阅读说明：本技术 一种不锈钢钝化剂及其制备方法 (Stainless steel passivator and preparation method thereof ) 是由 付国爱 于 2020-06-09 设计创作，主要内容包括：一种不锈钢钝化剂,按质量百分数计,包括如下组分：柠檬酸5-30％,植酸5-20％,过氧化二异丙苯1-10％,有机硅1-20％,亚氨基二琥珀酸四钠0.3-0.6％,余量为去离子水。一种不锈钢钝化剂由以下方法制备而成：按照上述配比,将柠檬酸、植酸、过氧化二异丙苯、亚氨基二琥珀酸四钠和水性丙烯酸聚硅氧烷加入到去离子水中,升温到50℃,搅拌20min,形成钝化剂。本发明的不锈钢钝化剂在不锈钢表面形成致密的保护膜,有效延长不锈钢工件的服役寿命。(A stainless steel passivator comprises the following components in percentage by mass: 5-30% of citric acid, 5-20% of phytic acid, 1-10% of dicumyl peroxide, 1-20% of organic silicon, 0.3-0.6% of imino disuccinic acid tetrasodium and the balance of deionized water. The stainless steel passivator is prepared by the following steps: according to the proportion, citric acid, phytic acid, dicumyl peroxide, iminodisuccinic acid tetrasodium and waterborne acrylic polysiloxane are added into deionized water, the temperature is raised to 50 ℃, and the mixture is stirred for 20min to form the passivator. The stainless steel passivator disclosed by the invention forms a compact protective film on the surface of stainless steel, so that the service life of a stainless steel workpiece is effectively prolonged.)

1. A stainless steel passivator is characterized in that: the composite material comprises the following components in percentage by mass:

5 to 30 percent of citric acid

5 to 20 percent of phytic acid

Dicumyl peroxide 1-10%

1 to 20 percent of organic silicon

0.3 to 0.6 percent of imino disuccinic acid tetrasodium

The balance being deionized water.

2. The stainless steel passivator of claim 1 wherein: the content of citric acid is 10-20%; the content of phytic acid is 5-10%; the content of dicumyl peroxide is 2-5%.

3. The stainless steel passivator of claim 1 wherein: the organosilicon is water-based acrylic polysiloxane, and the content is 3-8%.

4. The stainless steel passivator of claim 1 wherein: the stainless steel passivator is prepared by the following steps: according to the proportion, citric acid, phytic acid, dicumyl peroxide, tetrasodium iminodisuccinate and organic substances are added into deionized water, the temperature is raised to 50 ℃, and the mixture is stirred for 20min to form the passivator.

5. The use of a stainless steel passivator according to claim 1, wherein: the method is applied to stainless steel surface passivation.

Technical Field

The invention belongs to the technical field of stainless steel surface passivation treatment, and particularly relates to a stainless steel passivator, a preparation method and application thereof.

Background

Passivation is a process that converts the metal surface to a state that is not easily oxidized, thereby retarding the corrosion rate of the metal. The passivation of the stainless steel material is to generate a very thin, compact and good-covering-performance passivation film (oxidation film) which can be firmly attached on the metal surface; this film exists as a separate phase, usually a compound of oxygen and a metal.

In the traditional stainless steel passivation process, a chromium-acid system is generally adopted to passivate stainless steel, but the chromium-acid system is gradually eliminated due to increasing environmental protection, and the fluorozirconate system or the fluorotitanate system is mostly applied at present, but the two systems have poor stability, and working liquid is easy to generate insoluble suspended matters to influence the formation of a passivation film, so that the corrosion resistance of a base material is uneven and poor, the salt spray test time for carrying out the chromating treatment on the stainless steel by adopting the existing fluorozirconate system or fluorotitanate system is only 48-120 hours, and the bath liquid needs to be replaced every half month, so that the bath liquid is relatively wasted and the use cost is relatively high.

Patent CN110670058A discloses a chromium-free passivator, which comprises the following components in percentage by weight: lanthanum chloride: 8.0-10.0%, corrosion inhibitor: 5.0-7.5%, cerium chloride: 3.1-5.6%, metal salt: 3.1-4.5%, water-based acrylic resin: 2.5-3.0%, fluorozirconic acid: 1.1-1.5%, complexing agent: 0.5-0.6%, tannic acid: 0.3-0.7%, cellulose ether: 0.1-0.2% and deionized water: 66.4 to 76.3 percent. According to the system, expensive rare earth metal salt is used as a passivator, fluozirconic acid is used as a film forming aid, and although the salt spray resistance test time is prolonged, the chromium-free passivator still needs to replace bath solution once a month, so that the environment pollution is easily caused, and the sustainable development is not facilitated.

Disclosure of Invention

In view of the problems, the invention aims to provide a stainless steel passivator and a preparation method thereof.

In order to solve the technical problems, the invention adopts the following technical scheme: a stainless steel passivator comprises the following components in percentage by mass:

5 to 30 percent of citric acid

5 to 20 percent of phytic acid

Dicumyl peroxide 1-10%

1 to 20 percent of organic silicon

0.3 to 0.6 percent of imino disuccinic acid tetrasodium

The balance of deionized water

In the composition of the passivating agent, the content of citric acid is preferably 10-20%; the content of the phytic acid is preferably 5-10%; the content of dicumyl peroxide is 2-5%.

Preferably, the organosilicon is water-based acrylic polysiloxane with the content of 3-8%.

The stainless steel passivator is prepared by the following steps: according to the proportion, citric acid, phytic acid, dicumyl peroxide, iminodisuccinic acid tetrasodium and waterborne acrylic polysiloxane are added into deionized water, the temperature is raised to 50 ℃, and the mixture is stirred for 20min to form the passivator.

Cleaning a stainless steel workpiece with deionized water, polishing and removing dirt with sand paper, then ultrasonically cleaning in an ethanol solution, cleaning in a hydrochloric acid solution to remove a surface oxidation film, and finally washing with deionized water. Firstly, heating the prepared passivator to 50 ℃, putting the pretreated stainless steel workpiece into the passivator, passivating for 25 minutes, and drying the sample after the passivation is finished. The treated workpiece has the original color and is subjected to corrosion resistance and neutral salt spray tests.

The invention has the following beneficial effects:

the citric acid can preferentially dissolve the iron element in the matrix, and the strong oxidizing property of dicumyl peroxide enables the chromium element enriched in the stainless steel matrix to be oxidized to form a compact oxide film to participate in the passivation process. The phytic acid has strong complexing ability, can be chelated with metal ions on the surface of the stainless steel, forms insoluble precipitates on the surface of the stainless steel, and further forms a protective film; the iminodisuccinic acid tetrasodium salt is complexed with metal ions on the surface of the stainless steel to form insoluble precipitates on the surface of the stainless steel, and the insoluble precipitates and an organic film formed by the waterborne acrylic polysiloxane generate a synergistic effect, so that the stainless steel is better protected from being corroded. The stainless steel passivator disclosed by the invention forms a compact protective film on the surface of stainless steel, so that the service life of a stainless steel workpiece is effectively prolonged.

Detailed Description