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Chromium-free passivation method of aluminum pipe for evaporator of refrigerator or freezer and passivation solution thereof

A chromium-free passivation and evaporator technology, applied in the direction of metal material coating process, etc., can solve the problems affecting the vulcanization adhesion of the evaporator aluminum tube and the aluminum plate, and the processing time is short, and achieves low cost, short passivation time, Simple process effect

Active Publication Date: 2011-08-03
CENT SOUTH UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Patent CN101158037A proposes a chromium-free passivation process for aluminum tubes used in evaporators of refrigerators and freezers. The processing time is short, and the on-line passivation of Kangfeng continuous extrusion molding process is realized, and the corrosion resistance of aluminum tubes is significantly improved. However, the passivated product The surface is too smooth, affecting the vulcanization adhesion between the evaporator aluminum tube and the aluminum plate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The 1060 aluminum tube (φ7.8×1mm) formed by online Kangfeng continuous extrusion is water-cooled and passed through the passivation tank for passivation. The mass concentration and composition of the passivation solution in the passivation tank (the same below) are: 4% vinyl Tris(β-methoxyethoxy)silane, 0.4% dodecyl phosphate, 0.3% sodium silicate, and the solvent is 4% 95% ethanol plus water. Using HNO 3 Adjust the pH to 2.0, control the temperature in the passivation tank to 40° C., and the on-line passivation time to 8 seconds. The passivation tank is equipped with a stirring and constant temperature control system. The solution in the tank is circulated through the pump and the pipeline. The passivated aluminum tube is dried and cured at 80°C for 3 to 5 minutes, and then packaged on a turntable; there is no evaporator for the aluminum tube and The problem of vulcanization sticking of the aluminum plate arises.

[0017] Passivated aluminum tube products have been s...

Embodiment 2

[0019] The 1060 aluminum tube (φ8.0×1mm) formed by online Kangfeng continuous extrusion is water-cooled and passed through the passivation tank for passivation. The mass concentration and composition of the passivation solution in the passivation tank (the same below) are: 5% vinyl Tris(β-methoxyethoxy) silane, 0.3% dodecyl phosphate and 0.3% benzotriazole, the solvent is 5% 95% ethanol plus water. Using HNO 3 Adjust the pH to 2.5, control the temperature in the passivation tank to 35° C., and the on-line passivation time to 5 seconds. The passivation tank is equipped with a stirring and constant temperature control system, and the solution in the tank circulates through pumps and pipelines. The passivated aluminum tube is dried and cured at 90°C for 5-8 minutes, and then packaged on a turntable; there is no problem of vulcanization and adhesion between the evaporator aluminum tube and the aluminum plate.

[0020] Passivated aluminum tube products have been sampled and teste...

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PUM

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Abstract

The invention discloses a chromium-free passivation method of an aluminum pipe for an evaporator of a refrigerator or a freezer and a passivation solution thereof, belonging to the technical field of surface treatment of aluminum materials. The invention aims to improve the corrosion resistance of the aluminum pipe for the evaporator and the like of the refrigerator or the freezer. A passivation process is carried out on a CANFORM continuous extrusion aluminum pipe production line in an on-line way, the aluminum pipe formed by CANFORM continuous extrusion passes through a passivation groove after being water-cooled, and the passivation solution which has the components of passivator, assistant and solvent is filled into the groove, wherein vinyltris(beta-methoxyethoxy)silane the mass concentration of which is 1-15% is used as the passivator I, and dodecyl phosphate the mass concentration of which is 0.2-0.5% is used as the passivator II; benzotriazole or sodium silicate the concentration of which is 0.01-0.3% is used as the assistant; the mixture of water and 95% ethanol, the concentration of which is 3-8%, is used as the solvent; the passivation pH is 1.5-3.5, the passivation temperature is 35-50 DEG C, and the passivation time is 1-15 seconds; and the passivated aluminum pipe is packed with a rotating disk after being aired at 40-100 DEG C. The invention has the advantages of simple technical processes, low cost, high speed, on-line passivation, great improvement of corrosion resistance of the passivated aluminum pipe, and safety and environmental protection of medicaments and passivation processes.

Description

technical field [0001] The invention belongs to the field of metal material surface treatment, and in particular relates to a chromium-free passivation method and a passivation solution for aluminum tubes used in evaporators of refrigerators and freezers. Background technique [0002] Aluminum is widely used as refrigerator and freezer evaporator material due to its light weight and low price. Since the oxide film naturally formed on the surface of the aluminum tube is thin and not dense, long-term exposure to corrosive media or environments can easily cause pitting corrosion of the aluminum tube, resulting in refrigerant leakage, causing the entire refrigerator or freezer to fail or even be scrapped. It is a waste of resources and also causes serious pollution to the environment. [0003] Anticorrosion treatment on the surface of aluminum tube is an important way to improve its corrosion resistance, while the traditional treatment method is chromate passivation treatment, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C22/03
Inventor 满瑞林梁永煌蒋继明陈智斌肖围张春燕刘红健
Owner CENT SOUTH UNIV
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