Coating material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of energy materials, and discloses a coating material as well as a preparation method and application thereof. The coating material comprises the following components in parts by weight: 50-55 parts of zirconium oxide, 15-18 parts of aluminum oxide, 5.5-9 parts of rare earth oxide, 10-12 parts of a fluorocarbon polymer and 3-4 parts of a silane coupling agent, the rare earth oxide comprises yttrium oxide and cerium oxide. A natural gas hydrogen-doped pipeline coating prepared from the coating material has low permeability, high adhesive force, high hardness and excellent stability, can effectively inhibit hydrogen atoms from gathering and diffusing in the material in high-temperature, high-pressure, hydrogen-doped and other complex environments, has excellent hydrogen embrittlement resistance and good chemical stability and mechanical property, and can be used for preparing the natural gas hydrogen-doped pipeline coating. The pipeline failure risk caused by hydrogen embrittlement can be remarkably reduced, the performance degradation phenomena such as aging and decomposition are not prone to occurring, and long-term stable operation of the pipeline can be guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of energy materials, and in particular to a coating material, a preparation method thereof, and an application thereof. Background Art

[0002] As the global energy mix shifts toward a low-carbon economy, natural gas hydrogen-blended pipelines have garnered widespread attention due to their environmental advantages. However, due to the high permeability and strong reducing properties of hydrogen, natural gas hydrogen-blended pipelines face severe hydrogen embrittlement during gas transmission. These pipelines are susceptible to aging, microcracks, and leaks, threatening operational safety. Furthermore, as the hydrogen blending ratio increases, the durability of natural gas hydrogen-blended pipelines also decreases significantly. For example, when the hydrogen blending ratio exceeds 15%, the fatigue crack growth rate of the pipe increases by 2-3 times. When the hydrogen blending ratio reaches 30%, the pipe's hydrogen embrittlement susceptibility index increases by 40% compared to a pure hydrogen environment. This material degradation not only causes microcracks to initiate and propagate, but can also lead to pipeline seal failure, becoming a key issue hindering the large-scale application of hydrogen blending technology.

[0003] Existing anti-hydrogen embrittlement coatings are mainly divided into two major systems: metal-based and ceramic-based. However, both have significant performance shortcomings under the working conditions of natural gas hydrogen-blended pipelines. Metal coatings are usually thermally sprayed or electroplated, and can form a porous structure under high temperature (>800°C). Although they can maintain a low permeability in a pure hydrogen environment, in a hydrogen-blended natural gas mixture containing CO2 and H2S, the grain boundary corrosion of the coating can easily lead to a surge in permeability. For example, in a 10ppmH2S+5%CO2 environment, a FeS / FeCO3 mixed corrosion product film is generated on the inner wall of the pores of the metal coating, and its loose porous structure causes the hydrogen permeability to surge to 10 -8 cm 2 / s. At the same time, the interfacial bonding strength between the metal coating and the substrate is also difficult to withstand pipeline pressure fluctuations. For example, the brittle oxide transition layer formed between the NiCrAlY coating and the X70 steel substrate will undergo microcrack expansion under a pressure fluctuation of 0.5MPa, and the interface peeling rate will reach 18% within one year of service. Although ceramic coatings such as alumina coatings have a hardness of 1300HV, their intrinsic brittleness makes them prone to through-cracks during cold bending of pipelines. The hydrogen concentration at the crack tip can reach 5.7 times that of the substrate, significantly accelerating the process of hydrogen embrittlement. At the same time, the residual stress generated during the processing of the ceramic coating makes the actual adhesion of the coating only 8MPa, and delamination failure is very likely to occur under a working pressure of 20MPa.

[0004] Furthermore, existing hydrogen-embrittlement-resistant coatings struggle to balance barrier performance with mechanical reliability. In complex corrosive media (e.g., H2S / CO2 / H2O coexistence), they are prone to synergistic degradation and exacerbated hydrogen lattice diffusion, severely impacting the safe serviceability of natural gas hydrogen-blended pipelines under high-pressure, long-term operating conditions. Therefore, there is an urgent need to develop a new composite coating material that can achieve a synergistic improvement in hydrogen barrier performance and interface reliability to meet the demand for high-performance natural gas hydrogen-blended pipeline coatings in the energy transportation sector. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a coating material and a preparation method and application thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a coating material comprising the following components in parts by weight: 50-55 parts of zirconium oxide, 15-18 parts of aluminum oxide, 5.5-9 parts of rare earth oxide, 10-12 parts of fluorocarbon polymer and 3-4 parts of silane coupling agent; the rare earth oxide comprises yttrium oxide and cerium oxide.

