After electroplating with alkaline galvanized brightener, hydrogen embrittlement is easy to occur in electroplating plants because the hydrogen ions generated on the metal surface are reduced to hydrogen atoms and infiltrated into the metal during the process of electrogalvanizing.
Hydrogen atoms are diffused inside the metal and recombined into hydrogen molecules. At this time, hydrogen molecules can not easily escape from the metal because of their large volume, and form high-pressure "hydrogen bubbles" in the metal microstructure (such as grain boundaries, dislocations, etc.), which will cause local stress concentration, weaken the cohesion of metal materials, resulting in increased brittleness of materials. This makes the metal more likely to break when subjected to external forces.
In order to prevent hydrogen embrittlement after galvanizing, the following precautions are usually taken：
1. Material cleaning: thoroughly clean the surface of the material to remove oil and impurities that may lead to hydrogen generation.
2. Control plating conditions: In the application of alkaline galvanized brightener, we can properly adjust the plating process parameters, such as reducing the current density, adjusting the pH value and controlling the temperature of the plating solution.
3. Post-treatment baking: Low temperature annealing or baking is carried out immediately after electroplating, which helps to let the hydrogen inside the metal escape, thereby reducing or removing hydrogen embrittleness.
4. Control the stress level of the workpiece: reduce the internal stress and residual stress of the workpiece, such as through stress removal treatment or appropriate forming process.
The above are some measures to prevent hydrogen embrittlement after galvanizing, as we all know, in addition to the qualified coating to see whether there is hydrogen embrittlement, but also to see whether the coating crystallization is fine, coating thickness is uniform, in order to improve these two properties, we can use Bigely alkaline alkaline galvanized brightener BZ-515, the obtained coating can meet customer requirements.
If you need alkaline zinc brightener, please feel free to contact us.