阅读说明：本技术 一种适用于az91d镁合金在中性盐水介质的复配缓蚀剂及其制备方法 (Compound corrosion inhibitor suitable for AZ91D magnesium alloy in neutral saline water 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,涉及一种适用于中性盐水腐蚀介质的AZ91D镁合金的复配缓蚀剂及其制备方法。本发明提出的适用于中性盐水腐蚀介质的AZ91D镁合金的复配缓蚀剂由苯并三唑亚麻籽油酰胺衍生物、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且亚麻籽油为绿色植物油,具有环境友好性；合成方法简单,产物无须纯化后处理。另一方面与其它试剂复配使用,可明显降低缓蚀剂用量,减少成本,在中性盐水腐蚀介质中缓蚀效率高达98％以上。(The invention belongs to the field of corrosion and protection of metal materials, and relates to a compound corrosion inhibitor of AZ91D magnesium alloy suitable for neutral brine corrosion medium and a preparation method thereof. The compound corrosion inhibitor of the AZ91D magnesium alloy suitable for neutral brine corrosion medium consists of benzotriazole linseed oleamide derivatives, sodium molybdate, an 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 linseed oil is green vegetable oil and has environmental friendliness; the synthesis method is simple, and the product does not need to be purified and post-treated. On the other hand, the corrosion inhibitor is compounded with other reagents for use, so that the consumption of the corrosion inhibitor can be obviously reduced, the cost is reduced, and the corrosion inhibition efficiency in a neutral saline corrosion medium is up to more than 98%.)

1. A compound corrosion inhibitor suitable for AZ91D magnesium alloy in neutral brine corrosion medium and a preparation method thereof are characterized in that: the compound corrosion inhibitor consists of benzotriazole linseed oleamide derivatives, 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 molybdate, 215-10% of emulsifier OP-215%, and 15-25% of absolute ethyl alcohol, 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;

。

2. the compound corrosion inhibitor suitable for AZ91D magnesium alloy in neutral brine corrosion medium and the preparation method thereof in claim 1 are characterized in that: 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 AZ91D magnesium alloy in neutral brine corrosion medium and the preparation method thereof according to claim 2, wherein the compound corrosion inhibitor is characterized in that: the corrosion medium is 3.5% NaCl aqueous solution.

4. The compound corrosion inhibitor suitable for AZ91D magnesium alloy in neutral brine corrosion medium and the preparation method thereof in claim 1 are characterized in that: the method comprises the following steps:

the method comprises the following steps: preparation of benzotriazole linseed oleamide 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 linseed oleamide derivatives and benzotriazole sodium into a 250 ml four-mouth bottle according to a 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 linseed oleamide derivatives, washing the obtained product with distilled water after the reaction is finished, and then carrying out vacuum distillation to obtain a transparent liquid product, namely benzotriazole linseed oleamide derivatives, wherein the reaction equation is as follows:

r includes R1, R2, R3 and R4;

step two: preparation of the compound corrosion inhibitor:

the benzotriazole linseed oleamide derivative, 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 AZ91D magnesium alloy in a neutral saline corrosion medium and a preparation method thereof.

Background

The magnesium alloy has the advantages of small relative density, high specific strength, good processing, welding and damping properties, stable size, low price, recyclability and the like, and has wide application prospect in the fields of automobiles, electronics, machinery, aviation, aerospace and the like. However, the electrode potential of the magnesium alloy is very negative, the chemical property is active, and the magnesium alloy is very easy to corrode in humid atmosphere or neutral saline solution, so that the effective inhibition of the corrosion of the magnesium alloy is very necessary for the development of the application of the magnesium alloy.

The corrosion inhibition technology is one of the most widely applied methods in the corrosion prevention technology, and in recent years, a great deal of research is carried out on corrosion inhibitors for inhibiting the corrosion of magnesium alloys by many researchers at home and abroad, wherein most of the corrosion inhibitors developed by the researchers comprise components such as phosphate, chromate and the like. The industry has been reducing its use due to the greater environmental pollution of phosphates and chromates. At present, the corrosion inhibition effect of AZ91D magnesium alloy is reported to be compounded with polyaspartic acid and thiourea as the corrosion inhibitor of the magnesium alloy, however, the corrosion inhibition efficiency is only 81.7%. Based on the consideration of green and environmental protection, a green and environment-friendly high-efficiency compound corrosion inhibitor for applying AZ91D magnesium alloy to neutral brine corrosion medium is independently developed.