[0008] The coating material obtained by compounding zirconium oxide, aluminum oxide, rare earth oxides, fluorocarbon polymers and silane coupling agents in the present invention achieves multi-dimensional synergistic optimization of chemical stability, mechanical properties and interface reliability. It has low permeability, high adhesion, high hardness and excellent stability, providing a high-performance protection solution for natural gas hydrogen-blended transmission pipelines. Among them, firstly, zirconium oxide, as the main phase of the material, has a dense crystal structure that can effectively block the penetration of small molecules such as hydrogen, and cooperates with other components to give the material excellent chemical stability and low permeability. Secondly, aluminum oxide is evenly dispersed in the zirconium oxide matrix, filling the microscopic defects within the material, enhancing the material's density and structural integrity, and cooperating with other components to improve the material's hardness and wear resistance. At the same time, rare earth oxides, on the one hand, act as stabilizers, can effectively inhibit the phase transformation of zirconium oxide, and cooperate with other components to enhance the high-temperature stability of the material, ensuring that the coating can still maintain good performance in a high-temperature hydrogen-blended natural gas environment; on the other hand, rare earth oxides can optimize the matrix lattice structure, reduce the diffusion path of hydrogen within the material, and further improve the material's resistance to hydrogen permeation. In addition, the presence of fluorocarbon polymer and silane coupling agent further synergistically improves the interfacial bonding strength of the material, improves the adhesion performance of the material, and helps to evenly disperse the external stress throughout the material system, further improving the mechanical properties and reliability of the material.

[0009] As a preferred embodiment of the coating material of the present invention, the mass ratio of the yttrium oxide to the cerium oxide is (8-10):1.

[0010] As a preferred embodiment of the coating material of the present invention, the fluorocarbon polymer includes at least one of polytetrafluoroethylene, polyvinylidene fluoride and polyperfluoroethylene propylene.

[0011] As a preferred embodiment of the coating material of the present invention, the silane coupling agent includes at least one of γ-aminopropyltriethoxysilane (KH-550), γ-glycidoxypropyltrimethoxysilane (KH-560) and γ-methacryloxypropyltrimethoxysilane (KH-570).

[0012] As a preferred embodiment of the coating material of the present invention, the particle size of the aluminum oxide is 50 nm-100 nm; the particle size of the fluorocarbon polymer is 50 nm-100 nm.

[0013] In a second aspect, the present invention provides a method for preparing the coating material, comprising the following steps:

[0014] (1) mixing the zirconium oxide, aluminum oxide, and rare earth oxide, and grinding them to obtain a mixture;

[0015] (2) adding the fluorocarbon polymer and the silane coupling agent to the mixture and performing ultrasonic dispersion to obtain the coating material.

[0016] In a third aspect, the present invention provides a natural gas hydrogen-blended pipeline coating, wherein the natural gas hydrogen-blended pipeline coating is made of the coating material.

[0017] In a fourth aspect, the present invention provides a method for preparing the natural gas hydrogen-doped pipeline coating, comprising the following steps: spraying the coating material onto a substrate, heat treating, and polishing to obtain the natural gas hydrogen-doped pipeline coating.

[0018] As a preferred embodiment of the method for preparing the natural gas hydrogen-blended pipeline coating of the present invention, the spraying adopts a pulse plasma spraying method; the frequency of the pulse plasma spraying is 100Hz-200Hz, the current is 450A-550A, and the spraying distance is 90mm-110mm; the heat treatment adopts a graded heat treatment method; the graded heat treatment is carried out in the following stages: (1) the first stage: the temperature is 500℃-700℃, and the time is 0.5h-2h; (2) the second stage: the temperature is 800℃-1000℃, and the time is 0.5h-2h.

[0019] In a fifth aspect, the present invention provides applications of the coating material and the natural gas hydrogen-blended pipeline coating in the field of energy transportation.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: First, the coating material obtained by compounding multiple components of the present invention realizes multi-dimensional coordinated optimization of chemical stability-mechanical properties-interface reliability, has low permeability, high adhesion, high hardness and excellent stability, and can still maintain good chemical stability and mechanical properties in complex environments such as high temperature, high pressure, and hydrogen doping. It is not easy to experience performance degradation phenomena such as aging and decomposition, and can ensure the long-term stable operation of the pipeline. At the same time, the natural gas hydrogen-blended pipeline coating prepared by the coating material of the present invention can effectively inhibit the aggregation and diffusion of hydrogen atoms inside the material in a hydrogen-blended natural gas composite environment, has excellent resistance to hydrogen embrittlement, and can significantly reduce the risk of pipeline failure caused by hydrogen embrittlement. In addition, the preparation method of the coating material and the natural gas hydrogen-blended pipeline coating of the present invention has mild conditions, simple preparation steps, low preparation energy consumption, can achieve a dynamic balance between particle melting and solidification, and is easy to repeat and quantitatively produce. DETAILED DESCRIPTION

[0021] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] The following is an elaboration with reference to specific embodiments to illustrate the practical effects of the present invention.

