Trivalent chromium natural colour passivation solution for processing aluminium alloy

A passivation solution, trivalent chromium technology, applied in the direction of metal material coating process, etc., can solve the problems of high price, high production cost, trivalent chromium passivation solution cannot meet market demand, etc. Low cost of use and the effect of cleaner production

Inactive Publication Date: 2011-04-06
SOUTHWEST UNIVERSITY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these products are expensive, and require heating during passivation, which has brought great cost pressure to the manufacturer; especially important, the films obtained by these passivation solutions on the surface of aluminum alloys are mostly colored, such as iridescent , blue-white and yellow, etc., and the domestic market usually requires the color of the film layer to be close to the natural color of the metal, which makes the existing trivalent chromium passivation solution unable to meet market demand
In summary, although many research institutions and manufacturers at home and abroad are researching on environmentally friendly trivalent chromium passivation solutions, and have also proposed many effective solutions and methods, these trivalent chromium passivation solutions Not only is the production cost high, but the color of the passivation film is mostly colorful
At present, there is still no trivalent chromium passivation solution that can meet the user's requirements for environmental protection, cost and passivation film color at the same time

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] All passivation solutions are prepared from commercially available raw materials. Weigh the trivalent chromium salt Cr 2 (SO 4 ) 3 .6H 2 O 1.0 g, zirconium salt ZrOCl 2 ·8H 2 O 0.05 g, nickel sulfate NiSO 4 ·6H 2 O 0.01 g, film former (NH 4 ) 4 (SO 4 ) 2 · Ce(SO 4 ) 2 4H 2 O mixed with water-based acrylic resin in any ratio 0.4 g, trisodium citrate Na 3 C 6 h 5 o 7 2H 2 O 0.4 g. Under normal temperature and pressure, dissolve trivalent chromium salt in a small amount of water, add zirconium salt and trisodium citrate while stirring, add a certain amount of water to completely dissolve, then add nickel sulfate and film-forming agent, and stir well , add water to make it 1 liter, and react naturally at room temperature for one day to get the finished product, and use sodium hydroxide to adjust the pH value to pH 4.5.

[0022] Approach:

[0023] (1) Remove grease from the surface of the aluminum alloy workpiece and clean it with tap water;

[0024] (2...

Embodiment 2

[0029] All passivation solutions are prepared from commercially available raw materials. Weigh the trivalent chromium salt CrCl 3 .6H 2 O 2.0 g, zirconium salt Zr(SO 4 ) 2 4H 2 O 0.1 g, nickel sulfate NiSO 4 ·6H 2 O 0.03 g, film-forming agent La(NO 3 ) 3 ·6H 2 O mixed with water-based acrylic resin in any ratio 0.8 g, trisodium citrate Na 3 C 6 h 5 o 7 2H 2 O 0.6 g. Under normal temperature and pressure, dissolve trivalent chromium salt in a small amount of water, add zirconium salt and trisodium citrate while stirring, add a certain amount of water to completely dissolve, then add nickel sulfate and film-forming agent, and stir well , add water to make it 1 liter, and react naturally at room temperature for one day to get the finished product. Use ammonia water to adjust the pH value to pH 5.1.

[0030] The treatment method is the same as that in Example 1, except that it is soaked in 80°C hot water for 10 seconds. The generated passivation film is white and b...

Embodiment 3

[0032] All passivation solutions are prepared from commercially available raw materials. Weigh the trivalent chromium salt Cr 2 (SO 4 ) 3 .6H 2 O and CrCl 3 .6H 2 O random ratio mixture 1.5 g, zirconium salt ZrOCl 2 ·8H 2 O 0.075 g, nickel sulfate NiSO 4 ·6H 2 O 0.02 g, film former (NH 4 ) 4 (SO 4 ) 2 · Ce(SO 4 ) 2 4H 2 O and La(NO 3 ) 3 ·6H 2 O arbitrary ratio mixture 0.6 g, trisodium citrate Na 3 C 6 h 5 o 7 2H 2 O 0.5 g. Under normal temperature and pressure, dissolve trivalent chromium salt in a small amount of water, add zirconium salt and trisodium citrate while stirring, add a certain amount of water to completely dissolve, then add nickel sulfate and film-forming agent, and stir well , add water to make it 1 liter, and react naturally at room temperature for one day to get the finished product. Use sodium hydroxide to adjust the pH value to pH 4.8.

[0033] The treatment method is the same as that in Example 1, except that the workpiece is imme...

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PUM

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Abstract

The invention relates to a trivalent chromium natural colour passivation solution for processing an aluminium alloy, comprising the following components by contents: 1-2 g/L of chromic salt, 0.05-0.1 g/L of zirconium salt, 0.01-0.03 g/L of nickel sulfate NiSO4.6H2O, 0.4-0.8 g/L of film-forming agents, 0.4-0.6 g/L of trisodium citrate Na3C6H5O7.2H2O, and the balance of water. The trivalent chromium natural colour passivation solution does not contain harmful substances, i.e. hexavalent chromium, lead, mercury, cadmium, polybrominated diphenyl ethers, polybrominated biphenyl, and the like, can be recycled, realize the clean production, passivate at normal temperature and save the energy; in addition, the aluminium alloy processed by the trivalent chromium natural-colour passivation solution has white and bright surface colour and lustre, colour approximate to the natural colour of the aluminium alloy and film neutral salt spray corrosion property meeting the national standard and can realize the substitution of the trivalent chromium passivation solution for a hexavalent chromium passivation solution.

Description

technical field [0001] The invention belongs to the technical field of metal surface treatment and anticorrosion, and in particular relates to a trivalent chromium natural color passivation solution for treating aluminum alloys. technical background [0002] Aluminum alloys are widely used in industries such as automobiles, motorcycles, aircraft and ships. However, the corrosion resistance of aluminum is weak, and anti-corrosion treatment of its surface is a necessary process. Passivation is one of the most widely used and effective anti-corrosion treatment methods. At present, most domestic enterprises choose the traditional hexavalent chromium passivation process in consideration of technology maturity and cost saving. Although the hexavalent chromium passivation film has good corrosion resistance and beautiful appearance, hexavalent chromium is a highly toxic substance, which is recognized as a carcinogen and a dangerous air pollutant. Hexavalent chromium cannot be deg...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C22/56
Inventor 彭敬东邓传跃石燕熊鹰
Owner SOUTHWEST UNIVERSITY
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