ERT sensor electrode and preparation method and application thereof

Abstract

The invention discloses an ERT sensor electrode and a preparation method and application thereof.The ERT sensor electrode comprises a stainless steel substrate and a copper reinforcement body, blind holes covering the side surface of the stainless steel substrate are evenly distributed in one side of the stainless steel substrate, and blind hole reinforcement parts matched with the blind holes in the surface of the stainless steel substrate are evenly distributed on the copper reinforcement body; the blind hole and the blind hole reinforcing piece are tightly embedded to form a stainless steel-copper composite layer; according to the ERT sensor electrode, the stainless steel serves as the substrate, the copper reinforcement is introduced, the conductivity of the ERT sensor electrode is remarkably improved while the abrasion resistance and corrosion resistance of the electrode are guaranteed, the blind holes in the stainless steel substrate and the blind hole reinforcement pieces matched with the blind holes in the copper reinforcement are tightly embedded, and the corrosion resistance of the electrode is greatly improved. The firm combination of the stainless steel substrate and the copper reinforcement is ensured, and the conductivity of the electrode is further enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of fluid measurement, and in particular relates to an ERT sensor electrode and a preparation method and application thereof. Background Art

[0002] The ERT concentration meter consists of pipeline sensors, signal acquisition and processing hardware modules, and host computer imaging and concentration calculation software. The principle of electrical resistance tomography is to use the resistivity difference inside an object to create an image. When current passes through an object, the resistivity of different materials is different, so the current propagation speed inside the object is also different; by measuring the current propagation speed inside the object, the resistivity distribution inside the object can be inferred, and then the internal structure of the object can be reconstructed.

[0003] The structural parameters of the ERT sensor will affect the soft field characteristics of the sensitive field, making the sensor voltage response signal unstable. Therefore, the structural parameter design of the ERT sensor has an important impact on the performance of the ERT system. At present, there are many studies on electrode arrays, which can be improved and enhanced in terms of the number of electrodes (such as 8, 12, 16), electrode shape (such as rectangle, circle), and electrode arrangement (such as single circle point electrode, multi-circle point electrode, single circle rectangular electrode, multi-circle rectangular electrode).

[0004] However, there is almost no research on electrode materials in China. The performance of ERT electrode materials is mainly reflected in two aspects: (1) The wear resistance, corrosion resistance and conductivity of the material affect the imaging accuracy of the electrode. When the material is washed by sediment particles, it will be worn and scratched. At this time, the defects on the electrode surface will cause the loss of imaging accuracy, and the material with poor conductivity will affect the imaging accuracy by affecting the current transfer. (2) The wear resistance and corrosion resistance of the material will directly affect the service life of the electrode.

[0005] At present, most of the applications of ERT electrode materials are basically focused on wear resistance and corrosion resistance. Since the strength of the material itself is mostly enhanced by increasing the defects between crystals, and these defects will cause the metal conductivity to deteriorate, even if you want to increase the conductivity, you must consider whether it will affect its wear resistance and corrosion resistance. Currently, ERT electrodes are mostly made of stainless steel and Hastelloy, which have poor conductivity, so the imaging accuracy will be greatly affected and reduced; therefore, how to improve the conductivity of electrode materials while maintaining corrosion resistance and wear resistance is a problem that needs to be solved urgently. Summary of the invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide an ERT sensor electrode and its preparation method and application, which can greatly enhance its conductivity without affecting the wear resistance and corrosion resistance of the electrode itself, thereby improving the imaging accuracy of the ERT sensor.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The first aspect of the present invention is to provide an ERT sensor electrode, comprising a stainless steel substrate and a copper reinforcement, wherein blind holes covering the side surface are evenly distributed on one side of the stainless steel substrate, and blind hole reinforcements matching the blind holes on the surface of the stainless steel substrate are evenly distributed on the copper reinforcement, and the blind holes and the blind hole reinforcements are tightly embedded to form a stainless steel-copper composite layer.