[0023] Unless otherwise specified, the experimental methods used in the examples are conventional methods; the materials, reagents, equipment, etc. used are all available from commercial sources unless otherwise specified.

[0024] Example 1: Preparation of natural gas hydrogen-blended pipeline coating

[0025] The raw materials for preparing the natural gas hydrogen-blended pipeline coating of this embodiment include the following components in parts by weight: 50 parts of zirconium oxide (ZrO2), 5 parts of yttrium oxide (Y2O3), 15 parts of nano-alumina (Al2O3, particle size 80nm), 10 parts of nano-grade polytetrafluoroethylene (PTFE, particle size 70nm), 3 parts of silane coupling agent (KH-550), and 0.5 parts of cerium oxide (CeO2).

[0026] (1) ZrO2, Y2O3, Al2O3 and CeO2 were weighed according to their weight and mixed, and then ground using a planetary ball mill (ethanol medium, ball-to-material ratio of 1:2, 300 rpm, 4 hours).

[0027] (2) KH-550 and nano-PTFE were added to the mixed powder after ball milling, and ultrasonic dispersion (40 kHz, 30 minutes) was performed to obtain the coating material.

[0028] (3) The coating material was pulsed plasma sprayed onto the substrate surface using an atmospheric plasma sprayer (purchased from Shenzhen Harrison Industrial Technology Co., Ltd., model: HRS-XATS-PD) (current 500 A, voltage 60 V, spraying frequency 150 Hz, distance 100 mm, coating thickness 0.4 mm).

[0029] (4) Graded heat treatment: The sprayed coating was treated at 600°C in a nitrogen atmosphere for 1 hour, and then heated to 900°C for 1 hour.

[0030] (5) Polish the heat-treated coating to a roughness Ra < 0.8 μm.

[0031] Example 2: Preparation of natural gas hydrogen-blended pipeline coating

[0032] This embodiment differs from embodiment 1 in that:

[0033] The raw materials of the natural gas hydrogen-blended pipeline coating of this embodiment include the following components in parts by weight: 55 parts of zirconium oxide (ZrO2), 8 parts of yttrium oxide (Y2O3), 18 parts of nano-alumina (Al2O3, particle size 60nm), 12 parts of nano-grade polytetrafluoroethylene (PTFE, particle size 90nm), 4 parts of silane coupling agent (KH-550), and 1 part of cerium oxide (CeO2).

[0034] In the preparation step (3), the plasma spraying current is 550A, the spraying frequency is 200Hz, and the spraying distance is 110mm.

[0035] Example 3: Preparation of natural gas hydrogen-blended pipeline coating

[0036] This embodiment differs from embodiment 1 in that:

[0037] 10 parts of nano-sized polytetrafluoroethylene (PTFE, particle size 50 nm) were replaced by 10 parts of nano-sized polyvinylidene fluoride (PVDF, particle size 50 nm).

[0038] In the preparation step (2), the ultrasonic dispersion time is extended to 40 minutes.

[0039] Example 4: Preparation of natural gas hydrogen-blended pipeline coating

[0040] This embodiment differs from embodiment 1 in that:

[0041] 10 parts of nano-sized polytetrafluoroethylene (PTFE, particle size 100 nm) were replaced by 10 parts of nano-sized polyperfluoroethylene propylene (FEP, particle size 100 nm).

[0042] In the preparation step (1), the grinding time is extended to 5 hours.

[0043] Example 5: Preparation of natural gas hydrogen-blended pipeline coating

[0044] The difference between this embodiment and embodiment 1 is that 3 parts of silane coupling agent (KH-550) are replaced by 3 parts of aminosilane (KH-560).

[0045] Example 6: Preparation of natural gas hydrogen-blended pipeline coating

[0046] The difference between this embodiment and embodiment 1 is that 3 parts of silane coupling agent (KH-550) are replaced by 3 parts of epoxy silane (KH-570).

