Lock knowledge: stainless steel crescent lock pretreatment content and use
We all know that the Crescent Lock will do some pre-treatment work before leaving the factory. These are all important to ensure the quality and performance of the surface treatment.
Generally, the stainless steel material of the crescent lock is in the production practice, and there are many quality accidents of the electroplated parts. It is not the electroplating process itself, but is caused by improper pretreatment and poor pre-plating. In general, the pre-treatment applications for electroplating that we most often contact include the following:
1, improve the electrode reaction
The electroplating process must be carried out in the condition that the electrolyte is in good contact with the surface to be coated of the workpiece and the workpiece is wetted by the plating solution. Contaminants such as oil stains, rust layers, and scales on the surface of the workpiece prevent the electrolyte from coming into full contact with the metal substrate, making the electrode reaction difficult and even impossible to occur due to isolation. If the dirt is not clean, such as a part of the oil or oxide remains, the coating will not be dense, porous, or even discontinuous; or the coating will be prone to small bubbles or even "blood" when heated.
2, to ensure better bonding
The plating epitaxially grown on the base metal lattice has a good bonding force. It is obvious that epitaxial growth requires the exposure of the base metal lattice, and any oil stain, rust, including a very thin oxide film, will affect this electrocrystallization process. The metal bond force and the molecular force between the plating layer and the substrate are short-range forces, and the surface of the substrate must be clean and smooth. When a very thin or even invisible oil film or oxide film is adhered to the plating member, although a coating having a normal appearance and fine crystal appearance can be obtained, the bonding strength is greatly lowered, and the workpiece is subjected to bending, impact or cold heat, and the plating layer is formed. It will crack or fall off, which is a hidden danger that is easily overlooked.
3, to ensure that the plating is smooth and smooth
The stainless steel crescent lock has a rough surface and the coating is rough and uneven, which is difficult to flatten after plating. Rough and uneven coatings not only have poor appearance, but also have a corrosion-resistant coating that is not as smooth and smooth. Cracks on the workpiece, cracks, dirt at the blisters are difficult to remove, and acid and alkali and electrolyte are accumulated. The plated parts ooze out of the corrosive liquid layer during storage, causing "black spots" or "white spots" on the plating. , greatly reducing the corrosion resistance of the coating.
Summary: In general, the pretreatment of stainless steel crescent locks reflects the rigor of different manufacturers to a certain extent. Therefore, consumers should consider the surface of the crescent lock when choosing the crescent lock. These are justifiable.