[0009] A second aspect of the present invention is to provide a method for preparing an ERT sensor electrode, comprising the following steps:

[0010] S1. Laser drilling: A blind hole that evenly covers the entire main surface is processed on one main surface of the stainless steel electrode by laser;

[0011] S2. Ultrasonic pre-immersion: The stainless steel electrode with blind holes is washed with oil and water and then placed in an ultrasonic pre-immersion solution for ultrasonic treatment;

[0012] S3. Insulation protection: Insulate the non-electroplating parts of the stainless steel electrode after ultrasonic treatment;

[0013] S4. Hole-filling electroplating: Under room temperature, the stainless steel electrode with good insulation protection is immersed in the electroplating solution, the stainless steel electrode is used as the cathode plated part, and the phosphor copper ball is used as the anode for direct current electroplating. The electroplating process is continuously stirred until all the blind holes on the stainless steel electrode are filled with copper, thereby obtaining a stainless steel-copper composite material;

[0014] S5. Electroplating copper layer: Replace the new electroplating solution, increase the current density and continue the DC electroplating until a 1.5-2 mm copper layer is electroplated on the surface of the stainless steel electroplating-copper composite material, then stop the electroplating and take out the plated part;

[0015] S6. Polishing and cleaning: The plated component obtained in step S5 is first sonicated with pure water for 30 minutes, then sonicated with anhydrous ethanol for 30 minutes, and then dried at room temperature; the dried plated component is polished to make the electrode surface smooth. After polishing, the surface is rinsed with pure water for five minutes, and then dried at room temperature to obtain the ERT sensor electrode.

[0016] Furthermore, the laser in step S1 is a laser suitable for drilling millimeter-level holes in stainless steel, and the beam focusing power of the laser drilling is 10 5 ~106 W / mm 2 .

[0017] Furthermore, in step S1, for a stainless steel electrode having a thickness of 0.1 to 0.5 cm, the depth of the processed blind hole is 0.05 to 0.1 cm.

[0018] The blind hole depth of 0.05 cm to 0.1 cm is conducive to electroplating and can ensure that the blind hole on the stainless steel electrode is filled with electroplated copper.

[0019] Furthermore, in step S2, the ultrasonic pre-immersion liquid is a mixed solution of sodium dodecyl sulfate and sodium poly(dipropylene glycol disulfide) sulfonate, wherein the concentration of sodium dodecyl sulfate is 10-20 mg / L, and the concentration of sodium poly(dipropylene glycol disulfide) sulfonate is 1.5-2 mg / L.

[0020] The use of this ultrasonic pre-dip liquid to ultrasonically pre-dip the stainless steel electrode can drive away the bubbles in the blind hole, improve the wetting of the inner wall and bottom of the blind hole, and by pre-filling the accelerator molecules, the copper in the blind hole can be quickly deposited in the subsequent hole filling electroplating process, thereby enhancing the electroplating filling effect.

[0021] Furthermore, the conditions of the ultrasonic treatment in step S2 are: power 220W-240W, frequency 35KHz-40KHz, and ultrasonic treatment time 1min-2min.

[0022] Furthermore, the electroplating solution ratio in steps S3 and S4 is: 280-320 g / L copper sulfate pentahydrate, 65-75 g / L sulfuric acid, 75-85 mg / L sodium chloride, 10-20 mg / L inhibitor, 1-2 mg / L accelerator, and 25-30 mg / L leveler.

[0023] Furthermore, the inhibitor is polyethylene glycol or polypropylene glycol, the accelerator is sodium polydisulfide propane sulfonate or sodium 3-mercapto-1-propane sulfonate, and the leveler is sodium sulfate.

[0024] Furthermore, the current density of the DC electroplating in step S4 is 1 to 2 A / dm 2 The current density of the DC plating in step S5 is 4 to 6 A / dm 2 .

[0025] When the hole filling electroplating is performed in step S4, the current density is 1 to 2 A / dm 2 , which can ensure the electroplating efficiency and prevent voids from appearing during the electroplating hole filling process; increasing the current density when electroplating the copper layer in step S5 can improve the electroplating efficiency.

[0026] A third aspect of the present invention is to provide an application of an ERT sensor electrode in ERT measurement technology, wherein the ERT sensor electrode is the above-mentioned ERT sensor electrode or is prepared by the above-mentioned ERT sensor electrode preparation method.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects:

[0028] The ERT sensor electrode provided by the present invention uses stainless steel as a substrate and introduces a copper reinforcement, which significantly improves the conductivity of the ERT sensor electrode. The blind holes on the stainless steel substrate are tightly fitted with the blind hole reinforcement pieces on the copper reinforcement that match the blind holes, ensuring a firm bond between the stainless steel substrate and the copper reinforcement, further enhancing the conductivity of the electrode. In practical applications, since the stainless steel outer layer is in direct contact with the fluid, and the internal conductivity is mainly Cu, this not only meets the requirements of corrosion resistance and wear resistance, but also greatly improves the conductivity of the electrode.

