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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 complex process, long processing time and long time, and achieve improved corrosion resistance, simple passivation process and short passivation time Effect

Active Publication Date: 2009-07-15
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%) 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 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 passiva...

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 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 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 p...

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Abstract

The invention relates to a chromium-free passivation process and a passivation solution for aluminum tubes used in evaporators of refrigerators and freezers. The invention belongs to the technical field of surface treatment of aluminum materials and aims to improve the corrosion resistance of aluminum tubes used in evaporators of refrigerators and freezers. The continuously extruded aluminum tube is cooled, quickly passivated in a passivation solution at 20°C to 90°C, and then air-dried and solidified to form a passivation film on the surface of the aluminum tube. The passivation solution contains a passivation agent The mass concentration of alkyl phosphate is 1-15%, the mass concentration of silane coupling agent is 0.1-0.5%, the mass concentration of sodium silicate is 0.01-0.15%, and the rest is water. The passivated aluminum tube is dried with wind at 20-60°C and then packaged on a turntable. The process flow is simple, the cost is low, the speed is fast, the corrosion resistance of the passivated aluminum tube is greatly improved, and the agent and the passivation process are safe and environment-friendly.

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 Patents(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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