Precious metal oxide coating titanium anode with high salt, high humidity and long service life

Abstract

The utility model discloses a high-salt high-humidity long-life precious metal oxide coating titanium anode which comprises a titanium base material, an intermediate layer metal platinum and a precious metal oxide coating, and the precious metal oxide coating is an iridium tantalum oxide coating. The metal platinum is added between the anode substrate and the iridium tantalum oxide coating, so that the anode has good current efficiency and lower oxygen evolution potential in a high-salt and high-humidity soil environment, the service life of the anode is obviously prolonged, the comprehensive performance of the anode is obviously improved, and the service life of the anode is prolonged. The device is suitable for a buried pipeline and a storage tank impressed current cathode protection anode ground bed and the like in a high-salt and high-humidity soil environment.

Description

Technical Field

[0001] This utility model relates to the field of electrochemistry, specifically to a high-salt, high-humidity, long-life noble metal oxide coated titanium anode. Background Technology

[0002] Hybrid metal oxide anodes are made by coating a titanium substrate (ASTM B 265 Grade 1 titanium) with a layer of electrocatalytically active metal oxides (oxides of metals such as ruthenium, iridium, and titanium). This coating can improve the conductivity of the anode. By adjusting the composition of the oxide layer, it can be adapted to different environments, such as seawater, freshwater, and soil media. Hybrid metal oxide tubular anodes have advantages such as light weight, good conductivity, high cost-effectiveness, and strong corrosion resistance, making them the most promising auxiliary anode material to replace high-silicon cast iron anodes in cathodic protection. However, traditional hybrid metal oxide anodes often face the problem of voltage decay during use. When the soil resistivity is low or the corrosion protection layer of the protected structure is in poor condition, the anode voltage will gradually decrease, leading to a decline in protection effectiveness. Especially in the case of low soil resistivity, the anode consumption rate near the energization point is accelerated, which may lead to premature anode failure, requiring replacement and increasing maintenance costs and difficulty. In addition, the hybrid metal oxide anode coating also has chemical and electrochemical stability issues during long-term use.

[0003] Therefore, in the field of cathodic protection, there is a need for a mixed metal oxide anode for cathodic protection that is suitable for various soil environments, especially high-salt and high-moisture soil environments, can be used for a long time, and has stable chemical and electrochemical properties. Utility Model Content

[0004] The purpose of this invention is to provide a high-salt, high-humidity, long-life noble metal oxide coated titanium anode to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a high-salt, high-humidity, long-life noble metal oxide coated titanium anode, comprising a titanium substrate, an intermediate layer of platinum metal, and a noble metal oxide coating; wherein the noble metal oxide coating is an iridium-tantalum oxide coating.

[0006] Preferably, the titanium substrate surface is coated with an intermediate layer of platinum metal, and the intermediate layer of platinum metal is coated with a noble metal oxide coating.

[0007] Preferably, the thickness of the intermediate platinum metal layer is 1 μm.

[0008] Preferably, the iridium-tantalum oxide coating comprises iridium dioxide and tantalum pentoxide in a molar ratio of 70:30.

[0009] Preferably, the iridium tantalum oxide coating loading reaches 3 g / m².

[0010] Preferably, the titanium substrate is a tubular TA2 industrial pure titanium tube with a diameter of Φ25*1000mm.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] (1) By adding platinum metal between the anode substrate and the iridium tantalum oxide coating, the anode has good current efficiency, low oxygen evolution potential, and significantly extended service life in high-salt and high-humidity soil environments. It significantly improves the overall performance of the anode and is suitable for impressed current cathodic protection anode beds for buried pipelines and storage tanks in high-salt and high-humidity soil environments. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the noble metal oxide coated titanium anode with an intermediate layer according to the present invention.

[0014] In the figure: 1-Titanium substrate, 2-Intermediate layer platinum metal, 3-Noble metal oxide coating. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0016] Please see Figure 1 A high-salt, high-humidity, long-life noble metal oxide coated titanium anode includes a titanium substrate 1, an intermediate platinum metal 2, and a noble metal oxide coating 3; the noble metal oxide coating 3 is an iridium-tantalum oxide coating.

[0017] The surface of the titanium substrate 1 is coated with an intermediate layer of platinum metal 2, and the surface of the intermediate layer of platinum metal 2 is coated with a noble metal oxide coating 3.

[0018] By adding platinum metal between the anode substrate and the iridium tantalum oxide coating, the anode exhibits good current efficiency, low oxygen evolution potential, and significantly extended service life in high-salt and high-humidity soil environments, thus significantly improving the overall performance of the anode. It is suitable for impressed current cathodic protection anode beds for buried pipelines and storage tanks in high-salt and high-humidity soil environments.

[0019] The thickness of the intermediate platinum layer 2 is 1µm. This 1µm thickness ensures sufficient bonding strength and conductivity while avoiding the increased cost and processing difficulty that might result from an excessively thick intermediate layer. This thickness choice leads to a more compact overall structure and superior performance.

[0020] The iridium-tantalum oxide coating comprises iridium dioxide and tantalum pentoxide in a molar ratio of 70:30; the iridium-tantalum oxide coating loading reaches 3 g / m².

[0021] Iridium-tantalum oxide coatings exhibit excellent corrosion resistance and electrocatalytic activity, making them a leader among noble metal oxide coatings. Iridium dioxide (IrO2) possesses extremely high corrosion resistance, while tantalum pentoxide (Ta2O5) helps improve the stability and electrocatalytic performance of the coating. By combining iridium dioxide and tantalum pentoxide in a molar ratio of 70:30, a coating with balanced performance and excellent overall characteristics can be obtained.

