Phosphorus-free conversion (spray) - Aluminum

Phosphorus-free conversion (spraying) of aluminum is a new type of aluminum surface treatment technology. The following is its introduction:

Process

Pretreatment: usually includes degreasing, alkaline washing, matte treatment and other processes to remove oil, scale and other impurities on the aluminum surface, so that the aluminum surface can reach a clean and activated state, ready for subsequent phosphorus-free conversion treatment.

Phosphorus-free conversion spray treatment: The prepared phosphorus-free conversion liquid is evenly sprayed on the pre-treated aluminum surface through a spray device. Under normal temperature or specific temperature conditions, the conversion liquid reacts chemically with the aluminum surface to form a phosphorus-free conversion film. For example, zirconium oxide treatment is carried out at room temperature and the treatment time is short, generally less than 15 seconds.

Post-treatment: After the conversion treatment is completed, it is usually necessary to wash with water to remove the conversion liquid and impurities remaining on the surface, and then dry it so that the conversion film is firmly attached to the aluminum surface. If there are subsequent process requirements such as painting, the dried aluminum parts can directly enter the painting process.

advantage

Good environmental performance: Phosphorus-free conversion treatment avoids the use of phosphorus-containing compounds, reduces phosphorus pollution to the environment, and does not contain harmful substances such as heavy metals, which meets environmental protection requirements. Waste liquid treatment is relatively simple, reducing wastewater treatment costs.

Simple process: Compared with the traditional phosphating process, the phosphorus-free conversion process does not require surface conditioning, nitrite accelerators, etc. The process is relatively simple, which can reduce equipment investment and production site requirements. Some phosphorus-free conversion treatments can be carried out at room temperature without heating, saving energy consumption.

Excellent performance: The formed phosphorus-free conversion film has a strong bond with the aluminum substrate, has good corrosion resistance, wear resistance and coating bonding, can improve the service life and decorative performance of aluminum products, and can partially replace the phosphating film. Its anti-corrosion performance is equivalent to that of the phosphating film and chromate conversion film.

Wide range of applications: One treatment liquid can treat multiple materials such as iron and aluminum at the same time, without the need to replace the tank liquid. It has good adaptability to metal mixed production lines of different materials, reducing production costs.