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", patents 201410238332.3 and 201410238349.9, however, the linseed oil corrosion inhibitors reported in the literature or the patents are all used for corrosion inhibition protection of carbon steel in different media (acidity, sewage and seawater), the purification process is very complex, and no report is made on corrosion inhibition of AZ91D magnesium alloy. Therefore, the green, environment-friendly and efficient compound corrosion inhibitor for the AZ91D magnesium alloy applied to neutral brine corrosion medium has important economic and social significance by using 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 AZ91D magnesium alloy in neutral saline corrosion medium and a preparation method thereof, and the compound corrosion inhibitor is particularly suitable for the protection of AZ91D magnesium alloy in neutral saline corrosion medium.

The invention provides a compound corrosion inhibitor suitable for AZ91D magnesium alloy in neutral brine corrosion medium, which comprises benzotriazole linseed oleamide derivative, sodium molybdate, emulsifier OP-21 and isopropanol, and the mass fractions are respectively: 55-70% of benzotriazole linseed oil amide derivative, 10-20% 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 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.

The preparation method of the compound corrosion inhibitor suitable for 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:

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

The benzotriazole linseed oleamide derivative, 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 AZ91D magnesium alloy in neutral brine corrosion medium and a preparation method thereof, wherein the production process of benzotriazole linseed oil amide derivatives is simple, the raw material source is wide, linseed oil is green vegetable oil, the compound corrosion inhibitor is environment-friendly, and the final compound corrosion inhibitor has good water solubility;

2. the invention provides a compound corrosion inhibitor suitable for AZ91D magnesium alloy in neutral brine corrosion medium and a preparation method thereof, wherein the prepared benzotriazole linseed oil amide derivative has excellent corrosion inhibition performance on magnesium, aluminum and zinc independently;

3. the invention provides a compound corrosion inhibitor suitable for AZ91D magnesium alloy in neutral brine 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 AZ91D magnesium alloy in neutral brine corrosion medium and a preparation method thereof, the synthesized final product benzotriazole linseed oleamide derivative corrosion inhibitor does not need purification treatment, and the by-product has no influence on corrosion inhibition efficiency;

5. the invention provides a compound corrosion inhibitor suitable for AZ91D magnesium 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 corrosion inhibitor is compounded with an emulsifier OP-21 and isopropanol to obviously improve the solubility and the dispersibility;

6. the invention provides a compound corrosion inhibitor suitable for AZ91D magnesium alloy in neutral brine corrosion medium and a preparation method thereof, wherein the compound of benzotriazole linseed oleamide derivative and sodium molybdate can inhibit the uniform corrosion and pitting corrosion of AZ91D magnesium alloy material;

7. the invention provides a compound corrosion inhibitor suitable for AZ91D magnesium alloy in neutral saline corrosion medium and a preparation method thereof, which fully exerts the synergistic effect of each component by a method of corrosion inhibitor compound synergy, further has excellent corrosion inhibition effect in 3.5% NaCl aqueous solution corrosion medium, and the corrosion inhibition efficiency is more than 97%.

8. The invention provides a compound corrosion inhibitor suitable for AZ91D magnesium alloy in neutral brine corrosion medium and a preparation method thereof, wherein the compound method is simple, and the synergistic effect obviously reduces the dosage of each corrosion inhibitor in the compound corrosion inhibitor compared with single use, thereby having lower production cost; the compound corrosion inhibitor has the characteristic of environmental friendliness, and does not influence the normal operation of equipment.

Drawings

FIG. 1: the electrochemical impedance test result of the AZ91D magnesium alloy in a 3.5% NaCl aqueous solution corrosion medium without adding a compound corrosion inhibitor;

FIG. 2: the electrochemical impedance test result of the AZ91D magnesium alloy in a 3.5% NaCl aqueous solution corrosion medium added with the compound corrosion inhibitor is shown;

FIG. 3: the Tafel polarization curve test result of the AZ91D magnesium alloy in a 3.5% NaCl aqueous solution corrosion medium without adding a compound corrosion inhibitor;

FIG. 4: the Tafel polarization curve test result of the AZ91D magnesium alloy in a 3.5% NaCl aqueous solution corrosion medium added with a compound corrosion inhibitor.

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.