阅读说明：本技术 钢铁常温发黑剂及其制备方法和发黑方法 (Steel normal-temperature blackening agent, preparation method thereof and blackening method ) 是由 于玉城 王振玲 罗从众 徐果 于 2019-10-15 设计创作，主要内容包括：本发明涉及钢铁常温发黑剂及其制备方法和发黑方法,属于金属材料腐蚀防护技术领域。所述钢铁常温发黑剂以水为溶剂并包含以下组分：亚硒酸1-5g/L,硫酸铜1-5g/L,硝酸镍1-5g/L,磷酸二氢锌1-4g/L,磷酸1-5mL/L,柠檬酸1-3g/L,焦磷酸钾0.5-1.5g/L,OP-10乳化剂0.5-1.5mL/L和氧化石墨烯0.04-0.07g/L。本文主要通过在硒-铜常温发黑体系中添加一定量的氧化石墨烯,以此得到一种在防护和装饰上更加优良的新型钢铁常温发黑剂。(The invention relates to a normal-temperature steel blackening agent, a preparation method and a blackening method thereof, belonging to the technical field of corrosion protection of metal materials. The steel normal-temperature blackening agent takes water as a solvent and comprises the following components: 1-5g/L selenious acid, 1-5g/L copper sulfate, 1-5g/L nickel nitrate, 1-4g/L zinc dihydrogen phosphate, 1-5mL/L phosphoric acid, 1-3g/L citric acid, 0.5-1.5g/L potassium pyrophosphate, 0.5-1.5mL/L OP-10 emulsifier and 0.04-0.07g/L graphene oxide. A certain amount of graphene oxide is added into a selenium-copper normal-temperature blackening system, so that a novel steel normal-temperature blackening agent which is more excellent in protection and decoration is obtained.)

1. the normal-temperature steel blackening agent is characterized by taking water as a solvent and comprising the following components: 1-5g/L selenious acid, 1-5g/L copper sulfate, 1-5g/L nickel nitrate, 1-4g/L zinc dihydrogen phosphate, 1-5mL/L phosphoric acid, 1-3g/L citric acid, 0.5-1.5g/L potassium pyrophosphate, 0.5-1.5mL/L OP-10 emulsifier and 0.04-0.07g/L graphene oxide.

2. The steel normal temperature blackening agent of claim 1, wherein the steel normal temperature blackening agent comprises the following components: 1-5g/L selenious acid, 1-5g/L copper sulfate, 1-5g/L nickel nitrate, 1-4g/L zinc dihydrogen phosphate, 1-5mL/L phosphoric acid, 1-3g/L citric acid, 0.5-1.5g/L potassium pyrophosphate, 0.5-1.5mL/L OP-10 emulsifier, 0.04-0.07g/L graphene oxide and water.

3. The steel normal temperature blackening agent of claim 2, wherein the steel normal temperature blackening agent comprises the following components: 3-5g/L selenious acid, 2-3g/L copper sulfate, 1-2g/L nickel nitrate, 3g/L zinc dihydrogen phosphate, 2-3mL/L phosphoric acid, 2g/L citric acid, 1g/L potassium pyrophosphate, 1mL/L OP-10 emulsifier, 0.04-0.07g/L graphene oxide and water.

4. The steel normal temperature blackening agent of claim 3, wherein the steel normal temperature blackening agent comprises the following components: 3g/L selenious acid, 2g/L copper sulfate, 1g/L nickel nitrate, 3g/L zinc dihydrogen phosphate, 2mL/L phosphoric acid, 2g/L citric acid, 1g/L potassium pyrophosphate, 1mL/L OP-10 emulsifier, 0.04-0.07g/L graphene oxide and water; preferably, the content of the graphene oxide is 0.05-0.06 g/L; more preferably, the graphene oxide is 0.05 g/L.

5. an ambient steel blackening agent according to any of claims 1 to 4, which is characterized in that: the pH of the blackening agent is between 1.5 and 2.5.

6. The preparation method of the steel normal temperature blackening agent is characterized in that the components of the steel normal temperature blackening agent according to any one of claims 1 to 5 are uniformly mixed until the components are completely dissolved to obtain the steel normal temperature blackening agent.

