CN104342684A - Magnesium alloy work-piece surface anti-corrosion conversion film treatment liquid preparation process - Google Patents

Abstract

The present invention discloses a magnesium alloy work-piece surface anti-corrosion conversion film treatment liquid preparation process, which comprises: 1) taking a right amount of water, adding 30-34 ml/L of 85% phosphoric acid, uniformly stirring, sequentially adding 34-36 g/L of sodium dihydrogen phosphate, 42-46 g/L of calcium nitrate, 12-14 g/L of barium carbonate, 10-12 g/L of sodium fluoride, and 7-9 g/L of zinc nitrate, and stirring for 10-14 min; 2) taking 220-240 ml/L of the measured ethanol, sequentially adding 14-16 ml/L of phytic acid, 18-20 g/L of sodium citrate, 6-8 g/L of potassium sodium tartrate, 4-6 g/L of sodium acetate, 3-5 g/L of ammonium metavanadate, and 5-7 g/L of potassium fluorosilicate, and stirring for 20-30 min; and 3) adding the solution in the step 2) to the solution in the step 1), adding the balance of water, stirring for 30-40 min, and standing for 18-24 h.

Description

The anti-corrosion conversion coating treating fluid blending process of a kind of magnesium alloy work-piece surface

Technical field

The present invention relates to technical field of surface, particularly relate to the anti-corrosion conversion coating treating fluid blending process of a kind of magnesium alloy work-piece surface.

Background technology

Magnesium is one of element that in the earth's crust, content is the abundantest, and its abundance occupies the 8th, accounts for 2.5% of earth's crust composition, mainly exists with the form of rhombspar, magnesite, in addition, containing magnesium about 0.13% in seawater, is inexhaustible; It is little that Mg-based hydrogen storage has proportion, specific tenacity and specific rigidity high, heat-conductivity conducting performance is good, the features such as recyclable recycling, be described as " green engineering material " of 21 century, but its chemically reactive is higher, often serious corrosion occurs in the work environment and its range of application is limited to.

The forms of corrosion of magnesium alloy has two kinds of situations usually: one is the corrosion in general environment, claims " general corrosion " or " environmental corrosion ", and also claim " chemical corrosion ", two produce " galvanic corrosion " under corrosion galvanic cell condition.This is the major way of Corrosion Behaviors of Magnesium Alloys; in order to expand the range of application of magnesium alloy; good surface treatment sfgd. just must be taked to avoid the simplest method of corrosion to be that coating prevents and environmental exposure on magnesium alloy; i.e. Coating layer technology; and chemical conversion treatment is one i.e. convenient, economic, effective process for treating surface at present, and it is other means of defence good substrate as coating, electroless plating etc. provide thereafter.After chemical reaction; bimetallic salt complex conversion film or the oxide film protection layer of one deck densification is formed at Mg alloy surface; this layer of chemical conversion film directly generates on matrix metal; form an overall structure with matrix, strengthen the solidity to corrosion of magnesium alloy and the sticking power with other coated layer material to reach.

The corrosion protection ability of the chemical conversion film of magnesium alloy is better than natural oxide film, can be magnesium alloy and good application substrate is provided, and rete is very thin, containing a large amount of micro-map crackings, be convenient to the infiltration of coating in coating process, realize conversion film and the good combination of coating, thus improve the sticking power of coating layer.The compactness of conversion film and nonactive, can intercept Magnesium and magnesium alloys and external environment and be formed and corrode microbattery, thus strengthen the solidity to corrosion of coating layer.The main chemical transforming process method adopted has at present: the rare-earth salts method techniques such as chromating, phosphoric acid salt/permanganate method, fluozirconate method, stannate method, cerium salt.

Mg alloy surface needs to carry out successively the process such as pre-treatment (cleaning, degreasing, pickling etc.), plated film, application (spray paint, plastic-blasting, metallizing etc.); the surface treatment of usually said magnesium alloy die casting refers to this road technique of plated film, and its Main Function forms the protective film with erosion resistance good with coating, plastics or metal adhesion energy at Mg alloy surface.At present, in magnesium alloy pressure-casting field, main employing is soak method surface treatment method, namely uses the surface treatment method that treatment soln is carried out.

