On the substrate surface condition of coverage

The surface state of the substrate affect the coverage of the main factors. Practice shows that the metal base material in different electrodeposition, the same bath coverage varies widely. As with chromic acid solution chrome, chromium copper, nickel, brass and steel deposition, in descending order of the bath coverage. This is because when the metal ions in the different Molybdenum tube is deposited on the substrate, it had a great potential difference between the values. Small overpotential deposition potential of more positive, even at the lower part of the current density can reach the value of the deposition potential, so its better coverage. The surface state of the substrate coverage of the complex. In general, the same bath at the substrate surface finish high covering power than its rough surface coverage is good. This is because a high surface finish its true high current density, easy to achieve a metal deposition potential; the rough surface, since a large surface area, the true current density is low, easy to achieve the deposition potential of the metal, and the large amount of hydrogen is precipitated. In addition, if the substrate surface plating pre-treatment is bad, there is no divisible film, various film or dirt into the phase, but also will prevent the deposition of the coating leaving the coverage decreases.
Third, the state of the substrate surface of the binding
Binding usually refers to an object on another object sticks cut the throat scope and extent. If a mechanical force or deformation of the coating due to fall off, or gas stripping or corrosion and peeling, then coating the lack of binding force. Binding is an important performance indicators electrodeposition, it is the base material surface condition before plating has a very direct and significant relationship between the binding and direct impact on the quality of the quality of the coating.
If the surface of the substrate there are a lot of oil, corrosion products and other contaminants, the plating layer is not directly with the substrate surface combined, resulting in the coating gradually from the skin, loss, etc., which is the coating and the substrate surface binding poor sake . In contrast, if prior to plating, electroplating production line the surface of the base material to obtain a good cleaning, the plating layer will be in direct contact to the substrate surface of the molybdenum plating, and with a solid combination. Of course, the metal ion in the metal electrodeposition but also with many other factors, the surface state of the substrate is not the only factor affecting the binding force, but it is the most important factor affecting binding.