate more than 80% of the pretreatment step, so the effect is good or bad before plating treatment is particularly important, following detailed description of the surface state of the substrate on the coating structure and binding force of impact.First, the state of the substrate surface structure of the coatingThe coating is composed of crystals or grains, the crystal size, shape and arrangement of the structural characteristics of the coating determines. In a variety of plating solution, the metal coating is different structural characteristics, Molybdenum tube due to a difference deposition process. Plating begins when the first surface of the substrate to generate a small number of fine points, or crystal nuclei, as time increases, the increase in the number of single crystal and connected to each other into a film, forming a plating layer.
Crystal nucleation and growth process, due to the characteristics of the matrix metal and the different operating conditions and different, there are the following several ways. If electroplating begins, the generated crystal nuclei are many, and all continue to grow, the formation of whiskers and arranged vertically on the cathode surface; if only part of the formation of nuclei grow, there will be the following two situations: crystal nuclei showed a single long needle (dendritic) forms develop in the direction toward the anode and the crystal nuclei in three directions evenly grown, due to the crystal nuclei grow at different speeds, large crystal nuclei will be squeezed out of the small crystal nuclei to form more a conical shape to the more coarse crystals.
If the deposition of crystals generated starting soon stopped growing, and in the surface of these crystals to generate new crystal again, then this case, the position of the resulting crystals will be confused with, the coating obtained is cyanide electrolyte which kinds of situations. In addition to being electrolyte composition coating structure, the impact of process conditions, but also by the surface condition of the substrate seriously affected. If the surface of the substrate a mechanical impurities harmful to the coating tissue; but for the electrolyte or the adhesion of the coating on the substrate, will form Ma Hang; if adhesion on the electrolyte, will form nodulation. These impurities caught in the coating, but also reduce the ability of anti-rust coating. If the substrate surface with oil, oxide, etc., it is impossible to obtain a coating with a solid; rough surface of the substrate, the coating is difficult to obtain bright; sometimes substrate coating will produce tissue and tissue reproduction, was crystalline pattern . Therefore, selecting the appropriate surface of the substrate pre-treatment process, the quality of the plating layer has a very important significance.