Bolt surface corrosion prevention method

An anti-corrosion and bolting technology, applied in the field of electrochemical surface treatment, can solve problems such as unsatisfactory adhesion and difficult peeling of the oxide layer, and achieve the effects of good surface strength, outstanding corrosion resistance, and improved efficiency

Inactive Publication Date: 2015-12-30
CHENGDU SCI & TECH DEV CENT CHINA ACAD OF ENG PHYSICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the bolt workpieces pretreated by these processes cannot meet the requirements of adhesion after electroplating. Due to the gap barrier characteristics of the bolt itself, the oxide layer in the gap on the surface

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Embodiment 1 In 45# bolt surface ionic liquid electrodeposition aluminum-manganese alloy coating, concrete steps are as follows:

[0038] (1): Use one-step degreasing method to degrease and degrease 45# bolts. The degreasing agent is sodium hydroxide 20g / L, sodium carbonate 10g / L, trisodium phosphate 15g / L and the rest of deionized water. Put the 45# bolt workpiece as the cathode, and the 304 stainless steel plate as the anode, put it into the electrolyte at a temperature of 60°C, and apply a current density of 10mA / cm 2 , electrolytic degreasing 30s. Subsequently, the 45# bolt workpiece that has been electrolytically degreased is immersed in 20% HCl and cleaned for 5 minutes to preliminarily remove the oxide film on the surface of the substrate.

[0039] (2) The above-mentioned 45# bolts processed through the steps are immersed in the activation solution to carry out anodic activation treatment, with the 45# bolt workpiece as the anode, and the Al plate (purity 99.9wt...

Embodiment 2

[0046] Embodiment 2: ionic liquid electrodeposits aluminum-manganese alloy coating on the surface of 304 stainless steel bolts, the specific steps are as follows:

[0047] (1): Use one-step degreasing method to degrease and degrease 304 stainless steel bolts. The degreasing agent is sodium hydroxide 30g / L, sodium carbonate 30g / L, trisodium phosphate 5g / L and the rest of deionized water. Put the 304 stainless steel bolt workpiece as the cathode, and the 304 stainless steel plate as the anode, put it into the electrolyte at a temperature of 60°C, and apply a current density of 5mA / cm 2 , electrolytic degreasing 1min. Subsequently, the 304 stainless steel bolt workpiece that has been electrolytically degreased is immersed in 10% HCl and cleaned for 10 minutes to initially remove the oxide film on the surface of the substrate.

[0048] (2) The above-mentioned 304 stainless steel bolts processed through the steps are immersed in the activation solution to carry out anodic activati...

Embodiment 3-6

[0054] The 304 stainless steel bolt workpiece was treated with the same pretreatment method as in Example 2, and then the surface deposition electroplating was performed using the same electroplating method. There are only some differences in the temperature and composition ratio of the ionic liquid during the electroplating process, the current density and time of electroplating, etc., see Table 1 below for details.

[0055] Table 1

[0056]

[0057] *The composition ratio is the molar ratio of 1-methyl-3-ethylimidazole chloride and AlCl3

[0058] As can be seen from the above examples, when the control current density 6-10mA / cm 2 , when the ratio of aluminum trichloride and EMIC in the selected ionic liquid is 1 to 2:1, when MnCl 2 The concentration is 0.2-0.3mol / L, and the obtained coating is amorphous. When the MnCl2 concentration is 0.1mol / L, 20mA / cm 2 High-current electroplating can obtain a crystalline phase coating. Control the current density at 6-10mA / cm 2 ,...

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Abstract

The invention discloses a bolt surface corrosion prevention method. The method comprises procedures as follows: a bolt is subjected to surface treatment including degreasing, deoiling and oxidation film removal with a conventional method; anode activation is performed on an ionic liquid, and the oxidation film on the surface of the bolt is completely removed; the ionic liquid is subjected to electro-deposition, an aluminum-manganese plating is formed, the bolt is subjected to constant-current electro-deposition with a barrel plating method, an aluminum-manganese alloy plating is formed, a plating solution comprises a bis-substituted imidazolium chloride-aluminum chloride type ionic liquid and manganese salt, a two-electrode system is adopted, the bolt is taken as a working electrode, a metal Al plate is taken as a counter electrode, the anodic current density is 6-20 mA/cm<2>, and the plating time is 0.5-2 h. With the adoption of the method, the bolt can have a clean surface without an oxidation layer in advance, the aluminum-manganese alloy plating is obtained through electro-deposition in a barrel plating manner, a process is simple, the operation is convenient, the energy consumption is low, no pollution is produced to the environment, platings are uniformly distributed on the part surface and well combined with the surface, higher corrosion resistance performance is achieved, batch production can be realized, and a wide application prospect is achieved.

Description

technical field [0001] The invention relates to a metal surface anticorrosion method, in particular to a method for electroplating an aluminum-manganese alloy anticorrosion coating on the surface of a bolt by using an ionic liquid, and belongs to the field of electrochemical surface treatment. Background technique [0002] Bolts are widely used in construction, home appliances, automobiles, and petrochemical industries. However, under some extremely harsh conditions, such as marine environments, the surface of bolts is prone to electrochemical reactions, resulting in rust and corrosion. Rusty carbon steel bolts reduce the structural strength quickly, which directly affects the safety and reliability of the equipment. Moreover, during the regular maintenance process, the corroded bolts are very easy to slip due to the decrease in the strength of the angular structure, and sometimes they have to be disassembled by violent destruction, which increases the labor intensity and en...

Claims

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Application Information

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IPC IPC(8): C25D3/56C25D5/36C25F1/06
Inventor 廖成丁晶晶江奕东黄迎春郑兴平凌国平梅军刘焕明
Owner CHENGDU SCI & TECH DEV CENT CHINA ACAD OF ENG PHYSICS
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