Alkaline gold passivation solution for zinc plating

A passivation solution and electro-galvanizing technology, applied in the coating process of metal materials, etc., can solve the problems of carcinogenicity, high toxicity of hexavalent chromium, environmental and human harm, etc., and achieve strong adhesion, high corrosion resistance, and guaranteed Effect of Galvanizing Thickness

Active Publication Date: 2019-03-15
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, most production lines use chromate passivation, among which hexavalent chromium is highly toxic and easy to cause cancer, which will cause great harm to the environment and human body. Trivalent chromium will also be converted to hexavalent chromium during long-term storage and use. Chromium, the government has strictly restricted the use and discharge of chromates

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] An alkaline golden passivation solution for electroplating zinc, the pH value of the passivation solution is 8.5, its composition and content are: sodium molybdate 20g / L, ammonia 15mL / L, ammonium chloride 5g / L, sodium fluoride 5g / L L, ethanol 13mL / L, all the other are water, and the massfraction of ammoniacal liquor is 25%.

[0024] The preparation method of the alkaline gold passivation solution for zinc electroplating in this embodiment, taking 1L passivation solution as an example, specifically includes the following steps:

[0025] (1) Add deionized water with a volume equal to 50% of the passivation solution volume required for the configuration, that is, 500mL, into the beaker;

[0026] (2) Add the required amount of sodium molybdate (20g), ethanol (13mL), ammonium chloride (5g) and sodium fluoride (5g) to the deionized water in step (1), and stir until completely dissolved to obtain mixture;

[0027] (3) Add the required amount of ammonia water (15mL) to the so...

Embodiment 2

[0032] An alkaline golden passivation solution for electroplating zinc, the pH value of the passivation solution is 9.5, and its composition and content are: sodium molybdate 30g / L, ammonia water 20mL / L, ammonium chloride 8g / L, sodium fluoride 10g / L L, ethanol 20mL / L, all the other are water, and the massfraction of ammoniacal liquor is 28%.

[0033] The preparation method of the alkaline gold passivation solution for zinc electroplating in this embodiment, taking 1L passivation solution as an example, specifically includes the following steps:

[0034] (1) Add deionized water with a volume equal to 60% of the volume of passivation solution required for configuration into the beaker, that is, 600mL;

[0035] (2) Add the required amount of sodium molybdate (30g), ethanol (20mL), ammonium chloride (8g) and sodium fluoride (10g) to the deionized water in step (1), and stir until completely dissolved to obtain mixture;

[0036] (3) Add the required amount of ammonia water (20mL)...

Embodiment 3

[0041] An alkaline golden passivation solution for electroplating zinc, the pH value of the passivation solution is 9.0, and its composition and content are: sodium molybdate 25g / L, ammonia water 18mL / L, ammonium chloride 6g / L, sodium fluoride 7g / L L, ethanol 15mL / L, all the other are water, and the massfraction of ammoniacal liquor is 26%.

[0042] The preparation method of the alkaline gold passivation solution for zinc electroplating in this embodiment, taking 1L passivation solution as an example, specifically includes the following steps:

[0043] (1) Add deionized water with a volume equal to 70% of the volume of passivation solution required for the configuration into the beaker, that is, 700mL;

[0044] (2) Add the required amount of sodium molybdate (25g), ethanol (15mL), ammonium chloride (6g) and sodium fluoride (7g) to the deionized water in step (1), and stir until completely dissolved to obtain mixture;

[0045] (3) Add the required amount of ammonia water (18m...

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Abstract

The invention discloses an alkaline gold passivation solution for zinc plating, wherein the pH value of the passivation solution is 8.5- 9.5, and the composition and contents are as follows: sodium molybdate 20-30g/L, ammonia 15-20 mL/L, ammonium chloride 5-8 g/L, sodium fluoride 5-10 g/L, ethanol 13-20 mL/L, the balance being water. As the passivation solution of the invention does not contain toxic and harmful substances such as chromium, the possivation solution is novel and environmentally-friendly. The complementary,combination of ammonia water and molybdate in the passivation solution effectively avoids excessive zinc plating layer dissolusion by an acid solution, thus ensuring the thickness of the zinc plating layer and reducing the high requirement of molybdate for film thickness.The passivation solution is stable, the passivation process is simple, the corrosion resistance of the passivation film is high, the adhesion is strong, and the film thickness is uniform.

Description

technical field [0001] The invention relates to an alkaline golden passivation solution for electroplating zinc, which is mainly used in the post-treatment process of electrogalvanizing the surface of iron and steel parts. The passivation solution is chromium-free and acid-free, and belongs to the technical field of surface treatment of metal materials. Background technique [0002] Galvanizing is a surface treatment technology, in which a layer of zinc is coated on the surface of the material for the sake of beauty or rust prevention. The standard electrode potential of zinc is -0.76V. For the steel substrate, the zinc coating is an anode and has good corrosion resistance. The thickness of the coating directly affects its protective performance. After special passivation treatment, color coating or gloss protection agent, the zinc coating can enhance the protection and make the decoration more beautiful. [0003] The surface of the protected material with poor corrosion re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C22/60C25D5/48
CPCC23C22/60C25D5/48
Inventor 范云鹰雷玉娟
Owner KUNMING UNIV OF SCI & TECH
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