7. A method for blackening an iron and steel room temperature blackening agent according to any one of claims 1 to 5, characterized in that: and (3) immersing the steel sample into a steel normal-temperature blackening agent to completely blacken the surface of the sample to form a uniform film, immediately taking out the sample, staying the sample in the air for 1-3min, and cleaning the sample to obtain the blackened steel sample.

8. A blackening method of an ordinary-temperature steel blackening agent according to claim 7, characterized in that: immersing the steel sample in a steel normal-temperature blackening agent for 10-14min and then taking out; preferably, the steel sample is taken out after being immersed in the steel normal temperature blackening agent for 10 min.

9. A blackening method of an ordinary-temperature steel blackening agent according to claim 7, characterized in that: immersing a steel sample into a steel normal-temperature blackening agent with the temperature of 25-30 ℃; preferably, the steel sample is immersed in the steel room temperature blackening agent at a temperature of 25 ℃.

10. A blackening method of an ordinary-temperature steel blackening agent according to claim 7, characterized in that: before the steel is blackened, pretreatment is required; the pretreatment method comprises the following steps: polishing, deoiling and derusting the steel sample, then activating the steel sample by adopting 5-10 wt.% of sulfuric acid, and finally cleaning the steel sample; after the steel is blackened, post-treatment is needed, and the method comprises the following steps: dehydrating the blackened steel sample; preferably, the dewatering treatment uses dewatering cotton to remove water from the sample after blackening.

Technical Field

The invention relates to a normal-temperature steel blackening agent, a preparation method and a blackening method thereof, belonging to the technical field of corrosion protection of metal materials.

Background

The steel is an indispensable material in the rapid development of the current society and is seen everywhere in our life, and the yield and the usage amount of the steel are standards for measuring the economic level of each country. However, steel has a major disadvantage, and according to statistics, due to corrosion loss of steel materials and protection cost of the materials, about 3% -5% of the total production value of China per year is lost, about 30% of steel products are scrapped due to corrosion every year in the world, and although most of the steel products can be recycled, 10% of steel products are still lost. Therefore, researchers in various countries around the world are still striving to find more effective steel surface preservation measures.

Fe as a main component of steel, which is easily mixed with O in the air₂、H₂O, etc. react to form corrosion, causing corrosion that eventually results in irreparable losses. This is unavoidable for the current environment, so in order to improve the corrosion resistance of steel in service, scientists all over the world are still trying to explore new methods for corrosion protection of steel. In the aspect of steel corrosion prevention, a method for blackening steel is often adopted, and the blackening process has the advantages of convenient preparation of a blackening agent, short blackening treatment period and good cost performance.

At present, the normal temperature blackening agent is divided into a selenium-containing blackening agent and a selenium-free blackening agent, the selenium-containing blackening agent is divided into a selenium-copper system, a selenium-copper-phosphorus system and the like, the selenium-copper system is the most successful system in the current normal temperature blackening of steel, the blackening effect of the selenium-copper system is better than that of other systems, but the corrosion resistance of the system is still to be improved. Zhou hong is in research on blackening at normal temperature of steel (Master academic paper, Shandong university, 2009) a kind of blackening agent at normal temperature of steel is disclosed. The prepared blackening agent comprises the following components: 2-5g/L selenious acid, 1-4g/L copper sulfate, 1-3g/L nickel nitrate, 2-5g/L zinc dihydrogen phosphate, 2-4mL/L phosphoric acid, 1-2g/L citric acid, 1-3mL/L OP-10 emulsifier and 0.02-0.08g/L brightener. However, when the blackening agent is used for blackening steel, the treated material has poor corrosion resistance.

Disclosure of Invention

The invention aims to solve the first technical problem of providing a steel normal temperature blackening agent with better corrosion resistance.

The steel normal-temperature blackening agent takes water as a solvent and comprises the following components: 1-5g/L selenious acid, 1-5g/L copper sulfate, 1-5g/L nickel nitrate, 1-4g/L zinc dihydrogen phosphate, 1-5mL/L phosphoric acid, 1-3g/L citric acid, 0.5-1.5g/L potassium pyrophosphate, 0.5-1.5mL/L OP-10 emulsifier and 0.04-0.07g/L graphene oxide.