[0029] The ERT sensor electrode preparation method provided by the present invention performs laser drilling on a stainless steel substrate and fills the holes on the stainless steel substrate by direct current electroplating, thereby greatly enhancing the conductivity of the electrode while ensuring the wear resistance and corrosion resistance of the electrode; compared with plating a protective layer on the surface of a copper electrode, directly drilling holes on the stainless steel substrate and electroplating copper filling can not only increase the contact area between the copper layer and the stainless steel substrate, making the combination of the two closer and enhancing the conductivity of the electrode, but also solves the problem of insufficient plating thickness and poor bonding force on the surface of the stainless steel substrate; in practical applications, since the stainless steel outer layer is in direct contact with the fluid, and the internal conductivity is mainly Cu, this not only meets the requirements of corrosion resistance and wear resistance, but also greatly improves the conductivity of the electrode.

[0030] The ERT sensor electrode prepared by the preparation method of the ERT sensor electrode provided by the present invention has a conductivity nearly 2.5 times higher than that of the existing stainless steel electrode, thereby improving the imaging accuracy of the ERT sensor. The method of the present invention has the advantages of simple operation, high controllability and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic structural diagram of the ERT sensor electrode of the present invention;

[0032] Figure 2 It is a structural schematic diagram of the stainless steel substrate of the present invention;

[0033] Figure 3 It is a schematic diagram of the structure of the copper reinforcement of the present invention;

[0034] In the figure: 1- stainless steel substrate; 11- blind hole;

[0035] 2-copper reinforcement; 21-blind hole reinforcement;

[0036] 3- Stainless steel-copper composite layer. DETAILED DESCRIPTION

[0037] The present invention will be further described below by specific embodiments in conjunction with the accompanying drawings. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0038] It should be noted that the "main surface" in the present invention refers to the surface with the largest area among all surfaces of the stainless steel electrode, the oil washing liquid used for oil washing is an acidic oil washing liquid for stainless steel, and ultrapure water is used for water washing; the components of the phosphor copper ball in the present invention include, by mass percentage: 99.5% to 99.9% Cu, 0.03% to 0.5% P, and a small amount of impurities Fe and S.

[0039] Example 1

[0040] The preparation method of the ERT sensor electrode of this embodiment includes the following steps:

[0041] S1. Laser drilling: Use Nd:YAG laser to uniformly drill holes on one main surface of a 1cm*1cm*0.3cm stainless steel electrode. Use pulsed laser with a beam focusing power of 10 5 W / mm 2 , a total of 25 blind holes with a diameter of 0.1 cm and a depth of 0.1 cm were machined on the main surface;

[0042] S2. Ultrasonic pre-immersion: The stainless steel electrode with holes was washed with oil and water, and then placed in an ultrasonic pre-immersion solution (10 mg / L sodium dodecyl sulfate + 1.5 mg / L sodium polydisulfide propane sulfonate) at an ultrasonic power of 240 W and an ultrasonic frequency of 40 kHz for 1 min.

[0043] S3. Insulation protection: Insulation glue is applied to the non-electroplating parts of the stainless steel electrode after ultrasonic treatment;

[0044] S4. Hole filling electroplating: At room temperature, immerse the stainless steel electrode with insulating glue into 1L of electroplating solution (300g / L copper sulfate pentahydrate + 70g / L sulfuric acid + 80mg / L sodium chloride + 10mg / L polyethylene glycol + 2mg / L sodium polydisulfide propane sulfonate + 30mg / L sodium sulfate). Use the stainless steel electrode as the cathode and the phosphor copper ball as the anode. The current density is 2A / dm 2 , direct current electroplating was performed, stirring was continued during the electroplating process, and after 7 hours of electroplating, all the blind holes on the stainless steel electrode were filled with copper to obtain a stainless steel-copper composite material;

[0045] S5. Electroplating copper layer: Replace the new electroplating solution with the same proportion and increase the current density to 6A / dm 2 , continue direct current electroplating, after electroplating for 5 hours, a 2 mm copper layer is electroplated on the surface of the stainless steel electroplating-copper composite material, stop electroplating, and take out the plated part;

[0046] S6. Polishing and cleaning: The plated component obtained in step S5 is first sonicated with pure water for 30 minutes, then sonicated with anhydrous ethanol for 30 minutes, and then dried at room temperature; the dried plated component is polished to make the electrode surface smooth. After polishing, the surface is rinsed with pure water for five minutes, and then dried at room temperature to obtain an ERT sensor electrode, recorded as X1.

