Non-chromium inactivating technique of aluminum pipe for refrigerator, ice chest evaporator and deactivation liquid

A technology of evaporator and passivation solution, which is applied in the direction of metal material coating process, etc., can solve the problems of unfavorable bending processing, long processing time, unsatisfactory effect, etc., and achieve improved corrosion resistance, short passivation time and low cost Effect

Active Publication Date: 2008-04-09
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the process requires pretreatment, anodizing, sealing and other steps, the process is complicated and takes a long time
In addition, the thicker oxide film layer is brittle and hard, which is not conducive to the bending process of the subsequent refrigerator freezer production process, and the joints between copper and aluminum are prone to leakage
Patents CN1683590 and CN1811014 propose a chromium-free process flow with titanium salt and fluoride as the main body, but the processing time is still long and the effect is not ideal

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] The aluminum tube (φ8×1mm, aluminum content > 99.7%) formed by Kangfeng continuous extrusion is water-cooled and then passed through the passivation tank. The passivation solution is filled in the tank. The mass concentration (the same below) in the passivation solution is 5-10 % lauryl phosphate, 0.4% r-aminopropyltriethoxysilane [NH 2 (CH 2 )3Si(OCH 2 CH 3 ) 3 ], 0.14% sodium silicate, and the rest is water. The temperature of the passivation solution is 40-60°C. The 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 with hot air at 80°C, and then packaged on a turntable.

[0024] Passivated aluminum tube products have been sampled and tested, and there is no obvious change after 500 hours of neutral salt spray test. It is ordinary aluminum tubes that have rust spots and pitting in 72 hours. The application performance test shows that...

Embodiment 2

[0026] The aluminum tube (φ8×1mm, aluminum content>99.7%) continuously extruded by Kangfeng is water-cooled and then passed through the passivation tank. The passivation solution is filled in the tank. The mass concentration (the same below) in the passivation solution is 10-15 % tetradecyl phosphate, 0.2% bis-[3-(triethoxy) silylpropyl] tetrasulfide (BTESPT), 0.02% sodium silicate, and the rest is water. The temperature of the passivation solution is 40-60°C. The 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 tubes are dried with hot air at 60°C, and then packaged on a turntable.

[0027] Passivated aluminum tube products have been sampled and tested, and there is no obvious change after 500 hours of neutral salt spray test, while ordinary aluminum tubes have rust spots and pitting after 72 hours. The application performance test shows that passivated alumi...

Embodiment 3

[0029] The aluminum tube (φ8×1mm, aluminum content > 99.7%) continuously extruded by Kangfeng is water-cooled and passed through the passivation tank, and the passivation solution is filled in the tank. The mass concentration (the same below) in the passivation solution is 1 to 5 % tetradecyl phosphate, 0.2% r-aminopropyltriethoxysilane [NH 2 (CH 2 )3Si(OCH 2 CH 3 ) 3 ], 0.08% sodium silicate, and the rest is water. The temperature of the passivation solution is 40-60°C. The 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 tubes are dried with hot air at 30°C, and then packaged on a turntable.

[0030] Passivated aluminum tube products have been sampled and tested, and there is no obvious change after 500 hours of neutral salt spray test, while ordinary aluminum tubes have rust spots and pitting after 72 hours. The application performance test shows that ...

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PUM

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Abstract

The invention relates to a non-chromium passivation technique and passivation solution of an aluminum pipe. The aluminum pipe is used for evaporators of ice refrigerators and ice chests. The invention belongs to the aluminum material surface treatment technical field. The invention aims at promoting the corrosion resistance of the aluminum pipe for evaporators of ice refrigerator and ice chest, etc. The continuous extrusion shape aluminum pipe is cooled off and quickly passivated in the passivation solution under the temperature from 20 DEG C to 90 DEG C. A tier of passivated film is formed on the surface of the aluminum pipe through airing and solidifying. The passivation solution contains passivant alkyl phosphate ester. The mass concentration of the passivant alkyl phosphate ester is from 1 percent to 15 percent. The mass concentration of the silane coupler is from 0.1 percent to 0.5 percent. The mass concentration of the sodium silicate is from 0.01 percent to 0.15 percent. The rest of the passivation solution is water. The passivated aluminum pipe is dried through wind under 20 DEG C to 60 DEG C and packed through the turn plate. The technique of the invention has the advantages of simple process, low cost and high speed, and the corrosion resistance of the passivated aluminum pipe is greatly promoted, and pharmaceuticals and passivation process has the performance of safety and environmental protection.

Description

technical field [0001] The invention relates to the field of surface treatment of metal materials, in particular to a chrome-free passivation process and passivation solution for aluminum tubes used in evaporators of refrigerators and freezers Background technique [0002] The evaporator is a heat exchange device commonly used in household refrigerators and plays a vital role in the operation of refrigerators or freezers. Due to price and other reasons, traditional copper tube evaporators are mostly replaced by aluminum tube evaporators. Compared with copper tubes, aluminum tubes have the advantages of light weight and low cost. However, the natural oxide layer on the surface of aluminum is very thin and has poor corrosion resistance. During the processing and use of refrigerators and freezers, due to environmental and other reasons, aluminum tubes will be corroded and perforated, resulting in refrigerant leakage. Since the aluminum tube of the refrigerator freezer evapor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C22/05
Inventor 满瑞林周亚军陈智斌李兵徐斌
Owner CENT SOUTH UNIV
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