Green corrosion inhibitor for magnesium-lithium alloy

Abstract

The invention discloses a green corrosion inhibitor for magnesium-lithium alloy, and relates to a corrosion inhibitor. The technical problems that an existing magnesium alloy corrosion inhibitor is poor in effect and not environmentally friendly are solved. The green corrosion inhibitor for the magnesium-lithium alloy is a mixed aqueous solution of glucose and tartaric acid; wherein the concentration of the glucose is 1-35 g / L, and the concentration of the tartaric acid is 1-15 g / L. The corrosion inhibition rate of the corrosion inhibitor to the magnesium-lithium alloy reaches 85.35%-93.6%, and the corrosion inhibitor is environmentally friendly, low in cost and capable of being used in the technical field of corrosion prevention.

Description

Technical Field

[0001] The invention relates to a corrosion inhibitor. Background Art

[0002] Magnesium-lithium alloy is the lightest metal structural material with good specific strength and specific stiffness, excellent ductility, good shock and noise reduction effect, and good electromagnetic shielding. It has great application potential in the fields of aviation, aerospace, weapons, electronics, automobiles, medical equipment, etc. However, magnesium and lithium are both very active metals, so the corrosion resistance of magnesium-lithium alloy is very poor, which greatly limits its application. Adding corrosion inhibitors is a commonly used metal corrosion prevention method. Currently, the plant extract corrosion inhibitors used for magnesium alloys include tannic acid, sodium alginate, paeonol, phytic acid, etc. The article "Study on Chromium-free Phytic Acid Chemical Conversion Film of Magnesium-Lithium Alloy" published in "Functional Materials" No. 7, 2008, pp. 1134-1137, shows that after the Mg-11%Li alloy is treated in a solution mainly composed of phytic acid, its hydrogen evolution corrosion rate is reduced by about 50%. The article "Preparation and Characterization of Zinc-Manganese Phosphate Film on Magnesium-Lithium Alloy Surface" published in Volume 43, Issue 07, Pages 1764-1768 of "Rare Metal Materials and Engineering" in 2014 revealed that the corrosion rate of Mg-8%Li alloy was reduced by about 60% after being immersed in a solution mainly composed of Zn(H2PO4). The article "Corrosion Inhibition of Sodium Tannate on AZ61 Magnesium Alloy in Sodium Chloride Solution" published in Volume 43, Issue 12, Pages 22-24 of "Functional Materials" in 2010 revealed that the corrosion inhibition behavior of sodium tannate on AZ61 magnesium alloy in NaCl solution reached a maximum corrosion inhibition efficiency of 80.3%. The existing plant extract corrosion inhibitors are not effective enough, and some are not environmentally friendly. Summary of the invention

[0003] The present invention aims to solve the technical problems of poor effect and environmental pollution of existing magnesium alloy corrosion inhibitors, and to provide a green corrosion inhibitor for magnesium-lithium alloys.

[0004] The green corrosion inhibitor for magnesium-lithium alloy of the present invention is a mixed aqueous solution of glucose and tartaric acid, wherein the concentration of glucose is 1-35 g / L, and the concentration of tartaric acid is 1-15 g / L.

[0005] Furthermore, the green corrosion inhibitor for magnesium-lithium alloy is a mixed aqueous solution of glucose and tartaric acid, wherein the concentration of glucose is 10 g / L, and the concentration of tartaric acid is 10 g / L.

[0006] The green corrosion inhibitor for magnesium-lithium alloy of the present invention is a mixed solution of glucose and tartaric acid, wherein tartaric acid (C4H6O6) exists in many plants, such as grapes and tamarind, and is also one of the main organic acids in wine. Tartaric acid molecules can be adsorbed on the surface of the alloy, reducing the dissolution of Mg and Li, while reducing the adsorption and destructive effects of harmful ions in the solution, thereby protecting the alloy; the addition of glucose can reduce the effect of chloride ions in the solution on the adsorption of tartaric acid, and increase the adsorption capacity of tartaric acid on the surface of the alloy. The carbonyl group in glucose can form a metal carbonyl complex with Mg on the metal surface to prevent corrosion; at the same time, the aldehyde group in glucose has a reducing effect to prevent the oxidation of Mg and Li. The corrosion inhibition rate of the corrosion inhibitor of the present invention on magnesium-lithium alloy reaches 85.35% to 93.6%.

[0007] The green corrosion inhibitor formula for magnesium-lithium alloy of the present invention is environmentally friendly and low in cost, and can be used in the field of corrosion protection technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a photograph of the surface morphology of a Mg-Li alloy sheet immersed in a NaCl solution containing the corrosion inhibitor of Example 1;

[0009] Figure 2 This is a photo of the surface morphology of a Mg-Li alloy sheet after being immersed in a NaCl solution without a corrosion inhibitor;

[0010] Figure 3 is the polarization curve of Mg-Li alloy sheet in NaCl solution containing corrosion inhibitor and in NaCl solution without corrosion inhibitor;

[0011] Figure 4 is a photograph of the surface morphology of a Mg-Li alloy sheet after being immersed in a NaCl solution containing the corrosion inhibitor of Example 2;

[0012] Figure 5 It is the surface morphology of the Mg-Li alloy sheet after being immersed in the NaCl solution containing the corrosion inhibitor of Example 3. DETAILED DESCRIPTION

[0013] Example 1: The green corrosion inhibitor for magnesium-lithium alloy in this example is a mixed aqueous solution of glucose and tartaric acid, wherein the concentration of glucose is 10 g / L and the concentration of tartaric acid is 10 g / L. Glucose and tartaric acid are added into water and dissolved at a concentration of 10 g / L of glucose and 10 g / L of tartaric acid to obtain the green corrosion inhibitor.

