阅读说明：本技术 一种适用于铝合金在中性盐水腐蚀介质的复配型缓蚀剂及其制备方法 (Compound corrosion inhibitor suitable for aluminum alloy in neutral salt water corrosion medium and preparation method thereof ) 是由 陈宇 于 2019-03-11 设计创作，主要内容包括：本发明属于金属材料腐蚀与防护领域,涉及一种适用于铝合金在中性盐水腐蚀介质的复配型缓蚀剂及其制备方法。本发明提出的适用于2024铝合金在中性盐水腐蚀介质的复配型缓蚀剂由苯并三唑亚麻籽油酰胺衍生物、三聚磷酸钠、钼酸钠、乳化剂OP-21和异丙醇组成。具有如下优点：一方面缓蚀剂主剂苯并三唑亚麻籽油酰胺衍生物原料来源广泛,具有环境友好性；生产工艺较简单,产物无须纯化后处理。另一方面与其它试剂复配使用能够同时抑制2024铝合金材料在中性盐水腐蚀介质的均匀腐蚀与点蚀。再次在中性盐水腐蚀介质介质中缓蚀效率达97％以上。(The invention belongs to the field of corrosion and protection of metal materials, and relates to a compound corrosion inhibitor suitable for aluminum alloy in a neutral saline corrosion medium and a preparation method thereof. The compound corrosion inhibitor suitable for 2024 aluminum alloy in neutral brine corrosion medium consists of benzotriazole linseed oleamide derivative, sodium tripolyphosphate, sodium molybdate, emulsifier OP-21 and isopropanol. Has the following advantages: on one hand, the corrosion inhibitor main agent benzotriazole linseed oil amide derivative has wide raw material source and is environment-friendly; the production process is simple, and the product does not need to be purified and post-treated. On the other hand, the compound is compounded with other reagents to be used, so that the even corrosion and pitting corrosion of the 2024 aluminum alloy material in a neutral saline corrosion medium can be inhibited at the same time. And the corrosion inhibition efficiency in a neutral saline corrosion medium is up to more than 97 percent.)

1. A compound corrosion inhibitor suitable for aluminum alloy in neutral salt water corrosion medium and a preparation method thereof are characterized in that: the compound corrosion inhibitor consists of benzotriazole linseed oleamide derivatives, sodium tripolyphosphate, sodium molybdate, an emulsifier OP-21 and isopropanol, and the mass fractions are respectively as follows: 55-70% of benzotriazole linseed oil amide derivative, 10-20% of sodium tripolyphosphate, 5-10% of sodium molybdate, 15-25% of isopropanol, and the sum of the percentage contents of all the components is 100%; the molecular structural formula of the benzotriazole linseed oil amide derivative is as follows:

wherein R includes R1, R2, R3 and R4;

2. the compound corrosion inhibitor suitable for aluminum alloy in neutral brine corrosion medium and the preparation method thereof as claimed in claim 1, wherein: the compound corrosion inhibitor is added into a 3.5 percent NaCl aqueous solution corrosion medium according to the proportion that each 100g of the corrosion medium contains 5 to 10 mg of the compound corrosion inhibitor.

3. The compound corrosion inhibitor suitable for aluminum alloy in neutral brine corrosion medium and the preparation method thereof according to claim 2 are characterized in that: the corrosion medium is 3.5% NaCl aqueous solution.

4. The compound corrosion inhibitor suitable for aluminum alloy in neutral brine corrosion medium and the preparation method thereof as claimed in claim 1, wherein: the method comprises the following steps:

the method comprises the following steps: preparing benzotriazole linseed oil amide derivatives; dissolving linseed oil and triethylene tetramine in a xylene solvent in a molar ratio of 1: 1-1: 3 in a 250 ml four-mouth bottle, adding 20-40 ml of xylene into each mole of linseed oil, slowly heating to 100-150 ℃ under the protection of nitrogen, simultaneously adding a concentrated sulfuric acid catalyst, reacting for 3-4 hours at 100-150 ℃, wherein the adding amount of the catalyst is 0.1-0.5 ml into each mole of linseed oil, distilling off xylene after the reaction is finished, cooling to room temperature to obtain a product which is a linseed oil amide derivative,

adding the linseed oleamide derivative and benzotriazole sodium into a 250 ml four-mouth bottle according to the mol ratio of 1: 1-1: 1.05, magnetically stirring and heating the four-mouth bottle to 60-80 ℃, slowly dropwise adding 80% acetic acid solution, wherein the adding amount of the acetic acid solution is 15.2 g in each mol of the linseed oleamide derivative, washing the obtained linseed oleamide derivative with distilled water after the reaction is finished, carrying out vacuum distillation, and finally obtaining a transparent liquid product, namely the benzotriazole linseed oleamide derivative,

the reaction equation is:

，

r includes R1, R2, R3 and R4;

step two: preparing a compound corrosion inhibitor;

the benzotriazole linseed oleamide derivative, the sodium tripolyphosphate, the sodium molybdate, the emulsifier OP-21 and the isopropanol are mixed according to the mass fractions of 55-70%, 10-20%, 5-10% and 15-25%, and the sum of the percentage contents of the components is 100%, so that the compound corrosion inhibitor is obtained.

