What are the applications of anionic fluorocarbon surfactants in the field of metal processing
Anionic fluorocarbon surfactants have wide and critical applications in the field of metal treatment due to their unique properties such as high surface activity, chemical resistance, and thermal stability. The following elaborates on multiple process steps:
1、 Metal cleaning and degreasing
Efficient removal of oil stains and impurities: Anionic fluorocarbon surfactants can significantly reduce the surface tension of water (which can be reduced to below 20 mN/m). Pollutants such as oil stains and wax that penetrate the metal surface can be separated from the metal substrate through emulsification and dispersion. For example, in the degreasing and cleaning of automotive parts and aerospace metal components, mineral oil, animal and vegetable oils, and cutting fluid residues can be quickly removed, and the cleaning efficiency is increased by more than 30% compared to traditional surfactants.
Resistant to strong acid/strong alkali environment: It remains stable in strong alkaline cleaning solutions (such as sodium hydroxide concentration ≥ 10%) or acidic systems (such as hydrochloric acid, sulfuric acid media), suitable for strong alkali degreasing tanks before electroplating or rinsing processes after acid rust removal. In the two-step cleaning process of "alkali washing acid washing" for steel parts, adding fluorocarbon surfactants can enhance the wetting properties of the cleaning solution and avoid poor adhesion of the subsequent coating due to poor cleaning of the metal surface.
2、 Metal Electroplating and Coating
1. Improve the performance of electroplating solution:
In electroplating processes such as chrome plating and zinc plating, anionic fluorocarbon surfactants can be used as wetting agents to reduce bubbles in the plating solution and avoid defects such as pinholes and pitting in the coating. For example, adding a small amount of fluorocarbon surfactant to decorative chrome plating solution can make the chromium coating more uniform and shiny, and increase the light reflectivity by 15% -20%.
When chemically plating nickel phosphorus alloy, its dispersibility can promote the uniform deposition of metal ions and improve the consistency of coating thickness, especially suitable for surface treatment of complex geometric parts such as pipes and cavities.
2. Improve coating adhesion and corrosion resistance:
As a coating additive, adding it to metal anti-corrosion coatings (such as epoxy zinc rich primer, polyurethane topcoat) can reduce the surface tension of the coating, make it spread more evenly on the metal surface, and reduce sagging and shrinkage phenomena. For example, in steel structure coatings for marine engineering, fluorocarbon surfactants can enhance the adhesion between the coating and the metal surface. After salt spray testing (5000 hours), the coating did not peel off and the rust area was ≤ 0.5%.
In metal anodizing treatment, the addition of fluorocarbon surfactants can adjust the surface tension of the electrolyte, promote the uniform growth of the oxide film, improve the density and weather resistance of the oxide film (such as extending the UV aging resistance time of aluminum alloy anodizing to over 2000 hours).
3、 Metal cutting and forming
1. High performance cutting fluid additives:
In the process of metal cutting (turning, milling, drilling), anionic fluorocarbon surfactants can be used as emulsifiers or lubricants to prepare water-based cutting fluids. Its high lubricity can reduce the friction coefficient between the tool and the metal workpiece (by 20% -30%), reduce tool wear, and extend tool life (such as increasing the cutting life of hard alloy tools by 50%). At the same time, its excellent heat dissipation can quickly remove cutting heat and avoid deformation of the workpiece due to high temperature.
Outstanding extreme pressure resistance, it can form a high-pressure lubricating film on the metal surface during high load cutting (such as stainless steel and titanium alloy processing), prevent tool and workpiece adhesion, and improve machining accuracy (dimensional tolerance controlled within ± 0.01 mm).
2. Metal forming release agent:
In metal stamping, forging and other forming processes, as a key component of release agent, it can form a low surface energy isolation layer between the metal mold and the workpiece, reducing the release force by more than 40% and avoiding surface scratches or deformations of the workpiece. For example, when hot forging aluminum alloy wheels, the release agent containing fluorocarbon surfactants can be reused more than 500 times, and the surface smoothness of the wheel hub after demolding reaches Ra 0.8 μ m.
4、 Metal anti-corrosion treatment
1. Passivation and phosphating treatment increase efficiency:
Adding anionic fluorocarbon surfactants to metal passivation solutions (such as chromate passivation and chromium free passivation) can enhance the wetting properties of the passivation solution on the metal surface, promote uniform deposition of the passivation film, and improve the corrosion resistance of the passivation film. For example, after chromium free passivation of zinc alloys, the corrosion resistance time of neutral salt spray testing (NSS) has been increased from 72 hours in traditional processes to over 200 hours.
In the phosphating treatment of steel parts, the surface tension of the phosphating solution can be adjusted to promote the refinement and densification of the phosphating film grains, improve the uniformity of the phosphating film thickness (deviation ≤ 5%), and enhance the adhesion between the coating and the metal when used as the bottom layer of the coating.
2. Synergistic effect of gas-phase corrosion inhibitors (VCI):
Combined with amine gas phase corrosion inhibitors, it is used for sealing and packaging of metal products (such as steel plates and precision parts). Anionic fluorocarbon surfactants can reduce the spreading resistance of the corrosion inhibitor on the metal surface, allowing it to adsorb more evenly on the metal surface, forming a hydrophobic protective film, and preventing the erosion of humid and corrosive gases. Experiments have shown that adding fluorocarbon surfactants to VCI packaging films can prevent metals from rusting after being stored in humid environments (humidity ≥ 90%) for 12 months.
5、 Other metal processing techniques
Metal polishing and grinding: used as a dispersant and lubricant in polishing solutions (such as alumina polishing and electrolytic polishing) to prevent abrasive agglomeration, improve polishing efficiency, reduce metal surface scratches, and achieve mirror level polishing effect (surface roughness Ra ≤ 0.1 μ m).
Metal printing and etching: Adding fluorocarbon surfactants to metal plate printing ink can improve the leveling and adhesion of the ink on the metal surface, avoiding blurry printing patterns; In metal etching solution, the uniformity of etching rate can be adjusted to improve the etching accuracy of micro circuits (line width ≤ 50 μ m).