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Surfactants used in metal processing
Release Date:2016-9-6 Source:xiashundong Views:923
Metalworking include metal cleaning, surface finishing and metal turning, milling, planing, cobalt, rolling and casting process. In order to reduce labor intensity, improve product quality, save energy, reduce costs, to be used in various machining processes often Some additives, wherein the surfactant plays an important role.

1、 surfactants and performance
Refers to a surfactant can significantly reduce the surface tension of the liquid or liquid-liquid interfacial tension materials they are made of polar molecules of the hydrophilic group and non-polar hydrophobic group composed of two parts. The hydrophilic group is a carboxyl group common , sulfate, sulfonate, amine, quaternary amine or hydroxy;. hydrophobic group is a long-chain alkanes and aromatics as the representative of a group since they have both hydrophilic and lipophilic "amphiphilic" in nature, chemical cleaning can thus cleaning solution surface (or interface) properties change, it has a low surface tension. Depending on the electric charge of the surface-active portion of the surfactant into anionic, cationic, nonionic and amphoteric surface active agent having a wetting, foaming, solubilization, foaming properties.

2、 of surfactants in Metal Processing
2.1 Application of metal cleaning
Metal cleaning Metal fact throughout the entire process. The main cleaning agent from the main cleaning agents, corrosion inhibitors, surfactants constitutes three components. Surfactants in Chemical Cleaning plays adsorption, penetration, emulsification, dissolution, washing effect, the chemical cleaning agents not only as an auxiliary, but also as a main component obtained widespread attention, especially in acid, caustic, corrosion, oil, killing and other cleaning process has played an increasingly big role. At present, the surfactant is a water-based cleaning body overcome the lack of chemical pickling, caustic chemical cleaning agents and other several, become the main development direction of the metal cleaning.
Water-based metal cleaner advantages: high cleaning efficiency, to pollution and strong; safety performance is good, do not pollute the environment; energy conservation, low-cost washing; washing process for washing parts is no damage, no corrosion and other parts of washed .
Water-based cleaning agent and more non-ionic surfactant and anionic surfactant compound as the main material, together with a mixture of adjuvants composed of the former to the sewage capacity, has a good anti-rust, corrosion inhibition, the latter can progress and improve the overall performance of the cleaning agents. its cleansing mechanism by means of a surfactant wetting, penetration, emulsification, solubilization, dispersion and so on, so that the adhesion to the metal surface of the oil to weaken, and then subjected to mechanical stirring, scrub, heating, ultrasound and other physical methods, so that the oil from the metal surface, and enter the wash liquor is emulsified dispersed.
Metal cleaning commonly used surfactants are polyethylene oxide ethers of fatty alcohols, alkyl phenol ethylene oxide ether, sodium dodecylbenzenesulfonate, sodium dodecyl glycol amides, fatty acid amide methoxy benzene sulfonate.
Wang Yu and other studies of double-octyl ether and polyoxyethylene dialkybenzene disulfonates categories Gemini surfactant-based metal cleaning agent performance. The results show that contains anionic / nonionic surfactant Gemini metal cleaning fluid has a high surface activity, there is a good synergy between the anionic / nonionic Gemini surfactants.

2.2 Application of metal phosphate treatment
Phosphate treatment is treated with a dilute solution of a metal containing phosphoric acid, phosphate and other chemicals. Metal surface in the solution with phosphoric acid, phosphate chemical reaction medium, into a complete insoluble metal phosphates having a medium resistant to corrosion the layer of this metal phosphate conversion coatings on a variety of applications, it can improve the paint and metal combining power and corrosion resistance; also be used as carriers of anti-rust oil, a lubricant during cold metal carrier and friction lubricant table.
To improve the phosphate film structure, improve the effect of phosphate, phosphate solution also contains other additives, including the role of the surfactant include: metal surface adhesion of the oil emulsion having a solubilizing effect, and can prevent re-precipitation of dirt ; the solution was to produce wetting, penetration, is conducive to the contact surface with the metal phosphate solution; reduce the surface tension of the liquid, the reaction of hydrogen phosphide in favor of escape, to strengthen the cathodic polarization, thus accelerating the phosphate film forming process.
Phosphating conventional surfactants are condensates of ethylene oxide and from various hydrophobic long-chain hydrocarbons, i.e., non-ionic surfactants.

2.3 Application of metal plating
In the electroplating process, in order to improve the electrolyte performance and improve the quality of the coating is often necessary to add some additives, wherein the surfactant is one of the main varieties, it has a smooth, bright, diffusion, change the physical properties of the coating, suppressing acid mist Yi a role.
Electroplating commonly used surfactants are peregal, OP emulsifier, sodium lauryl sulfate, methylene-bis-naphthalene sulfonate, a fluorine surfactant, a fatty acid ester of polyethylene oxide, polyethylene oxide castor sesame oil and the like.

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