Chemical membrane technology mainly refers to and is placed in chemical solution by magnesium alloy workpiece, utilizes chemical reaction between workpiece and chemical pretreatment solution to form a class process for treating surface of protective film at workpiece surface.

Chemically transformed film technique more ripe in prior art utilizes chromic salt, but due to chromic toxicity, be limited to use at numerous areas, although also there is the certain methods of Dai Ge to report, but or inefficiency, or erosion resistance does not reach the effect of chromium conversion film, therefore, there is certain defect.

Summary of the invention

The object of the invention is to propose the anti-corrosion conversion coating treating fluid blending process of a kind of magnesium alloy work-piece surface, the conversion coating treating fluid of this technique preparation is by the adjustment to component, do not use chromic salt, the conversion film simultaneously making the solidity to corrosion of conversion film prepared meet or exceed chromic salt to prepare.

For reaching this object, the present invention by the following technical solutions:

The anti-corrosion conversion coating treating fluid blending process of a kind of magnesium alloy work-piece surface, consisting of of this treatment solution: 85% phosphoric acid 30-34ml/L, SODIUM PHOSPHATE, MONOBASIC 34-36g/L, nitrocalcite 42-46g/L, barium carbonate 12-14g/L, phytic acid 14-16ml/L, Trisodium Citrate 18-20g/L, Seignette salt 6-8g/L, Sodium Fluoride 10-12g/L, zinc nitrate 7-9g/L, sodium-acetate 4-6g/L, ammonium meta-vanadate 3-5g/L, potassium silicofluoride 5-7g/L, ethanol 220-240ml/L, surplus is water; Described blending process is:

1) get suitable quantity of water, add 85% phosphoric acid, after stirring, add SODIUM PHOSPHATE, MONOBASIC, nitrocalcite, barium carbonate, Sodium Fluoride and zinc nitrate successively, stir 10-14 minute;

2) get metering ethanol, add phytic acid, Trisodium Citrate, Seignette salt, sodium-acetate, ammonium meta-vanadate and potassium silicofluoride successively; Stir 20-30 minute;

3) by step 2) solution add in the solution of step 1), add the water of surplus, stir after 30-40 minute, leave standstill 18-24 hour.

Beneficial effect of the present invention is:

The present invention is by the adjustment to conversion coating treating fluid component, add various ingredients, and on the basis of great many of experiments, determine component and the content for the treatment of solution, make generate conversion film in zinc, barium, calcium, phosphorus for main ingredient, and add appropriate vanadium to adjust the performance of conversion film, but not containing poisonous chromium element.Conversion film good corrosion resistance prepared by treatment solution of the present invention, under normal temperature, salt-fog test was more than 200 hours, visible, and the erosion resistance of the conversion film prepared than chromic salt is also excellent.

Embodiment

Embodiment one

The anti-corrosion conversion coating treating fluid blending process of a kind of magnesium alloy work-piece surface, consisting of of this treatment solution: 85% phosphoric acid 30ml/L, SODIUM PHOSPHATE, MONOBASIC 36g/L, nitrocalcite 42g/L, barium carbonate 14g/L, phytic acid 14ml/L, Trisodium Citrate 20g/L, Seignette salt 6g/L, Sodium Fluoride 12g/L, zinc nitrate 7g/L, sodium-acetate 6g/L, ammonium meta-vanadate 3g/L, potassium silicofluoride 7g/L, ethanol 220ml/L, surplus is water; Described blending process is: 1) get suitable quantity of water, adds 85% phosphoric acid, adds SODIUM PHOSPHATE, MONOBASIC, nitrocalcite, barium carbonate, Sodium Fluoride and zinc nitrate successively after stirring, and stirs 10 minutes;

2) get metering ethanol, add phytic acid, Trisodium Citrate, Seignette salt, sodium-acetate, ammonium meta-vanadate and potassium silicofluoride successively; Stir 20 minutes;

3) by step 2) solution add in the solution of step 1), add the water of surplus, stir after 30 minutes, leave standstill 24 hours.

