阅读说明：本技术 一种用于铝合金的脉冲电流阴极保护方法 (Pulse current cathodic protection method for aluminum alloy ) 是由 李国明 迟钧瀚 周冬 于 2021-09-10 设计创作，主要内容包括：本发明公开了一种用于铝合金的脉冲电流阴极保护方法,在占空比和周期不变的情况下,随着幅值从-1.05V负移到-1.3V,初始极化电位与放电末端电位都发生负移,但两电位之差基本保持不变,在幅值和脉冲极化时间不变的条件下,随着占空比从1:1减小到1:20,放电末端电位逐渐发生正移,且极化初始电位和放电末端电位之差逐渐增大,占空比对试样电位的影响主要体现在延长了空置时间,幅值,占空比恒定的条件下,随着周期从210ms增大到1260ms,试样的放电末端电位先逐渐增大,而后基本保持不变,极化初始电位和放电末端电位之差先增大后保持基本稳定,但当周期继续大幅增大时,也会随之增大。(The invention discloses a pulse current cathodic protection method for aluminum alloy, under the condition of unchanging duty ratio and period, with the amplitude value negatively shifted from-1.05V to-1.3V, the initial polarization potential and the discharge end potential are both negatively shifted, but the difference between the two potentials Basically, the voltage of the discharge end gradually moves forward and the difference between the polarization initial voltage and the voltage of the discharge end gradually shifts as the duty ratio is reduced from 1:1 to 1:20 under the condition of unchanged amplitude and pulse polarization time The gradual increase is carried out, the influence of the duty ratio on the sample potential is mainly embodied in that the discharge tail end potential of the sample is gradually increased and then basically kept unchanged along with the increase of the period from 210ms to 1260ms under the conditions of prolonging the idle time, the amplitude and the constant duty ratio, the polarization initial potential and the discharge tail end potential are chargedDifference of bits Increase and then remain substantially stable, but as the cycle continues to increase substantially,)

1. A pulsed current cathodic protection method for aluminum alloys is characterized by comprising the following operating steps:

s1: the existing CS350 electrochemical workstation is modified into a special pulse power supply, a low-delay ADG1401 high-frequency electronic switch with the opening and closing time of 240ns is added into the original potentiostat circuit by analyzing the pulse principle, and a polarization time sequence function is added into control software to control the duty ratio and the period parameter when the pulse is output, so that a stable pulse potential/current waveform with adjustable parameters is obtained;

s2: the method researches the cathodic protection process of pulse potential by adopting a controlled variable methodThe influence of amplitude, duty ratio and period on the potential of a 5083 aluminum alloy sample, and the potential of the sample is at the pulse initial polarization potential in the pulse potential protection processAnd discharge end potentialChange in between withThe amplitude increases (-1.05V to-1.3V),negative shift, but change in potential valueTends to be stable, and the potential-time curve is stable under the condition of each parameter along with the reduction of the duty ratio (1: 1-1: 20)Are all moving forward, butGradually increasing; as the period increases (210ms to 1260ms),a negative shift, but not a large change value,the stability is approached, and the influence of the amplitude and the duty ratio on the pulse cathodic protection process is larger than the period;

s3: the influence of amplitude, duty ratio and period on the potential of a 5083 aluminum alloy sample in the process of pulse current cathodic protection is researched by adopting a controlled variable method, the potential of the sample is gradually changed and is negative in the process of pulse current cathodic protection, and finally, the potential of the sample is initially and gradually changed and is negativePolarization potentialAnd discharge end potentialThe current I1 is increased in amplitude (-10 muA to-60 muA),andall are shifted negatively, but the potential change valueTends to be stable, and as the duty ratio is reduced (1: 1-1: 20),andare all moving forward, butAlso increased, as with the pulsed potential protection process, period<1200ms) has a relatively small influence on the sample potential.

2. The pulsed current cathodic protection method for aluminum alloys as claimed in claim 1 wherein said 5083 aluminum alloy is treated and prepared prior to use, the treatment materials comprising: epoxy resin, dimethyl phthalate, ethylenediamine, U-PVC (polyvinyl chloride) tubes, absolute ethyl alcohol, acetone, water grinding abrasive paper, polishing paste, an ultrasonic cleaner and a drying dish, and the processing steps are as follows:

k1: cutting;

k2: cleaning;

k3: welding;

k4: packaging;

k5: polishing;

k6: and (6) polishing.

3. The method of claim 2, wherein 5083 aluminum alloy is cut into warp threads and tapped for connecting to a lead wire at a non-test surface, all samples are 10mm x 8mm in size, and the test surface area is 1cm²。

4. The pulsed current cathodic protection method for aluminum alloy as claimed in claim 2, wherein the surface impurities of the 5083 aluminum alloy after being cut by warp is brushed by a soft hair toothbrush, and then ultrasonic cleaning is carried out for 15min by using acetone and an ultrasonic cleaner.