Technical Field

The invention belongs to the field of corrosion and protection of metal materials, and particularly relates to a compound corrosion inhibitor suitable for aluminum alloy in a neutral saline corrosion medium and a preparation method thereof.

Background

Aluminum alloys are the most widely used non-ferrous structural materials in industry and have found a number of applications in the aerospace, automotive, mechanical, marine and chemical industries. However, aluminum is very reactive and severe corrosion can occur even in neutral brine media. Effective resistance to corrosion of aluminum alloys is therefore essential to the development of aluminum alloy applications.

The corrosion inhibitor is one of the most direct and effective methods for inhibiting metal corrosion, and a great deal of researches on the corrosion inhibitor for inhibiting aluminum alloy corrosion are carried out by a plurality of researchers at home and abroad in recent years, the corrosion inhibitor mainly comprises inorganic substances, aldehydes, a surfactant and other components, but most of compounds have unsatisfactory corrosion inhibition performance; most of the corrosion inhibitors have certain toxicity, so that the application of the corrosion inhibitors is limited, and a green environment-friendly and high-efficiency compound corrosion inhibitor for applying aluminum alloy to a strong acid corrosion medium is independently developed on the basis of the consideration of green environment protection.

The imidazoline corrosion inhibitor synthesized by using linseed oil as a raw material is reported in the literature, "evaluation of protective coating on metal surface and technical research of corrosion inhibitor", and patents 201410238332.3 and 201410238349.9, however, the linseed oil corrosion inhibitor reported in the literature or the patents is directed to corrosion inhibition protection of steel in different media (acidity, sewage and seawater), and the purification process is very complex. Therefore, the environment-friendly and efficient compound corrosion inhibitor for applying the aluminum alloy to the neutral brine corrosion medium has important economic significance and social significance by taking the linseed oil as the raw material.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides an efficient and environment-friendly compound corrosion inhibitor suitable for aluminum alloy in a neutral saline corrosion medium and a preparation method thereof, and the compound corrosion inhibitor is particularly suitable for protecting 2024 aluminum alloy in the neutral saline corrosion medium.

The invention provides a compound corrosion inhibitor suitable for aluminum alloy in a neutral brine corrosion medium, which consists of benzotriazole linseed oleamide derivatives, sodium tripolyphosphate, sodium molybdate, an emulsifier OP-21 and isopropanol, and the mass fractions are respectively as follows: 55-70% of benzotriazole linseed oil amide derivative, 10-20% of sodium tripolyphosphate, 5-10% of sodium molybdate, 215-10% of emulsifier OP-215% and 15-25% of isopropanol, wherein the sum of the percentage contents of all the components is 100%. The molecular structural formula of the benzotriazole linseed oil amide derivative is as follows:

wherein R includes R1, R2, R3 and R4;

the application of the compound corrosion inhibitor suitable for neutral brine corrosion medium is characterized in that: the compound corrosion inhibitor is added into the corrosion medium according to the proportion that every 100g of the corrosion medium contains 5-10 mg of the compound corrosion inhibitor (namely the mass fraction of the compound corrosion inhibitor in the corrosion medium is 0.005-0.01%).

Preferably, the method comprises the following steps: the corrosion medium is 3.5% NaCl water solution corrosion medium.

The preparation method of the compound corrosion inhibitor suitable for the aluminum alloy in the neutral brine corrosion medium comprises the following steps: the method comprises the following steps:

the method comprises the following steps: preparation of benzotriazole linseed oil amide derivatives.

Dissolving linseed oil and triethylene tetramine in a 250 ml four-mouth bottle according to a mol ratio of 1: 1-1: 3 in a xylene solvent, adding 20-40 ml of xylene into each mole of linseed oil, slowly heating to 100-150 ℃ under the protection of nitrogen, simultaneously adding a concentrated sulfuric acid catalyst, reacting for 3-4 hours at 100-150 ℃, wherein the adding amount of the catalyst is 0.1-0.5 ml into each mole of linseed oil, and distilling off the xylene after the reaction is finished. Cooling to room temperature to obtain the product of the linseed oil amide derivative.