Preferably, the steel normal temperature blackening agent consists of the following components: 1-5g/L selenious acid, 1-5g/L copper sulfate, 1-5g/L nickel nitrate, 1-4g/L zinc dihydrogen phosphate, 1-5mL/L phosphoric acid, 1-3g/L citric acid, 0.5-1.5g/L potassium pyrophosphate, 0.5-1.5mL/L OP-10 emulsifier, 0.04-0.07g/L graphene oxide and water.

More preferably, the steel normal temperature blackening agent consists of the following components: 3-5g/L selenious acid, 2-3g/L copper sulfate, 1-2g/L nickel nitrate, 3g/L zinc dihydrogen phosphate, 2-3mL/L phosphoric acid, 2g/L citric acid, 1g/L potassium pyrophosphate, 1mL/L OP-10 emulsifier, 0.04-0.07g/L graphene oxide and water.

Further preferably, the steel normal temperature blackening agent comprises the following components: 3g/L selenious acid, 2g/L copper sulfate, 1g/L nickel nitrate, 3g/L zinc dihydrogen phosphate, 2mL/L phosphoric acid, 2g/L citric acid, 1g/L potassium pyrophosphate, 1mL/L OP-10 emulsifier, 0.04-0.07g/L graphene oxide and water;

More preferably, the graphene oxide is 0.05-0.06 g/L; more preferably, the graphene oxide is 0.05 g/L.

Preferably, the pH of the blackening agent is between 1.5 and 2.5.

The second technical problem to be solved by the invention is to provide a preparation method of the steel normal temperature blackening agent.

The preparation method of the steel normal temperature blackening agent comprises the steps of uniformly mixing the components of the steel normal temperature blackening agent until the components are completely dissolved, thus obtaining the steel normal temperature blackening agent.

The invention also provides a method for blackening by adopting the steel blackening agent.

The blackening method of the normal-temperature steel blackening agent comprises the following steps: and (3) immersing the steel sample into a steel normal-temperature blackening agent to completely blacken the surface of the sample to form a uniform film, immediately taking out the sample, staying the sample in the air for 1-3min, and cleaning the sample to obtain the blackened steel sample.

Preferably, the steel sample is immersed in the steel normal temperature blackening agent for 10-14min and then taken out.

More preferably, the steel sample is immersed in the steel room temperature blackening agent for 10min and then taken out.

Preferably, the steel sample is immersed in a steel normal temperature blackening agent with the temperature of 25-30 ℃; more preferably, the steel sample is immersed in the steel room temperature blackening agent at a temperature of 25 ℃.

Preferably, the steel needs to be pretreated before blackening; the pretreatment method comprises the following steps: polishing, degreasing and derusting the steel sample, activating the steel sample by adopting 5-10 wt% of sulfuric acid, and finally cleaning the steel sample; after the steel is blackened, post-treatment is needed, and the method comprises the following steps: dehydrating the blackened steel sample; preferably, the dewatering treatment uses dewatering cotton to remove water from the sample after blackening.

The invention has the beneficial effects that:

1. Compared with the blackening agent without the graphene oxide, the black steel has better adhesive force, corrosion resistance and wear resistance by adding the graphene oxide.

2. The blackening agent provided by the invention enables the surface of steel to have good performances similar to those of graphene, such as better conductivity, reduction of stress in steel workpieces, more uniform and attractive blackening, increase of antifriction and wear resistance of the surface of steel, and the like.

Drawings

FIG. 1 is a flow chart of a process of a blackening experiment of a graphene oxide blackening agent;

FIG. 2 is a graph showing the comparison between the appearance of a blackened product prepared by using different amounts of graphene oxide (0.01g/L, 0.03g/L, 0.05g/L, 0.1g/L) and a sample (labeled "none") which is not blackened and is only subjected to pretreatment;

Fig. 3 is a gold phase diagram (100 ×) of a blackening sample with or without addition of graphene oxide, wherein (a) is a blackening film layer without addition of graphene oxide, and (b) is a blackening film layer with addition of graphene oxide;

Fig. 4 is a gold phase diagram (200 ×) of a blackening sample with or without addition of graphene oxide, wherein (a) shows a blackening film layer without addition of graphene oxide, and (b) shows a blackening film layer with addition of graphene oxide;

Fig. 5 is an SEM image (500 ×) of a blackening sample with or without addition of graphene oxide, in which (a) is SEM observation of a blackening film layer without addition of graphene oxide, and (b) is SEM observation of a blackening film layer with addition of graphene oxide;