[0014] 100 ml of the corrosion inhibitor prepared in Example 1 was added to 500 ml of a 3.5% by mass concentration NaCl solution, mixed evenly, and then the Mg-7% Li alloy sheet was placed in it and soaked for 10 hours, and then the Mg-Li alloy was taken out to detect the surface corrosion. At the same time, a blank test was performed, that is, the Mg-Li alloy sheet was directly placed in a 3.5% by mass concentration NaCl solution and soaked for 10 hours and then taken out. Figure 1 This is a photo of the surface morphology of a Mg-Li alloy sheet after being immersed in a NaCl solution containing a corrosion inhibitor. Figure 2 This is a photo of the surface morphology of a Mg-Li alloy sheet after being immersed in a NaCl solution without a corrosion inhibitor. Figure 1 It can be seen that the surface of the Mg-Li alloy sheet remains basically intact in the solution containing the corrosion inhibitor of Example 1. However, in the solution without the corrosion inhibitor, the surface of the sample is severely corroded with many corrosion pits.

[0015] 100 ml of the corrosion inhibitor prepared in Example 1 was added to 500 ml of a 3.5% NaCl solution, mixed evenly, and used as the electrolyte; at the same time, a 3.5% NaCl solution was used as the blank electrolyte. The Mg-Li alloy sheet was used as the working electrode, and the polarization curves of the Mg-Li alloy sheet in the 3.5% NaCl solution with and without the corrosion inhibitor were tested. Figure 3 As shown. Figure 3 It can be seen that after adding the corrosion inhibitor, the corrosion current of the alloy is greatly reduced and the corrosion potential is also increased by about 0.1V. Figure 3 The fitted corrosion current density is shown in Table 1, and it can be calculated that the corrosion inhibition rate of the corrosion inhibitor reaches 93.6%. It can be seen that the corrosion inhibitor significantly improves the corrosion resistance of the alloy.

[0016] Table 1 is Figure 3 Polarization curve fitting data

[0017]

[0018]

[0019] Example 2: The green corrosion inhibitor for magnesium-lithium alloy in this example is a mixed aqueous solution of glucose and tartaric acid, wherein the concentration of glucose is 1 g / L and the concentration of tartaric acid is 1 g / L. Glucose and tartaric acid are added into water and dissolved at a concentration of 1 g / L of glucose and 1 g / L of tartaric acid to obtain the green corrosion inhibitor.

[0020] 100 ml of the corrosion inhibitor prepared in Example 2 was added to 500 ml of a 3.5% by mass NaCl solution and mixed evenly. Then, a Mg-7% Li alloy sheet was put in and soaked for 10 hours. Then, the Mg-Li alloy was taken out and the surface corrosion was detected. Figure 4 This is the surface morphology of the alloy after being immersed in this corrosion inhibitor. It can be seen that there is only slight corrosion damage on the surface. After calculation, the corrosion inhibition rate is 85.3%.

[0021] Example 3: The green corrosion inhibitor for magnesium-lithium alloy in this example is a mixed aqueous solution of glucose and tartaric acid, wherein the concentration of glucose is 35 g / L and the concentration of tartaric acid is 15 g / L. Glucose and tartaric acid are added into water and dissolved at a concentration of 1 g / L of glucose and 1 g / L of tartaric acid to obtain the green corrosion inhibitor.

[0022] 100 ml of the corrosion inhibitor prepared in Example 3 was added to 500 ml of a 3.5% by mass NaCl solution and mixed evenly. Then, a Mg-7% Li alloy sheet was put in and soaked for 10 hours. Then, the Mg-Li alloy was taken out and the surface corrosion was detected. Figure 5 This is the surface morphology of the alloy after being immersed in this corrosion inhibitor. It can be seen that the surface is almost intact. The corrosion inhibition rate is calculated to be 91.2%.

Claims

1. A green corrosion inhibitor for magnesium-lithium alloy, characterized in that The corrosion inhibitor is a mixed aqueous solution of glucose and tartaric acid, wherein the concentration of the glucose is 1-35 g / L, and the concentration of the tartaric acid is 1-15 g / L.

2. A green corrosion inhibitor for magnesium-lithium alloy according to claim 1, characterized in that: The green corrosion inhibitor used for magnesium-lithium alloy is a mixed aqueous solution of glucose and tartaric acid; the concentration of glucose is 10g / L, and the concentration of tartaric acid is 10g / L.

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