[0047] The overall resistivity of X1 at room temperature was measured by the Van der Pauw method to be 0.32*10 -6 Ω·m.

[0048] Example 2

[0049] Compared with Example 1, the ratio of the electroplating solution in this example is changed to: 280 g / L copper sulfate pentahydrate, 65 g / L sulfuric acid, 75 mg / L sodium chloride, 10 mg / L polyethylene glycol, 1 mg / L sodium polydisulfide dipropane sulfonate, and 25 mg / L sodium sulfate;

[0050] The ERT sensor electrode is obtained and is recorded as X2.

[0051] The overall resistivity of X2 at room temperature was measured by the Van der Pauw method to be 0.34*10 -6 Ω·m.

[0052] Example 3

[0053] Compared with Example 1, the ratio of the electroplating solution in this example is changed to: 320 g / L copper sulfate pentahydrate, 75 g / L sulfuric acid, 85 mg / L sodium chloride, 10 mg / L polyethylene glycol, 1 mg / L sodium polydisulfide dipropane sulfonate, and 30 mg / L sodium sulfate;

[0054] The ERT sensor electrode is obtained and is recorded as X3.

[0055] The overall resistivity of X3 at room temperature was measured by the Van der Pauw method to be 0.32*10 -6 Ω·m.

[0056] Example 4

[0057] Compared with Example 1, the ratio of the electroplating solution in this example is changed to: 320 g / L copper sulfate pentahydrate, 75 g / L sulfuric acid, 85 mg / L sodium chloride, 10 mg / L polypropylene glycol, 1 mg / L sodium 3-mercapto-1-propanesulfonate, and 30 mg / L sodium sulfate;

[0058] The ERT sensor electrode is obtained and is recorded as X4.

[0059] The overall resistivity of X4 at room temperature was measured by the Van der Pauw method to be 0.33*10 -6 Ω·m.

[0060] Example 5

[0061] Compared with Example 1, in this embodiment, the diameter of the blind hole processed in the laser drilling in step S1 is changed to 0.2 cm, and the depth is changed to 0.05 cm;

[0062] The ERT sensor electrode is obtained and is recorded as X5.

[0063] The overall resistivity of X5 at room temperature was measured by the Van der Pauw method to be 0.52*10 -6 Ω·m.

[0064] Example 6

[0065] Compared with Example 1, the current density of the direct current plating in step S4 of the hole filling electroplating is changed to 1A / dm 2 , the current density of direct current electroplating in step S5 copper electroplating layer is changed to 4A / dm 2 ;

[0066] The ERT sensor electrode is obtained and is recorded as X6.

[0067] The overall resistivity of X6 at room temperature was measured by the Van der Pauw method to be 0.32*10 -6 Ω·m.

[0068] Example 7

[0069] Compared with Example 1, in this example, the Nd:YAG laser in the laser drilling in step S1 is replaced by a fiber laser, the ratio of the ultrasonic pre-immersion liquid in step S2 is changed to: 20 mg / L sodium dodecyl sulfate, 2 mg / L sodium polydisulfide propane sulfonate, and the ultrasonic treatment conditions are changed to: power 220 W, frequency 35 KHz, and ultrasonic treatment for 2 min.

[0070] The ERT sensor electrode is obtained and is recorded as X7.

[0071] The overall resistivity of X7 at room temperature was measured by the Van der Pauw method to be 0.32*10 -6 Ω·m.

[0072] Comparative Example 1

[0073] At present, the electrode material commonly used in ERT sensors is SS316 stainless steel. The resistivity of SS316 stainless steel at room temperature is measured by the Van der Pauw method to be 0.73*10 -6Ω·m, the conductivity of the ERT sensor electrodes prepared in Examples 1 to 7 of the present invention is nearly 2.5 times higher than that of the electrode material.

[0074] Comparative Example 2

[0075] At present, the electrode material commonly used in ERT sensors is Hastelloy C276. The resistivity of Hastelloy C276 at room temperature is measured by the Van der Pauw method to be 1.24*10 -6 Ω·m, the conductivity of the ERT sensor electrodes prepared in Examples 1 to 7 of the present invention is nearly 4 times higher than that of the electrode material.

