Environmentally-friendly electrogalvanizing passivation solution

A passivation solution, electro-galvanizing technology, applied in the direction of metal material coating process, etc., can solve the problems of carcinogenicity, toxic hexavalent chromium, environmental damage, etc.

Inactive Publication Date: 2014-01-29
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the hexavalent chromium in the passivation solution is toxic and can cause cancer, which has great damage to the environment.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0013] Embodiment 1: The components of the passivation solution of the present invention are 20g / L sodium silicate, 10mL / L hydrogen peroxide, 20g / L zinc nitrate, 6g / L sodium fluoride, 9g / L copper sulfate, 3mL / L sulfuric acid , the rest is water, the pH value is 2.

[0014] The passivation solution is used to carry out silicate passivation treatment on 80mm×80mm×1.5mm A3 low carbon steel. Before electroplating, low-carbon steel is subjected to pre-treatments such as grinding, derusting, degreasing, activation, etc., and then placed in the electroplating bath for electroplating. The bath composition and operating conditions of the galvanizing process are: ZnCl 2 80 g / L, NaCl200 g / L, boric acid 30g / L, proper amount of galvanizing additives, the pH value of the plating solution is kept at about 4.5, and the current density is 1.0 A / dm 2 , room temperature, plating time is about 20 minutes. After electroplating, the parts were taken out and cleaned with tap water, and then put i...

Embodiment approach 2

[0016] Embodiment 2: The components of the passivation solution of the present invention are 25g / L sodium silicate, 15mL / L hydrogen peroxide, 25g / L zinc nitrate, 8g / L sodium fluoride, 12g / L copper sulfate, 4mL / L sulfuric acid , the rest is water, the pH value is 2.5.

[0017] The passivation solution is used to passivate the silicate after Zn plating with a parachuting safety buckle. The safety buckle is electroplated after pretreatment (rust removal, degreasing, activation). The composition and operating conditions of the zinc-iron alloy electroplating process are: NaOH 100 g / L, ZnCl 2 10 g / L, appropriate amount of additives, pH value 12.5, cathode current density 1.7A / dm 2 , The temperature is room temperature, and the electroplating time is 30 minutes. After electroplating, take out the safety buckle and clean it with water, and then put it in with 1% HNO 3 ml / L and H 2 Stay in the light-emitting solution composed of O for 5 seconds, take out the parts and clean them ...

Embodiment approach 3

[0019] Embodiment 3: The components of the passivation solution of the present invention are 30g / L sodium silicate, 20mL / L hydrogen peroxide, 30g / L zinc nitrate, 10g / L sodium fluoride, 15g / L copper sulfate, 5mL / L sulfuric acid , the rest is water, the pH value is 3.

[0020] Use this passivation solution for passivation treatment of hardware parts such as screws and nuts after galvanizing. Metal parts are subjected to barrel plating after pretreatment (rust removal, degreasing, activation). The bath composition and operating conditions of the galvanizing process are: ZnCl 2 70 g / L, KCl190g / L, appropriate amount of additives, pH value 5.5, cathode current density 1.2 A / dm 2 , The temperature is room temperature, and the electroplating time is 60 minutes. After electroplating, take out the hardware parts and clean them with water, and then put them in with 1% HNO 3 and H 2 Stay in the light-emitting solution composed of O for 2 seconds, take out the hardware parts and wash ...

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PUM

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Abstract

The invention relates to an environmentally-friendly electrogalvanizing passivation solution, and belongs to the technical field of metal material surface treatment. The passivation solution comprises 20-30 g / L of sodium silicate, 10-20 ml / L of hydrogen peroxide, 20-30 g / L of zinc nitrate, 6-10 g / L of sodium fluoride, 9-15 g / L of copper sulfate, 3-5 ml / L of sulfuric acid and the balance of water; the pH value of the passivation solution is 2.5-3. The environmentally-friendly electrogalvanizing passivation solution completely meets the environmental protection standards such as China electroplating wastewater discharge standards and European Union RoHS (Restriction of the use of certain Hazardous Substances). The appearance of a galvanized coating treated by using the passivation solution is a uniform iridescence passivating film; the neutral salt spray test shows that the occurrence time of white rust exceeds 72 hours.

Description

technical field [0001] The invention relates to an electro-galvanizing environment-friendly passivation solution, which is mainly used in the post-treatment process of electro-galvanizing on the surface of iron and steel parts. The passivation solution is chromium-free and does not contain heavy metals and organic substances, and belongs to the technical field of metal material surface treatment. Background technique [0002] Galvanizing is one of the important means to improve the corrosion resistance of steel at home and abroad, and it is widely used in aviation, machinery, construction, transportation and other fields. However, the galvanized layer is easily corroded in the air, especially in a humid environment. In order to meet the corrosion resistance requirements in harsh environments, passivation treatment is required to meet the corrosion resistance standards. [0003] Now, the most commonly used industrial passivation treatment process is chromate passivation. The...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C22/34
Inventor 范云鹰金海玲蒋业华
Owner KUNMING UNIV OF SCI & TECH
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