5. The method as claimed in claim 2, wherein the cleaned aluminum alloy sample is soldered with solder in the tapped hole by using pure copper wire.

6. The method for pulsed current cathodic protection of aluminum alloy according to claim 2, wherein a U-PVC pipe is used as a mold, epoxy resin is used to encapsulate 5083 aluminum alloy, the epoxy resin material is prepared from 80 wt.% of epoxy resin, 15 wt.% of dimethyl phthalate and 5 wt.% of ethylenediamine, and the encapsulation is cured for 48 hours before use.

7. The method for pulsed current cathodic protection of aluminum alloys according to claim 2, wherein the packaged 5083 aluminum alloy working surface is ground with water abrasive paper, which is ground with 400 mesh, 800 mesh, 1200 mesh, 2000 mesh in sequence.

8. The pulsed current cathodic protection method for aluminum alloys of claim 2, wherein the dressed 5083 aluminum alloy is used as a cathode protection material for aluminum alloysGold was mechanically polished with a paste of W1.5 Al₂O₃After polishing, acetone is used for removing oil, absolute ethyl alcohol is used for cleaning and then drying, and 5083 aluminum alloy is placed in a drying dish for 24 hours for standby after polishing and cleaning.

Technical Field

The invention relates to the technical field of pulse current cathodic protection, in particular to a pulse current cathodic protection method for aluminum alloy.

Background

The 21 st century is the oceanic century and oceanic economy is becoming a new and high place for the development of global economy. The ocean has abundant fish resources and mineral resources, is an area for disputed development of various countries and is an important place for national security defense. China has a proposition administration sea area of more than 300 ten thousand square kilometers and a coastline exceeding 18000 kilometers, and is a genuine oceanic kingdom.

Referring to offshore construction, ships constructed of steel materials and offshore work platforms are naturally suggested. Steel is widely used in the manufacture of ships and large offshore platforms as a metal material which is well developed. The steel material has many excellent properties, such as high strength, good forgeability, etc. However, in the case of a harsh marine environment, the corrosion resistance of steel is greatly examined. According to incomplete statistics, the direct loss caused by marine corrosion in China is more than 5000 billion yuan each year, and the corrosion not only can cause the non-countercurrent loss of metal materials, but also can bring great potential safety hazards to marine development and construction. Therefore, when a ship is manufactured by using a metal material and an ocean platform is built, the corrosion resistance of the material and the effectiveness of protective measures are very important.

Compared with steel materials, the aluminum alloy has the advantages of lower density, higher specific strength, better processing performance and better heat conductivity and electric conductivity. But most importantly, the aluminum alloy is more resistant to seawater corrosion. Therefore, the use of aluminum alloys is becoming more and more widespread in the shipbuilding industry. As early as 1892, aluminum alloys have been used to manufacture ships. The aluminum alloy has obvious advantages in shipbuilding due to low density and good processing performance: the ship body has light weight, fast sailing speed and strong maneuverability, can increase the load, and carries more equipment and fuel. Therefore, the method is very suitable for manufacturing small and medium-sized ships. Due to the excellent corrosion resistance, the aluminum alloy ship can reduce the maintenance cost and reduce the energy consumption compared with a steel ship. The aluminum alloy ship has the advantages that the aluminum alloy ship does not need to be demagnetized regularly, can avoid the attack of a magnetic mine and improve the accuracy of instruments for ships of military, and can continuously ensure the normal use of various instruments and equipment.

China began to use Al-Cu series aluminum alloy to build speedboats in the last century, but the Al-Cu series alloy has poor corrosion resistance in a seawater environment, so the aluminum alloy for building naval boats is gradually replaced by Al-Mg series alloy, such as 5083 aluminum alloy. The 5083 aluminum alloy is an antirust aluminum, and has good corrosion resistance, welding performance and mechanical performance.

The marine environment is the most complex, most abundant and highly corrosive natural electrolyte environment in nature. Therefore, even 5083 rust-proof aluminum having a good corrosion resistance has a corrosion problem in the ocean.