Embodiment two

The anti-corrosion conversion coating treating fluid blending process of a kind of magnesium alloy work-piece surface, consisting of of this treatment solution: 85% phosphoric acid 34ml/L, SODIUM PHOSPHATE, MONOBASIC 34g/L, nitrocalcite 46g/L, barium carbonate 12g/L, phytic acid 16ml/L, Trisodium Citrate 18g/L, Seignette salt 8g/L, Sodium Fluoride 10g/L, zinc nitrate 9g/L, sodium-acetate 4g/L, ammonium meta-vanadate 5g/L, potassium silicofluoride 5g/L, ethanol 240ml/L, surplus is water; Described blending process is: 1) get suitable quantity of water, adds 85% phosphoric acid, adds SODIUM PHOSPHATE, MONOBASIC, nitrocalcite, barium carbonate, Sodium Fluoride and zinc nitrate successively after stirring, and stirs 14 minutes;

2) get metering ethanol, add phytic acid, Trisodium Citrate, Seignette salt, sodium-acetate, ammonium meta-vanadate and potassium silicofluoride successively; Stir 30 minutes;

3) by step 2) solution add in the solution of step 1), add the water of surplus, stir after 40 minutes, leave standstill 18 hours.

Embodiment three

The anti-corrosion conversion coating treating fluid blending process of a kind of magnesium alloy work-piece surface, consisting of of this treatment solution: 85% phosphoric acid 32ml/L, SODIUM PHOSPHATE, MONOBASIC 35g/L, nitrocalcite 44g/L, barium carbonate 13g/L, phytic acid 15ml/L, Trisodium Citrate 19g/L, Seignette salt 7g/L, Sodium Fluoride 11g/L, zinc nitrate 8g/L, sodium-acetate 5g/L, ammonium meta-vanadate 4g/L, potassium silicofluoride 6g/L, ethanol 230ml/L, surplus is water; Described blending process is: 1) get suitable quantity of water, adds 85% phosphoric acid, adds SODIUM PHOSPHATE, MONOBASIC, nitrocalcite, barium carbonate, Sodium Fluoride and zinc nitrate successively after stirring, and stirs 12 minutes;

2) get metering ethanol, add phytic acid, Trisodium Citrate, Seignette salt, sodium-acetate, ammonium meta-vanadate and potassium silicofluoride successively; Stir 25 minutes;

3) by step 2) solution add in the solution of step 1), add the water of surplus, stir after 35 minutes, leave standstill 21 hours.

Claims (1)

1. the anti-corrosion conversion coating treating fluid blending process of magnesium alloy work-piece surface, is characterized in that, consisting of of this treatment solution: 85% phosphoric acid 30-34ml/L, SODIUM PHOSPHATE, MONOBASIC 34-36g/L, nitrocalcite 42-46g/L, barium carbonate 12-14g/L, phytic acid 14-16ml/L, Trisodium Citrate 18-20g/L, Seignette salt 6-8g/L, Sodium Fluoride 10-12g/L, zinc nitrate 7-9g/L, sodium-acetate 4-6g/L, ammonium meta-vanadate 3-5g/L, potassium silicofluoride 5-7g/L, ethanol 220-240ml/L, surplus is water; Described blending process is:

1) get suitable quantity of water, add 85% phosphoric acid, after stirring, add SODIUM PHOSPHATE, MONOBASIC, nitrocalcite, barium carbonate, Sodium Fluoride and zinc nitrate successively, stir 10-14 minute;

2) get metering ethanol, add phytic acid, Trisodium Citrate, Seignette salt, sodium-acetate, ammonium meta-vanadate and potassium silicofluoride successively; Stir 20-30 minute;

3) by step 2) solution add in the solution of step 1), add the water of surplus, stir after 30-40 minute, leave standstill 18-24 hour.