Fastener phosphating treatment is a commonly used metal surface treatment technology, which is designed to improve the rust prevention performance and coating adhesion of metal materials.
Author: Anna
Fastener phosphating treatment is a commonly used metal surface treatment technology, which is designed to improve the rust prevention performance and coating adhesion of metal materials. Phosphating treatment is through a chemical reaction, the formation of a thin film composed of phosphate on the surface of the metal, this film can effectively isolate the metal from contact with oxygen and moisture in the air, thus playing a role in preventing corrosion.
The following is the basic process of fastener phosphating treatment:
Pretreatment:
Cleaning: Use solvent cleaning or alkaline cleaning agents to remove grease, dust and other contaminants from the fastener surface.
Acid washing: Sometimes it is necessary to acid wash to remove the surface of the oxide skin or rust to ensure that the phosphating film can be evenly covered in the metal surface.
Activation treatment:
Activation treatments are usually applied to further clean the metal surface and promote the formation of a phosphate film. Special activators may be used or a short soak before going directly into the phosphate bath.
Phosphating Treatment:
Fasteners are immersed in solutions containing phosphates, usually these solutions also include components such as accelerators (e.g., nickel nitrate), stabilizers, and buffers.
Under appropriate temperature and time conditions, a chemical reaction occurs on the metal surface, forming a thin, uniform phosphate film.
Post-treatment:
Washing: After completing the phosphate treatment, the fasteners need to be thoroughly rinsed with water to remove the residual phosphate solution.
Drying: It can be dried naturally or blown dry with compressed air.
If required, passivation treatment can also be carried out to enhance the corrosion resistance of the phosphate film.
Inspection:
Appearance inspection of the phosphated fasteners to ensure that the phosphating film is uniform and complete, with no spots, leakage of plating or other defects.
It may also be necessary to carry out salt spray test and other tests to verify that its corrosion resistance meets the standard requirements.
Packaging storage:
Qualified fasteners should be properly packaged to avoid damage or contamination during storage and transportation.
Phosphating treatment is applicable to a wide range of metal materials, including steel, zinc alloy, etc. For fasteners, there are different types of iron phosphating, manganese phosphating and zinc phosphating in common, and each type has its specific application scenario. When choosing a phosphating process, you need to determine the most suitable type of phosphating and treatment conditions according to the specific use of fasteners.