[0047] Comparative Example 1: Preparation of natural gas hydrogen-blended pipeline coating

[0048] The difference between this comparative example and Example 1 is that the raw material of the natural gas hydrogen-blended pipeline coating material in this comparative example does not include yttrium oxide (Y2O3).

[0049] Comparative Example 2: Preparation of natural gas hydrogen-blended pipeline coating

[0050] The difference between this comparative example and Example 1 is that the raw material of the natural gas hydrogen-blended pipeline coating material in this comparative example does not include nano-alumina (Al2O3).

[0051] Comparative Example 3: Preparation of natural gas hydrogen-blended pipeline coating

[0052] The difference between this comparative example and Example 1 is that the raw material of the natural gas hydrogen-blended pipeline coating material in this comparative example does not include cerium oxide (CeO2).

[0053] Comparative Example 4: Preparation of natural gas hydrogen-blended pipeline coating

[0054] This comparative example differs from Example 1 in that 50 parts of zirconium oxide (ZrO 2 ) are replaced by 50 parts of titanium dioxide (TiO 2 ).

[0055] Comparative Example 5: Preparation of natural gas hydrogen-blended pipeline coating

[0056] The difference between this comparative example and Example 1 is that the raw materials of the natural gas hydrogen-blended pipeline coating material of this example include the following components in parts by weight: 50 parts of zirconium oxide (ZrO2), 5 parts of yttrium oxide (Y2O3), 15 parts of nano-alumina (Al2O3, particle size 80nm), 20 parts of nano-grade polytetrafluoroethylene (PTFE, particle size 70nm), 1 part of silane coupling agent (KH-550), and 0.2 parts of cerium oxide (CeO2).

[0057] Comparative Example 6: Preparation of natural gas hydrogen-blended pipeline coating

[0058] The difference between this comparative example and Example 1 is that in step (3), a conventional DC spraying method (current 500 A, voltage 60 V, frequency 0 Hz, distance 100 mm, thickness 0.4 mm) is adopted.

[0059] Comparative Example 7: Preparation of natural gas hydrogen-blended pipeline coating

[0060] The difference between this comparative example and Example 1 is that in step (3), the frequency of the pulsed plasma spraying is 300 Hz.

[0061] Comparative Example 8: Preparation of natural gas hydrogen-blended pipeline coating

[0062] The difference between this comparative example and Example 1 is that in step (3), the current of the pulse plasma spraying is 400A.

[0063] Comparative Example 9: Preparation of natural gas hydrogen-blended pipeline coating

[0064] The difference between this comparative example and Example 1 is that in step (3), the current of the pulse plasma spraying is 600A.

[0065] Comparative Example 10: Preparation of natural gas hydrogen-blended pipeline coating

[0066] The difference between this comparative example and Example 1 is that in step (3), the spraying distance of the pulse plasma spraying is 80 mm.

[0067] Comparative Example 11: Preparation of natural gas hydrogen-blended pipeline coating

[0068] The difference between this comparative example and Example 1 is that in step (3), the spraying distance of the pulse plasma spraying is 120 mm.

[0069] Comparative Example 12: Preparation of natural gas hydrogen-blended pipeline coating

[0070] The difference between this comparative example and Example 1 is that in step (4), heat treatment is directly performed at 900° C. for 2 hours.

[0071] Test example: Performance test of natural gas hydrogen-blended pipeline coating

[0072] This test example tests the performance of the natural gas hydrogen-blended pipeline coatings of the above-mentioned embodiments and comparative examples.

[0073] (1) Permeability test:

[0074] Test method: According to GB / T 34298-2017 "Hydrogen permeability test method", the test was carried out using a hydrogen permeometer at 5 MPa pressure and 50°C. The sample was a cross-section of a coated pipe (area 10 cm 2 ), and the steady-state permeability was calculated by the mass method.

[0075] Test process: Prepare the coating sample and seal it in the test device; pass high-purity hydrogen gas and record the permeation quality changes after stabilization for 24 hours; repeat the test three times, take the average value and calculate the standard deviation.

[0076] (2) Adhesion test:

[0077] Test method: Based on GB / T 8642-2002 "Determination of adhesion of thermal spray coatings", the test is conducted using the pull-off method. The sample is a coated cylinder with a diameter of 20 mm.

[0078] Test procedure: Bond a puller to the surface of the coating sample and cure with epoxy resin for 24 hours. Use a puller to load at a rate of 0.1 MPa / s until the coating peels off, and record the maximum tensile force. Repeat the test five times, take the average, and calculate the standard deviation.