[0022] The titanium substrate 1 is a tubular Φ25*1000mm TA2 industrial pure titanium tube.

[0023] Example 1

[0024] A high-salt, high-humidity, long-life noble metal oxide coated titanium anode includes a titanium substrate 1, an intermediate platinum layer 2, and a noble metal oxide coating 3; the noble metal oxide coating 3 is an iridium-tantalum oxide coating.

[0025] Step (1) Substrate pretreatment: A tubular Φ25*1000mm TA2 industrial pure titanium tube is used as the electrode substrate. First, the titanium tube is sandblasted with diamond abrasive with a particle size of 120um. The residual sand particles and metal shavings are removed by rinsing with distilled water. Then, the titanium tube is placed in acetone for degreasing. After degreasing, it is soaked in 20% NaOH solution for 30min, and then soaked in 20% H2SO4 solution for 30min. Finally, the titanium tube is placed in 25% oxalic acid solution and kept at boiling for 1-1.5h. After removal, it is ultrasonically cleaned in deionized water for 10min to obtain the pretreated tubular titanium metal body.

[0026] Step (2) Prepare the intermediate layer metal platinum coating solution: Add chloroplatinic acid to n-butanol solvent, stir magnetically for 0.5 h, adjust the solvent to make the molar concentration of platinum ions in the solution 0.3 mol / L, and the volume of the coating solution is 10 mL.

[0027] Step (3) Prepare the mixed metal oxide coating solution: Add chloroiridic acid and tantalum oxide to n-butanol solvent at a molar ratio of 70:30, and the concentration of the coating solution is 0.3 mol / L.

[0028] Step (4) Coating and sintering: The coating solution prepared in step (2) is brushed onto the pretreated titanium tube. First, it is dried in an oven at 120°C for 15 minutes, then sintered in a sintering furnace at 600°C for 15 minutes. After that, it is taken out and air-cooled. The coating, drying, sintering and cooling steps are repeated until the Pt thickness on the surface of the titanium tube substrate reaches 1 μm. Finally, it is sintered in a muffle furnace at 600°C for 1.5 hours and placed in a drying furnace for later use.

[0029] After the spare parts are cooled, the coating solution prepared in step (3) is brushed onto the titanium tube. First, it is dried in an oven at 120°C for 15 minutes, and then sintered in a sintering furnace at 600°C for 15 minutes. After that, it is taken out and air-cooled. The coating, drying, sintering and cooling steps are repeated until the metal oxide loading on the surface of the titanium tube substrate reaches 3 g / m². Finally, it is sintered in a muffle furnace at 600°C for 1.5 h to obtain a mixed metal oxide anode with a platinum-containing intermediate layer.

[0030] Comparative Example 1

[0031] A titanium anode with a noble metal oxide coating includes a titanium substrate and an iridium-tantalum oxide coating.

[0032] The difference between this comparative example and Example 1 is that no intermediate layer of platinum is added, and the Ir:Ta molar ratio is 75:25.

[0033] The preparation method is the same as in Example 1.

[0034] Comparative Example 2

[0035] A titanium anode with a noble metal oxide coating includes a titanium substrate and an iridium-tantalum oxide coating.

[0036] The difference between this comparative example and Example 1 is that no intermediate layer of platinum is added.

[0037] The preparation method is the same as in Example 1.

[0038] Comparative Example 3

[0039] A titanium anode with a noble metal oxide coating includes a titanium substrate and an iridium-tantalum oxide coating.

[0040] The difference between this comparative example and Example 1 is that no intermediate layer of platinum is added, and the Ir:Ta molar ratio is 65:35.

[0041] The preparation method is the same as in Example 1.

[0042] Enhanced lifespan testing

[0043] The titanium anodes with noble metal oxide coatings used in each comparative example and Example 1 were used as test samples. The cathodes were 2.5 mm × 200 mm pure titanium sheets with an electrode spacing of 20 mm. The anode potential was measured using the three-electrode method, with a 232-type saturated calomel electrode as the reference electrode. At room temperature, the electrolyte solution was 1 mol / L Na₂SO₄, and the current density was 20000 A / m. 2 Enhanced life tests were conducted, and a 4V rise in tank voltage or anode potential was used as the basis for judging anode failure. The results of the enhanced life test of mixed metal oxide anodes are shown in Table 1.

[0044] Table 1

[0045]

[0046] As can be seen, compared with traditional mixed metal oxide anodes used in soil environments, the mixed metal oxide anodes of the present invention exhibit superior electrochemical performance and stability. Compared with the enhanced lifespan of Comparative Examples 1-3, the enhanced electrolytic lifespan of the anodes of the present invention is longer, indicating that the stability of the anode is significantly improved by adding Pt to the surface of the titanium tube substrate, resulting in superior stability and lifespan in high-salt soil environments.

[0047] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-salt, high-humidity, long-life noble metal oxide coated titanium anode, characterized in that, Includes a titanium substrate, an intermediate layer of platinum metal, and a coating of noble metal oxides; The noble metal oxide coating is an iridium-tantalum oxide coating; The thickness of the intermediate platinum metal layer is 1 μm.

2. The high-salt, high-humidity, long-life noble metal oxide coated titanium anode as described in claim 1, characterized in that, The titanium substrate is coated with an intermediate layer of platinum, and the surface of the intermediate platinum is coated with a noble metal oxide coating.

3. The high-salt, high-humidity, long-life noble metal oxide coated titanium anode as described in claim 1, characterized in that, The iridium tantalum oxide coating has a loading of 3 g / m².

4. The high-salt, high-humidity, long-life noble metal oxide coated titanium anode as described in claim 1, characterized in that, The titanium substrate is a tubular 25*1000mm TA2 industrial pure titanium tube.

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