Adding the linseed oil amide derivative and benzotriazole sodium into a 250 ml four-mouth bottle according to the mol ratio of 1: 1-1: 1.05, magnetically stirring and heating the four-mouth bottle to 60-80 ℃, slowly dropwise adding 80% acetic acid solution, wherein the adding amount of the acetic acid solution is 15.2 g in each mol of the linseed oil amide derivative, washing with distilled water after the reaction is finished, and then carrying out vacuum distillation to obtain a transparent liquid product, namely the benzotriazole linseed oil amide derivative.

Wherein, the linseed oil raw material is purchased from Xinte vegetable oil Co., Ltd, Zhang family, and the main components are shown in the following table:

kind of fatty acid	Content (wt.)
		Saturated fatty acid	9%-11%
Oleic acid	13%-29%
		Linoleic acid	15%-30%
Linolenic acid	40%-60%

The reaction equation is:

r includes R1, R2, R3 and R4;

step two: and (3) preparation of a compound corrosion inhibitor.

The benzotriazole linseed oleamide derivative, the sodium tripolyphosphate, the sodium molybdate, the emulsifier OP-21 and the isopropanol are mixed according to the mass fractions of 55-70%, 10-20%, 5-10% and 15-25%, and the sum of the percentage contents of the components is 100%, so that the compound corrosion inhibitor is obtained.

The invention has the beneficial effects that:

1. the invention provides a compound corrosion inhibitor suitable for aluminum alloy in neutral brine corrosion medium and a preparation method thereof, wherein benzotriazole linseed oil amide derivatives are used as a main agent of the corrosion inhibitor, the production process is simple, the raw material source is wide, linseed oil is green vegetable oil, the environment friendliness is achieved, and the water solubility of the final compound corrosion inhibitor is good;

2. the invention provides a compound corrosion inhibitor suitable for aluminum alloy in neutral salt water corrosion medium and a preparation method thereof, wherein the prepared benzotriazole linseed oleamide derivative has excellent corrosion inhibition performance on aluminum, copper and magnesium independently;

3. the invention provides a compound corrosion inhibitor suitable for aluminum alloy in neutral salt water corrosion medium and a preparation method thereof, wherein the used polyamine is triethylene tetramine, and the activity of the compound corrosion inhibitor is higher than that of diethylenetriamine;

4. the invention provides a compound corrosion inhibitor suitable for aluminum alloy in neutral salt water corrosion medium and a preparation method thereof, a synthesized final product benzotriazole linseed oleamide derivative is used as a main agent of the corrosion inhibitor without purification treatment, and a byproduct has no influence on corrosion inhibition efficiency basically;

5. the invention provides a compound corrosion inhibitor suitable for aluminum alloy in neutral brine corrosion medium and a preparation method thereof, wherein the simple benzotriazole linseed oil amide derivative has poor water solubility, and the compound of the benzotriazole linseed oil amide derivative and isopropanol obviously improves the solubility and the dispersibility of the compound corrosion inhibitor;

6. the invention provides a compound corrosion inhibitor suitable for aluminum alloy in a neutral salt water corrosion medium and a preparation method thereof, wherein the compound of a main agent of the corrosion inhibitor, sodium molybdate and sodium tripolyphosphate can inhibit the uniform corrosion and pitting corrosion of aluminum alloy materials;

7. the invention provides a compound corrosion inhibitor suitable for aluminum alloy in neutral salt water corrosion medium and a preparation method thereof, which fully exerts the synergistic effect of each component by a method of corrosion inhibitor compound synergy, and further has excellent corrosion inhibition effect in 3.5% NaCl aqueous solution corrosion medium, and the corrosion inhibition efficiency is more than 97%.

Drawings

FIG. 1: electrochemical impedance test results of the 2024 aluminum alloy in 3.5% NaCl aqueous solution without adding the compound corrosion inhibitor;

FIG. 2: electrochemical impedance test results of the 2024 aluminum alloy in 3.5% NaCl aqueous solution added with the compound corrosion inhibitor;

FIG. 3: the polarization curve test result of the 2024 aluminum alloy in 3.5% NaCl aqueous solution without adding the compound corrosion inhibitor;

FIG. 4: the polarization curve test result of the 2024 aluminum alloy in 3.5% NaCl aqueous solution added with the compound corrosion inhibitor is shown.

Detailed Description

The invention is further described below with reference to the figures and examples. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to the embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the scope of the invention as defined by the appended claims.