[0079] (3) Hardness test:

[0080] Test method: According to GB / T 4340.1-2009 "Vickers hardness test for metallic materials", use Vickers hardness tester, load 0.5kg, indentation time 15s.

[0081] Test procedure: 10 points are randomly selected from the coating cross section for testing; the diagonal length of the indentation is measured and the hardness value is calculated; the average value is taken and the standard deviation is calculated.

[0082] (4) Preparation energy consumption test:

[0083] Test process: Use power meter to monitor the preparation of 1m 2 Total electrical energy consumption of the plasma spray equipment and heat treatment furnace when coating the samples.

[0084] (5) Corrosion resistance test:

[0085] Test method: Based on ASTM G31-72 "Metal Corrosion Test Methods", using the static immersion method.

[0086] Test process: The coating sample was weighed and placed in a 5% HCl solution corrosive solution. After soaking for 72 hours, it was taken out, cleaned, dried and weighed again to calculate the coating mass loss rate.

[0087] (6) The cross-sectional microstructure of the coating samples was analyzed using a scanning electron microscope (SEM).

[0088] Table 1 Performance test results of natural gas hydrogen-blended pipeline coatings in test examples

[0089]

[0090]

[0091] From the test results of the above embodiments and comparative examples, it can be concluded that, firstly, the natural gas hydrogen-blended pipeline coating obtained by compounding the components with specific contents in the embodiments of the present invention has a low permeability, which can effectively reduce the permeation rate of gases such as hydrogen inside the material, reduce the possibility of gas leakage, and provide a reliable safety guarantee for the transportation of natural gas hydrogen-blended. Secondly, the natural gas hydrogen-blended pipeline coating of the present invention has high adhesion, which means that the coating can be firmly attached to the surface of the pipeline, and can maintain a stable bonding state even under complex working conditions, such as temperature changes, mechanical vibrations, etc., and is not easy to fall off. At the same time, the natural gas hydrogen-blended pipeline coating of the present invention has high hardness and excellent corrosion resistance. It can resist physical damage such as scratches and collisions from external objects and chemical corrosion such as strong acids. It maintains the flatness and integrity of the coating surface in complex environments, is not prone to aging, decomposition and other performance degradation phenomena, extends the service life of the pipeline, and ensures the long-term stable operation of the pipeline.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A coating material, characterized in that: The invention comprises the following components in parts by weight: 50-55 parts of zirconium oxide, 15-18 parts of aluminum oxide, 5.5-9 parts of rare earth oxide, 10-12 parts of fluorocarbon polymer and 3-4 parts of silane coupling agent; the rare earth oxide comprises yttrium oxide and cerium oxide.

2. The coating material according to claim 1, wherein The mass ratio of the yttrium oxide to the cerium oxide is (8-10):

1.

3. The coating material according to claim 1, wherein The fluorocarbon polymer includes at least one of polytetrafluoroethylene, polyvinylidene fluoride and polyperfluoroethylene propylene.

4. The coating material according to claim 1, wherein The silane coupling agent includes at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane.

5. The coating material according to claim 1, wherein The particle size of the aluminum oxide is 50nm-100nm; the particle size of the fluorocarbon polymer is 50nm-100nm.

6. The method for preparing the coating material according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) mixing the zirconium oxide, aluminum oxide, and rare earth oxide, and grinding them to obtain a mixture; (2) adding the fluorocarbon polymer and the silane coupling agent to the mixture and performing ultrasonic dispersion to obtain the coating material.

7. A natural gas hydrogen-blended pipeline coating, characterized in that: Made of the coating material according to any one of claims 1 to 5.

8. The method for preparing the natural gas hydrogen-blended pipeline coating according to claim 7, characterized in that: The following steps are involved: The coating material is sprayed onto a substrate, subjected to heat treatment, and polished to obtain the natural gas hydrogen-blended pipeline coating.

9. The preparation method according to claim 8, wherein The spraying adopts pulse plasma spraying; the frequency of the pulse plasma spraying is 100Hz-200Hz, the current is 450A-550A, and the spraying distance is 90mm-110mm; the heat treatment adopts graded heat treatment; the graded heat treatment is carried out in the following stages: (1) the first stage: the temperature is 500℃-700℃, and the time is 0.5h-2h; (2) the second stage: the temperature is 800℃-1000℃, and the time is 0.5h-2h.

10. Use of the coating material according to any one of claims 1 to 5 and the natural gas hydrogen-blended pipeline coating according to claim 7 in the field of energy transportation.

Images