[0076] Therefore, by comparing the resistivity of the above-mentioned Examples 1 to 7 and Comparative Examples 1 to 2 at room temperature, it can be known that the conductivity of the ERT sensor electrode prepared by the method of the present invention is at least 2.5 times higher than that of the conventional ERT sensor electrode.

[0077] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An ERT sensor electrode, characterized in that: The invention comprises a stainless steel substrate and a copper reinforcement. Blind holes covering the side surface are evenly distributed on one side of the stainless steel substrate. Blind hole reinforcements matching the blind holes on the surface of the stainless steel substrate are evenly distributed on the copper reinforcement. The blind holes and the blind hole reinforcements are tightly embedded to form a stainless steel-copper composite layer.

2. A method for preparing an ERT sensor electrode, characterized in that: The following steps are involved: S1. Laser drilling: A blind hole that evenly covers the entire main surface is processed on one main surface of the stainless steel electrode by laser; S2. Ultrasonic pre-immersion: The stainless steel electrode with blind holes is washed with oil and water and then placed in an ultrasonic pre-immersion solution for ultrasonic treatment; S3. Insulation protection: Insulate the non-electroplating parts of the stainless steel electrode after ultrasonic treatment; S4. Hole-filling electroplating: Under room temperature, the stainless steel electrode with good insulation protection is immersed in the electroplating solution, the stainless steel electrode is used as the cathode plated part, and the phosphor copper ball is used as the anode for direct current electroplating. The electroplating process is continuously stirred until all the blind holes on the stainless steel electrode are filled with copper, thereby obtaining a stainless steel-copper composite material; S5. Electroplating copper layer: Replace the new electroplating solution, increase the current density and continue the DC electroplating until a 1.5-2 mm copper layer is electroplated on the surface of the stainless steel electroplating-copper composite material, then stop the electroplating and take out the plated part; S6. Polishing and cleaning: The plated component obtained in step S5 is first sonicated with pure water for 30 minutes, then sonicated with anhydrous ethanol for 30 minutes, and then dried at room temperature; the dried plated component is polished to make the electrode surface smooth. After polishing, the surface is rinsed with pure water for five minutes, and then dried at room temperature to obtain the ERT sensor electrode.

3. The method for preparing the ERT sensor electrode according to claim 2, characterized in that: The laser in step S1 is a laser suitable for drilling millimeter-level holes in stainless steel, and the beam focusing power of the laser drilling is 10 5 ~10 6 W / mm 2 .

4. The method for preparing the ERT sensor electrode according to claim 2, characterized in that: In the step S1, for a stainless steel electrode with a thickness of 0.1 to 0.5 cm, the depth of the processed blind hole is 0.05 to 0.1 cm.

5. The method for preparing the ERT sensor electrode according to claim 2, characterized in that: In step S2, the ultrasonic pre-immersion liquid is a mixed solution of sodium dodecyl sulfate and sodium poly(dipropylene glycol disulfide) sulfonate, wherein the concentration of sodium dodecyl sulfate is 10-20 mg / L, and the concentration of sodium poly(dipropylene glycol disulfide) sulfonate is 1.5-2 mg / L.

6. The method for preparing the ERT sensor electrode according to claim 2, characterized in that: The conditions of the ultrasonic treatment in step S2 are: power 220W-240W, frequency 35KHz-40KHz, and ultrasonic treatment for 1min-2min.

7. The method for preparing the ERT sensor electrode according to claim 2, characterized in that: The electroplating solution ratio in steps S4 and S5 is: 280-320 g / L of copper sulfate pentahydrate, 65-75 g / L of sulfuric acid, 75-85 mg / L of sodium chloride, 10-20 mg / L of inhibitor, 1-2 mg / L of accelerator, and 25-30 mg / L of leveler.

8. The method for preparing the ERT sensor electrode according to claim 7, characterized in that: The inhibitor is polyethylene glycol or polypropylene glycol, the accelerator is sodium polydisulfide propane sulfonate or sodium 3-mercapto-1-propane sulfonate, and the leveler is sodium sulfate.

9. The method for preparing the ERT sensor electrode according to claim 2, characterized in that: The current density of the DC electroplating in step S4 is 1-2A / dm 2 The current density of the DC plating in step S5 is 4 to 6 A / dm 2 .

10. An application of an ERT sensor electrode in ERT measurement technology, characterized in that: The ERT sensor electrode is the ERT sensor electrode according to claim 1 or is prepared by the preparation method according to any one of claims 1-9.

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