Aluminium-alloy chromium-free in-situ phosphating liquid and preparation method thereof

Abstract

The invention discloses an aluminium-alloy chromium-free in-situ phosphating liquid and a preparation method thereof. The luminium-alloy chromium-free in-situ phosphating liquid comprises the compositions in percent by mass: 1-5% of phenylphosphonic acid, 0.1-0.3% by tartaric acid, 0.1-0.3% of citric acid, and the balance an organic wetting dispersant and organic paint. Phenylphosphonic acid is taken as the main composition of an in-situ phosphating agent, tartaric acid and citric acid are taken as organic additives, and the phosphating liquid does not contain nitrites, does not contain nickel ion and chromium ion, and is free of pollution to environment. Phenylphosphonic acid and the organic paint form a stable uniformly-mixed film-forming substance, and an organic coating is formed on the surface of an aluminium alloy base body, so that metal phosphating processing and coating of the organic coating are combined, multiple coating operations are simultaneously finished in one process, and the economic cost of the multi-step coating technology and the operation complexity are effectively reduced. Operations of phosphating processing and chromate sealing are reduced, time, energy, resource and labor force are saved, discharge of toxic substances is reduced, and the preparation method is a green clean technology. Additionally, the preparation method is simple, convenient to operate and use, and free of technological difficulty.

Description

technical field [0001] The invention belongs to the technical field of aluminum alloy surface treatment and is mainly used for surface treatment of aluminum alloy profiles before coating. Background technique [0002] The traditional metal coating process is a multi-step process. It has to go through multiple processes such as degreasing, rust removal, phosphating film formation, sealing, drying, etc., and then apply organic coatings, metal phosphating film formation and organic coating. The formation of layers is separated separately, the process is complicated, the process parameters are many, and the operation control is difficult. In addition, after the metal has been phosphating, there are still 1% to 5% of the small pores on the surface, which leads to the unsatisfactory corrosion resistance of the metal coated with organic coatings. The toxic solutions, heavy metals and other toxic Substances are extremely polluting to the environment. Now the global calls for envir...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the defects such as the unsatisfactory anti-corrosion performance and complex operation process (phosphating and coating organic coating carried out step by step) in the traditional phosphating film / organic coating coating process, and can simplify the metal coating process. Coating process, reduce production cost, provide a chromium-free aluminum alloy in-situ phosphating solution and its preparation method, which can meet the requirements of environmental protection and clean production

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