Normal temperature barium salt modified phosphorizing liquid capable of avoiding water wash after phosphorized

Abstract

The invention relates to a phosphating washing-free phosphating solution modified with barium salt at ambient temperature. The phosphating solution comprises a phosphoric acid, a nitric acid, and Zn2+, Ca2+, Mn2+, Ni2 plus salt thereof, ammonium molybdate,ammonium tungstate, phytate, H2O2 and barium nitrate or barium hydroxide. The pH value ranges from 1.6 to 4.2. The invention can be phosphated under soak, rinse, brush or the combined way thereof at 3 DEG C.to 45 DEG C.. The phosphating solution is stable and capable of automatically precipating and removing the SO42- inside the phosphating solution and therefore eliminating the influence of SO42- on quality; the phosphorizating membrane is continues, uniform and compact, the membrane weight is between 0.5g is multiplied by m and 3.0g is multiplied by m minus 2 and the iron-red epoxy primer is sprayed and the adhesion thereof can be 1 grade.

Description

technical field [0001] The invention belongs to the technical field of iron and steel surface phosphating treatment, and relates to a normal-temperature barium salt modified phosphating solution that can be washed without water after phosphating. Background technique [0002] Phosphating treatment, with a history of more than 100 years, is a process in which metal workpieces are treated in a solution composed of metal or ammonium dihydrogen phosphate, oxidant, and film-forming aids, and a phosphating film is formed on the surface of the treated metal. The phosphating film as the bottom layer of the coating can significantly increase the adhesion, protection ability and other properties of the coating. [0003] Phosphating, when the steel surface contacts the phosphating solution, the following reactions occur ([O] represents the oxidizing agent and dissolved oxygen in the phosphating solution): [0004] Fe+[O]+H 2 O → Fe 2+ +2OH - [0005] 2Fe 2+ +[O]+H 2 O→2Fe 3+ +2...

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Problems solved by technology

At present, the phosphating solution used for spraying pretreatment generally needs to be washed with water after phosphating, otherwise the film-forming reaction in the phosphating solution, degreasing and rust removal, and SO 4 2- , Cl - 、Na + And certain additives (such as fluorine-containing compounds) in the phosphating solution will cause unacceptable defects in the quality of the phosphating film (film rust, looseness, serious ash), and washing with water will change the phosphating solution, which accounts for more than 20% of the total consumption. become pollutants to be treated, waste materials, pollute the environment, and increase costs; ② Sulfate ions (SO 4 2- ), chloride ion (Cl - ) and the phosphating solution components and film-forming reaction by-products accumulate to cause the short life of the phosphating solution; ③ the phosphating temperature is basically above 15°C, and generally needs to be heated in winter; ④ normal temperature phosphating solution accelerators generally contain toxic Ni ( Nickel) and Cr (chromium) and decomposition to produce toxic gas nitrogen oxides (NO X ), carcinogenic nitrite, poor phosphating quality, etc.; 2 Produce several grams or more of sediment

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