Fig. 6 is an SEM image (1000 ×) of a blackening sample with or without addition of graphene oxide, in which (a) is SEM observation of a blackening film layer without addition of graphene oxide, and (b) is SEM observation of a blackening film layer with addition of graphene oxide;

FIG. 7 is a film cross-sectional energy spectrum analysis, wherein (a) is a black film cross-sectional morphology and line scan analysis, wherein (b) is a C element distribution, wherein (C) is a Se element distribution, wherein (d) is a Cu element distribution, wherein (e) is a P element distribution, and wherein (f) is an O element distribution;

FIG. 8 is an X-ray diffraction pattern, wherein (a) no graphene oxide is added, (b) the addition amount of graphene oxide is 0.05g/L, and (c) the addition amount of graphene oxide is 0.1 g/L;

Fig. 9 is a polarization curve of samples with different amounts of graphene oxide added.

Detailed Description

The invention aims to solve the first technical problem of providing a steel normal temperature blackening agent with better corrosion resistance.

The steel normal-temperature blackening agent takes water as a solvent and comprises the following components: 1-5g/L selenious acid, 1-5g/L copper sulfate, 1-5g/L nickel nitrate, 1-4g/L zinc dihydrogen phosphate, 1-5mL/L phosphoric acid, 1-3g/L citric acid, 0.5-1.5g/L potassium pyrophosphate, 0.5-1.5mL/L OP-10 emulsifier and 0.04-0.07g/L graphene oxide.

The selenium-copper system is blackened at normal temperature, the blackened film layer mainly comprises CuSe, the secondary component mainly comprises phosphate, and the CuSe is mainly formed through oxidation-reduction reaction. According to the invention, the adhesion, corrosion resistance and wear resistance of steel blackening at normal temperature are improved by adding multiple layers of graphene oxide.

According to the invention, the content of the graphene oxide is limited to 0.04-0.07g/L, and when the content is not in the range, the corrosion resistance of the obtained film layer is poor.

In order to improve the film performance of the blackened steel surface, preferably, the steel normal temperature blackening agent comprises the following components: 1-5g/L selenious acid, 1-5g/L copper sulfate, 1-5g/L nickel nitrate, 1-4g/L zinc dihydrogen phosphate, 1-5mL/L phosphoric acid, 1-3g/L citric acid, 0.5-1.5g/L potassium pyrophosphate, 0.5-1.5mL/L OP-10 emulsifier, 0.04-0.07g/L graphene oxide and water.

More preferably, the steel normal temperature blackening agent consists of the following components: 3-5g/L selenious acid, 2-3g/L copper sulfate, 1-2g/L nickel nitrate, 3g/L zinc dihydrogen phosphate, 2-3mL/L phosphoric acid, 2g/L citric acid, 1g/L potassium pyrophosphate, 1mL/L OP-10 emulsifier, 0.04-0.07g/L graphene oxide and water.

Further preferably, the steel normal temperature blackening agent comprises the following components: 3g/L selenious acid, 2g/L copper sulfate, 1g/L nickel nitrate, 3g/L zinc dihydrogen phosphate, 2mL/L phosphoric acid, 2g/L citric acid, 1g/L potassium pyrophosphate, 1mL/L OP-10 emulsifier, 0.04-0.07g/L graphene oxide and water;

in order to further improve the film performance of the blackened steel surface, more preferably, the graphene oxide is 0.05-0.06 g/L; more preferably, the graphene oxide is 0.05 g/L.

Preferably, the pH of the blackening agent is between 1.5 and 2.5.

During the test, it was found that the pH value seriously affects the performance of the black coating layer. When the pH value is too high, the film forming speed is slow, even the film can not be blackened, the film thickness is different even after the film is formed, the color is reduced, the binding force is poor, and precipitates are easy to generate for the blackened liquid, so that the solution is unstable; when the pH value is lower, the surface of the substrate can generate hydrogen evolution corrosion and can not be phosphated and blackened, so that the bonding force of the film layer is poorer, and the film layer performance is influenced by the phenomena of floating, ash floating and the like generated on the surface. Tests have shown that the membrane layer performs best when the pH is between 1.5 and 2.5.

The second technical problem to be solved by the invention is to provide a preparation method of the steel normal temperature blackening agent.

