Views: 0 Author: Site Editor Publish Time: 2026-06-09 Origin: Site
Surfactants are substances that can significantly reduce the surface tension of liquids or the interfacial tension between two immiscible liquids. Their molecular structure consists of two parts: a polar hydrophilic group and a non-polar hydrophobic group. Common hydrophilic groups include carboxyl, sulfate, sulfonic acid, amine, quaternary ammonium and hydroxyl groups, while hydrophobic groups are mainly long-chain alkanes and aromatic hydrocarbon groups.
Thanks to their amphipathic property of being both water-soluble and oil-soluble, surfactants can alter the surface or interfacial properties of cleaning solutions and lower surface tension effectively. Based on the charge carried by their active components, surfactants are classified into four categories: anionic, cationic, non-ionic and amphoteric surfactants. They feature excellent properties such as wetting, foaming, solubilization and defoaming.
Metal cleaning runs through the entire metal processing workflow. Typical metal cleaning agents are mainly composed of three core components: main cleaning agents, corrosion inhibitors and surfactants.
Surfactants perform multiple functions including adsorption, penetration, emulsification, solubilization and detergency in chemical cleaning. They are no longer merely auxiliary ingredients but have become key components, playing an increasingly important role in pickling, alkaline cleaning, corrosion inhibition, degreasing and sterilization. Water-based cleaning agents dominated by surfactants have overcome the drawbacks of traditional pickling and alkaline cleaning products, and have become the mainstream development trend for metal cleaning.
High cleaning efficiency and strong detergency
Excellent safety and eco-friendliness with no environmental pollution
Energy-saving and cost-effective for daily use
Cause no damage or corrosion to metal workpieces during and after cleaning
Most water-based cleaners are formulated with compound mixtures of non-ionic and anionic surfactants together with various additives. Non-ionic surfactants deliver outstanding detergency, rust prevention and corrosion resistance, while anionic surfactants optimize the overall performance of the cleaning formula.
The cleaning mechanism relies on the wetting, penetration, emulsification, solubilization and dispersion effects of surfactants, which weaken the adhesion of oil stains on metal surfaces. Combined with physical methods such as mechanical stirring, scrubbing, heating and ultrasonic treatment, oil contaminants are separated from metal surfaces, then emulsified and dispersed in the cleaning solution.
Commonly used surfactants for metal cleaning include fatty alcohol polyoxyethylene ether, alkylphenol ethoxylate, sodium dodecylbenzene sulfonate, dodecyl diol amide and methoxy fatty amide benzene sulfonate.
Phosphating is a surface treatment process that uses dilute solutions containing phosphoric acid, phosphates and other chemical additives to treat metal workpieces. Through chemical reactions between the metal substrate and the phosphating solution, a dense, insoluble metal phosphate conversion film with moderate anti-corrosion performance is formed on the metal surface.
This phosphate film boasts versatile functions: it enhances the adhesion and anti-corrosion performance of coatings on metals, acts as a carrier for anti-rust oil and lubricants during cold working, and also serves as a lubricant for friction surfaces.
Surfactants are essential additives in phosphating solutions to optimize the structure of phosphating films and improve treatment results. Their main functions are as follows: emulsify and solubilize residual oil on metal surfaces and prevent redeposition of dirt; improve the wetting and penetration capacity of the solution to ensure full contact between phosphating liquid and metal surfaces; reduce liquid surface tension to accelerate the escape of hydrogen generated during phosphating reactions, strengthen cathodic depolarization and speed up film formation.
Non-ionic surfactants synthesized by the condensation reaction of ethylene oxide and various long-chain hydrophobic hydrocarbons are the most widely used products in phosphating treatment.
Various additives are widely used in electroplating to improve the performance of electroplating solutions and the quality of metal coatings, among which surfactants are one of the most important additives. They can realize functions such as coating leveling, brightening, diffusion regulation, modification of coating physical properties and suppression of acid mist volatilization.
Common surfactants applied in electroplating include Peregal, OP emulsifier, sodium dodecyl sulfate, methylene dinaphthalene sulfonate, fluorosurfactants, fatty acid polyoxyethylene ester and polyoxyethylene castor oil.