Aluminum alloy is mainly subject to pitting corrosion in seawater environment, and 5083 aluminum alloy is no exception. Generally speaking, the local corrosion of aluminum alloy in atmospheric environment is not serious, however, in seawater environment, pitting pits can develop deeply under the action of aggressive Cl < - >, and even lead to aluminum alloy perforation seriously, which brings great harm to ships and warships sailing on the ocean. In the cathodic protection technology, aluminum is often used as a sacrificial anode because of its high electronegativity. However, for the existing aluminum alloy vessels, the aluminum alloy is generally protected by the traditional impressed current cathodic protection method, or the aluminum alloy is protected by a coating like most steel vessels, or the two methods are combined. For metal structures with complex structures and huge volumes, such as naval vessels, the traditional external direct current cathodic protection generally needs larger current to protect the ship body, so that the protection potentials at the far end and the near end are not uniform. This protection method with large applied current brings about two problems: (1) aluminum belongs to amphoteric metal, the protective current is too small, and aluminum alloy can generate pitting corrosion; the protection current is too large, the aluminum alloy can generate hydrogen evolution to cause alkaline corrosion, and the two conditions can cause the damage of the ship body. (2) The excessive applied current results in high energy consumption, and is not the best method from the economic point of view. If the coating technology is used for protection, if the coating at the damaged part is not repaired in time, the pitting corrosion characteristic of the aluminum alloy in seawater is further amplified, and the pitting corrosion pit is rapidly deepened.

Therefore, a technology capable of realizing characteristics of long protection distance, uniform protection potential distribution, low energy consumption and the like is needed to protect the aluminum alloy, and the dilemma of aluminum alloy protection in the current seawater environment is solved.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a pulse current cathode protection method for aluminum alloy, which has the advantages of seawater corrosion prevention and the like and solves the problem that the aluminum alloy is corroded by seawater.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: a pulsed current cathodic protection process for aluminum alloys comprising the following operative steps:

s1: the existing CS350 electrochemical workstation is modified into a special pulse power supply, a pulse principle is analyzed, a low-delay ADG1401 high-frequency electronic switch with the opening and closing time of 240ns is added into an original potentiostat circuit, a polarization time sequence function is added into control software to control the space ratio and the period parameter during pulse output, and a stable pulse potential/current waveform with adjustable parameters is obtained;

s2: the influence of amplitude, duty ratio and period on the potential of a 5083 aluminum alloy sample in the pulse potential cathodic protection process is researched by adopting a controlled variable method, and the sample potential in the pulse potential protection process is at the pulse initial polarization potentialAnd discharge end potentialChange in between withThe amplitude increases (-1.05V to-1.3V),negative shift, but change in potential valueTends to be stable, and the potential-time curve is stable under the condition of each parameter along with the reduction of the duty ratio (1: 1-1: 20)Are all moving forward, butGradually increasing; as the period increases (210ms to 1260ms),a negative shift, but not a large change value,the stability is approached, and the influence of the amplitude and the duty ratio on the pulse cathodic protection process is larger than the period;

s3: the influence of amplitude, duty ratio and period on the potential of a 5083 aluminum alloy sample in the process of pulse current cathodic protection is researched by a controlled variable method, the potential of the sample in the process of pulse current cathodic protection is gradually changed to be negative, and finally the initial polarization potential isAnd discharge end potentialThe current I1 is increased in amplitude (-10 muA to-60 muA),andall are shifted negatively, but the potential change valueTends to be stable, and as the duty ratio is reduced (1: 1-1: 20),andare all moving forward, butAlso increased, as with the pulsed potential protection process, period<1200ms) has a relatively small influence on the sample potential.

Preferably, the 5083 aluminum alloy is treated and prepared prior to use, the treated materials comprising: epoxy resin, dimethyl phthalate, ethylenediamine, U-PVC (polyvinyl chloride) tubes, absolute ethyl alcohol, acetone, water-milled sand paper, polishing paste, an ultrasonic cleaner and a drying dish, and the processing steps are as follows:

k1: cutting;

k2: cleaning;

k3: welding;

k4: packaging;

k5: polishing;

k6: and (6) polishing.

Preferably, the 5083 aluminum alloy is cut into warp threads, and is tapped on a non-test surface for connecting a wire, all samples are 10mm multiplied by 8mm, and the area of the test surface is 1cm²。

Preferably, the surface impurities of the 5083 aluminum alloy after the warp cutting are firstly brushed by a soft-hair toothbrush, and then the ultrasonic cleaning is carried out for 15min by using acetone and an ultrasonic cleaner.

The aluminum alloy sample after cleaning is preferably soldered in the tapped hole with a solder using a pure copper wire.

Preferably, a U-PVC pipe is used as a mold, 5083 aluminum alloy is packaged by epoxy resin, the epoxy resin comprises 80 wt% of epoxy resin, 15 wt% of dimethyl phthalate and 5 wt% of ethylenediamine, and the epoxy resin is packaged and cured for 48 hours for later use.

Preferably, the packaged 5083 aluminum alloy working surface is polished by using water-mill abrasive paper, and the water-mill abrasive paper is polished by 400 meshes, 800 meshes, 1200 meshes and 2000 meshes in sequence.

Preferably, the polished 5083 aluminum alloy is mechanically polished with W1.5 Al₂O₃After polishing, acetone is used for removing oil, absolute ethyl alcohol is used for cleaning and then drying, and 5083 aluminum alloy is placed in a drying dish for 24 hours for later use after being polished and cleaned.