The preparation method of the steel normal temperature blackening agent comprises the steps of uniformly mixing the components of the steel normal temperature blackening agent until the components are completely dissolved, thus obtaining the steel normal temperature blackening agent.

The invention also provides a method for blackening by adopting the steel blackening agent.

The blackening method of the normal-temperature steel blackening agent comprises the following steps: and (3) immersing the steel sample into a steel normal-temperature blackening agent to completely blacken the surface of the sample to form a uniform film, immediately taking out the sample, staying the sample in the air for 1-3min, and cleaning the sample to obtain the blackened steel sample. During the blackening process, the solution can be stirred by using the sample, so that the effective components in the blackening solution are fully contacted and reacted with the surface of the sample substrate.

The steel blocks forming the uniform film layer are taken out and are allowed to stay in the air for 1-3min, so that the film layer continuously reacts with residual liquid under the action of oxygen in the air, and then the film layer is cleaned by using absorbent cotton to lightly wipe the film layer, so that the surface of the film layer is not filled with water and residual liquid, and the phenomenon that the film layer is poor in color and luster and uneven due to the influence of the water can be avoided.

Preferably, the steel sample is immersed in the steel normal temperature blackening agent for 10-14min and then taken out.

More preferably, the steel sample is immersed in the steel room temperature blackening agent for 10min and then taken out.

Preferably, the steel sample is immersed in a steel normal temperature blackening agent with the temperature of 25-30 ℃; more preferably, the steel sample is immersed in the steel room temperature blackening agent at a temperature of 25 ℃.

Preferably, the steel needs to be pretreated before blackening; the pretreatment method comprises the following steps: polishing, degreasing and derusting the steel sample, activating the steel sample by adopting 5-10 wt% of sulfuric acid, and finally cleaning the steel sample; after the steel is blackened, post-treatment is needed, and the method comprises the following steps: dehydrating the blackened steel sample; preferably, the dewatering treatment uses dewatering cotton to remove water from the sample after blackening.

The steel sample is subjected to a blackening pretreatment before being subjected to blackening, and plays a very important role in the quality of a film obtained after the blackening. The pretreatment before blackening in the test mainly comprises four steps: polishing, deoiling, derusting, activating and cleaning.

Firstly, grinding

In the test, the surface of the metal substrate was carefully sanded with sandpaper until it was 1500 #.

② oil removal

This test uses lye to remove oil to clean the metal surface. After the oil removing step is completed, the sample needs to be washed by water so as to achieve the purpose that the surface of the sample is free from alkali liquor. The formulation and technological parameters of the oil-removing alkali liquor are shown in the table 0-1.

Alkaline degreasing formula and process parameters of samples in table 0-1

Thirdly, rust removal

and the rust removal adopts acid cleaning. The formula and technological parameters of the acid rust removing liquid are shown in the table 0-2.

TABLE 0-2 acidic derusting formulation and technological parameters for iron and steel

Activation

The test uses 9% sulfuric acid (H)₂SO₄) Activating treatment is carried out, and the technological parameters are as follows: room temperature, time: 1-1.5 min.

cleaning

The test adopts the process of flowing water cleaning and deionized water ultrasonic cleaning instrument cleaning.

The blackened steel sample needs to be post-treated. Because the film layer is in a porous net structure after blackening, residual liquid and water can be remained, and therefore, a sample needs to be dehydrated after blackening and cleaning, and dehydrated cotton is adopted to discharge water. Thus, the corrosion resistance of the film layer can be obviously improved, and the appearance color and luster and the attractiveness of the film layer can be improved.

The following examples are provided to further illustrate the embodiments of the present invention and are not intended to limit the scope of the present invention. The following examples and comparative examples used identical steel workpieces: q235 cold-rolled strip steel (10 mm. times.50 mm. times.3 mm). Before blackening, the Q235 cold-rolled strip steel sheets are subjected to blackening pretreatment, and the blackening pretreatment processes are completely the same.

The following examples, comparative examples and examples were subjected to corrosion resistance tests in a specific manner: wiping the blackened sample with a cotton ball dipped with ethanol, and then using a rubber dropper to remove 3% CuSO₄The corrosion resistance was evaluated by dropping a drop of the solution on the surface of the specimen and observing and recording the time of the earliest brick red color.