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Brass surface passivation solution and passivation method

A brass, chromium-free passivation technology, applied in the direction of metal material coating process, etc., can solve the problems of easy corrosion, discoloration and other problems, and achieve the effect of easy waste liquid

Inactive Publication Date: 2011-04-06
JIANGXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Solve the problem that brass is easily corroded or discolored when it encounters acidic or alkaline corrosive media, or in high temperature and high humidity environments

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 1. Test material: brass, the main chemical composition (Wt%) is: 72.8% Cu, 24.6% Zn, 2.5% Al, and the rest are impurities. The sample size is: 30mm×20mm×0.2mm.

[0026] 2. Process flow: sample cutting → degreasing → tap water rinsing → pickling → tap water rinsing → chemical polishing → tap water rinsing → passivation → tap water rinsing → drying, the specific steps are:

[0027] (1) Cut the brass sheet into a sample with a size of 30mm×20mm×0.2mm. Take a clean bristle brush to clean the dirt on the surface of the brass test piece.

[0028] (2) There will be oil on the surface of the brass sample after processing, which must be removed. Put it in an alkaline degreasing solution to remove oil. The degreasing process is carried out in an ultrasonic cleaner. Take it out after a certain period of time and rinse it with tap water. .

[0029] (3) Put the degreased brass sample in dilute sulfuric acid for pre-pickling to remove the scale on the surface of the sample, take i...

Embodiment 2

[0039] 1. Test material: same as embodiment 1.

[0040] 2. Technological process: with embodiment 1.

[0041] 3. Alkaline degreasing formula: same as Example 1.

[0042] 4. Pickling and descaling solution: same as in Example 1.

[0043] 5. Chemical polishing liquid formula: with embodiment 1.

[0044] 6. passivation solution formula of the present invention: phytic acid 4ml / L, hydrogen peroxide 9ml / L, boric acid 1g / L, macrogol-400 5ml / L, sodium silicate (Na 2 SiO 3 9H 2 O) 10g / L, the passivation temperature is 35-40°C, the pH value is 2-3 (adjusted with sulfuric acid or sodium hydroxide), and the passivation time is 60s.

[0045]

Embodiment 3

[0047] 1. Test material: same as embodiment 1.

[0048] 2. Technological process: with embodiment 1.

[0049] 3. Alkaline degreasing formula: same as Example 1.

[0050] 4. Pickling and descaling solution: same as in Example 1.

[0051] 5. Chemical polishing liquid formula: with embodiment 1.

[0052] 6. passivation solution formula of the present invention: phytic acid 5ml / L, hydrogen peroxide 9ml / L, boric acid 6g / L, macrogol-400 16ml / L, sodium silicate (Na 2 SiO 3 9H 2 O) 5g / L, the passivation temperature is 35-40°C, the pH value is 2-3 (adjusted with sulfuric acid or sodium hydroxide), and the passivation time is 60s.

[0053]

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PUM

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Abstract

The invention discloses brass surface passivation solution and a passivation method. The formula in a chrome-free passivation process comprises 2.5 to 6ml / L of phytic acid, 9 to 12ml / L of hydrogen peroxide, 1 to 7g / L of boric acid, 2 to 16ml / L of polyethylene glycol-400 and 1 to 10g / L of additive. The passivation temperature is 35 to 45 DEG C; the pH value is 2 to 4; and the passivation time is 55 to 65 seconds. A brass sample is placed in the passivation solution, and then the corrosion resistance of a brass surface can be obviously improved and the corrosion resistance of the brass is a little better than that of a bichromate passivated film. The passivation method is expected to substitute the bichromate passivation technology and has a wide application prospect.

Description

technical field [0001] The invention relates to a chromium-free passivation technology on the surface of brass, which belongs to the technical field of metal corrosion and protection. [0002] Background technique [0003] Brass has excellent electrical conductivity and processing properties, and is widely used in industrial production and daily life. Its standard potential is relatively positive, and there is no obvious corrosion phenomenon in dry atmosphere, but it is sensitive in humid environment, industrial atmosphere and high temperature conditions, resulting in discoloration and corrosion during production, storage, transportation and use. Therefore, it is necessary to carry out anti-corrosion treatment, and the more economical and convenient method is to carry out passivation treatment on the surface of brass. [0004] The traditional process uses chromate passivation to protect copper alloys from corrosion. However, with the improvement of people's awareness of en...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C22/02
Inventor 蔡薇柳瑞清刘仁辉许洪胤李莉吴语
Owner JIANGXI UNIV OF SCI & TECH
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