6 post-plating treatment technologies that can not be ignored in electroplating process
| The purpose of electroplating post-treatment is to ensure the quality of the coating and improve the protective, decorative and functional properties of the coating. Post-plating treatment is very important, but it is often overlooked. In actual production, it often breaks down, and even the previous work has been exhausted. Therefore, relevant personnel should pay attention to it.
The post-plating treatment process is selected according to the performance of the electroplated layer, use requirements, environmental impact and other factors, usually including polishing, passivation, coloring, coating, sealing, and hydrogen removal.
Common post-plating treatment:
Polishing is a process of improving the surface flatness and reducing surface roughness of metal workpieces through chemical polishing or mechanical polishing. It can be directly used for metal surface processing, as well as for pre-plating and post-plating metal workpieces. finishing. Such as copper, nickel and other alloys and the decorative finishing of metal plating layers such as copper, nickel, and chromium after plating.
The so-called passivation treatment refers to a metal surface treatment method in which a chemical treatment is carried out in a certain solution to form a solid, dense, and highly stable thin film on the coating. Passivation greatly improves the corrosion resistance of the coating and can increase the surface gloss and anti-pollution ability. This method is very versatile. After zinc plating, copper, etc., passivation can be performed.
Hydrogen removal treatment
Most metal substrates, such as steel and copper, will produce “hydrogen” during pretreatment (pickling, cathode electrolysis) and electrodeposition. Some of them have not had time to form “hydrogen”, that is, “hydrogen atom”. The form of “infiltrates into the substrate and the coating, causing brittleness of the plated parts, and severely reducing the tensile strength of the parts, which is called hydrogen embrittlement. Therefore, parts used in aerospace, automobile manufacturing and other fields must undergo “dehydrogenation” treatment after plating, and some parts that require high tensile strength during use must also undergo “dehydrogenation” treatment. The hydrogen removal treatment is carried out at a temperature of about 200°C, and the treatment time is determined according to the required tensile strength of the part. The hydrogen removal treatment should be carried out within 3 hours after plating.
Metal surface coloring is the use of chemical, electrochemical, replacement or heat treatment methods in a specific solution to form a film of different colors or interference film on the metal surface. Due to the different colors of various metal oxides, the colored metal surface presents different colors, which changes the appearance of the original metal and achieves the purpose of imitating expensive metals, antiques, and decorations.
Coating is the process of coating or dipping a transparent organic film on the parts with silver and imitation gold plating to prevent or continue the discoloration of the plating.
In order to improve the corrosion resistance of the workpiece in the atmosphere, physical, chemical or electrochemical methods are used to make the surface (or intermediate coating) evenly covered with a layer of film. This process is called sealing.
Pre-treatment plays a key role in the effect of electroplating, and post-treatment has a significant promotion effect on the performance of electroplated parts. In order to ensure the performance of electroplated parts, a reasonable post-plating process is necessary.