(III) advantageous effects

Compared with the prior art, the invention provides a pulse current cathodic protection method for aluminum alloy, which has the following beneficial effects:

1. the pulse current cathodic protection method for the aluminum alloy is characterized in that the initial polarization potential and the discharge end potential are both negatively shifted with the amplitude being negatively shifted from-1.05V to-1.3V under the condition of constant duty ratio and period, but the difference between the two potentials isBasically, the voltage of the discharge end gradually moves forward as the duty ratio is reduced from 1:1 to 1:20 under the condition of unchanged amplitude and pulse polarization time, and the difference between the polarization initial voltage and the discharge end voltageThe effect of the duty ratio on the sample potential is mainly reflected in the prolongation of the idle time.

2. The pulse current cathodic protection method for the aluminum alloy comprises the steps that under the conditions of constant amplitude and constant duty ratio, as the period is increased from 210ms to 1260ms, the discharge end potential of a sample is gradually increased and then basically kept unchanged, and the difference between the polarization initial potential and the discharge end potentialRemains substantially stable after increasing, but as the cycle continues to increase substantially,and will also increase.

The specific implementation mode is as follows:

a pulsed current cathodic protection method for aluminum alloys comprises the following operating steps:

s1: the existing CS350 electrochemical workstation is modified into a special pulse power supply, a pulse principle is analyzed, a low-delay ADG1401 high-frequency electronic switch with the opening and closing time of 240ns is added into an original potentiostat circuit, a polarization time sequence function is added into control software to control the space ratio and the period parameter during pulse output, and a stable pulse potential/current waveform with adjustable parameters is obtained;

s2: the influence of amplitude, duty ratio and period on the potential of a 5083 aluminum alloy sample in the pulse potential cathodic protection process is researched by adopting a controlled variable method, and the sample potential in the pulse potential protection process is at the pulse initial polarization potentialAnd discharge end potentialChange in between withThe amplitude increases (-1.05V to-1.3V),negative shift, but change in potential valueTends to be stable, and the potential-time curve is stable under the condition of each parameter along with the reduction of the duty ratio (1: 1-1: 20)Are all moving forward, butGradually increasing; as the period increases (210ms to 1260ms),negative shiftBut the variation value is not large,the stability is approached, and the influence of the amplitude and the duty ratio on the pulse cathodic protection process is larger than the period;

s3: the influence of amplitude, duty ratio and period on the potential of a 5083 aluminum alloy sample in the process of pulse current cathodic protection is researched by a controlled variable method, the potential of the sample in the process of pulse current cathodic protection is gradually changed to be negative, and finally the initial polarization potential isAnd discharge end potentialThe current I1 is increased in amplitude (-10 muA to-60 muA),andall are shifted negatively, but the potential change valueTends to be stable, and as the duty ratio is reduced (1: 1-1: 20),andare all moving forward, butAlso increased, as with the pulsed potential protection process, period<1200ms) has less influence on the potential of the sample, and the 5083 aluminum alloy needs to be treated and prepared before being used, and the treatment materials comprise: epoxy resin, dimethyl phthalate, ethylenediamine, U-PVC (polyvinyl chloride) pipe, absolute ethyl alcohol, acetone, water abrasive paper, polishing paste and ultrasonic cleanerAnd a drying dish, and the processing steps are as follows:

k1: cutting;

k2: cleaning;

k3: welding;

k4: packaging;

k5: polishing;

k6: and (6) polishing.

5083 aluminum alloy is obtained by cutting warp, tapping on non-test surface for connecting wires, and making all samples 10mm × 10mm × 8mm in size and test surface area 1cm²Surface impurities of 5083 aluminum alloy subjected to warp cutting are brushed by a soft-bristle toothbrush, then the aluminum alloy is subjected to ultrasonic cleaning for 15min by using acetone and an ultrasonic cleaner, a cleaned aluminum alloy sample is welded in a tapped hole by using a pure copper wire by using soldering tin, a U-PVC pipe is used as a mold, epoxy resin encapsulates the 5083 aluminum alloy, the epoxy resin comprises 80 wt% of epoxy resin, 15 wt% of dimethyl phthalate and 5 wt% of ethylenediamine, the aluminum alloy is used for standby after encapsulation and solidification for 48 hours, a 5083 aluminum alloy working surface after encapsulation is polished by using water abrasive paper, the water abrasive paper polishes 400 meshes, 800 meshes, 1200 meshes and 2000 meshes in sequence, 5083 aluminum alloy after polishing is subjected to mechanical polishing, and polishing paste is W1.5 Al₂O₃After polishing, acetone is used for removing oil, absolute ethyl alcohol is used for cleaning and then drying, and 5083 aluminum alloy is placed in a drying dish for 24 hours for standby after polishing and cleaning.