Multifunctional nano composite ceramic coating and preparation method thereof

Abstract

The invention belongs to the technical field of ceramic coatings. The invention provides a multifunctional nano-composite ceramic coating. The multifunctional nano-composite ceramic coating is formed by curing and sintering oxide nano-particles, an adhesive and water. According to the multifunctional nano-composite ceramic coating disclosed by the invention, by adding the organic and inorganic adhesives and forming atomic-scale solid-solution oxide nanoparticles through permeation with a metal matrix, the thermal adaptation between the coating and the matrix is increased, and the binding force between the coating and the matrix is improved; the coating has excellent salt spray corrosion resistance, hydrogen resistance, wear resistance and high temperature resistance, and can meet the coating requirements of the inner and outer surfaces of a metal component. Moreover, the preparation process is simple, the cost is low, and the requirements of large-scale production can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic coating, in particular to a multifunctional nano-composite ceramic coating and a preparation method thereof. BACKGROUND

[0002] The southeast coastal areas of China are located in the subtropical monsoon climate zone, with high temperature, high humidity and high salt fog all the year round, the average annual relative humidity is more than 80%, and the salt fog deposition is 0.3-1.5mg / (dm 2 ·d), which causes serious corrosion of steel components serving along the coast, resulting in a service life of 30%-50% of that in the conventional environment. The equipment in the deep sea will not only be corroded and abraded by seawater, but also cause hydrogen permeation in the metal material due to the existence of water pressure, causing hydrogen embrittlement of the material.

[0003] Hydrogen energy is praised as the most potential secondary energy due to its non-pollution. Hydrogen storage is an important link in the industrialization development of hydrogen energy. High-pressure hydrogen storage has become the dominant way in current industrial applications due to its simple equipment structure, fast filling speed and other advantages, but the high-pressure hydrogen environment can reduce the plasticity of materials, accelerate the fatigue crack propagation rate and hydrogen embrittlement problem, which is a great challenge to the safety of high-pressure hydrogen system. On the other hand, in the development of advanced nuclear energy in China, new reactor vessels also face the problem of hydrogen embrittlement of the reactor vessel components caused by hydrogen permeation. Hydrogen permeation will cause many performance degradation of materials, not only causing the loss of raw materials, but also causing the substrate material to appear "hydrogen embrittlement" and other problems, and in more serious cases, causing radioactive pollution. The current hydrogen barrier coating is basically aluminum oxide and its composite, which has insufficient wear resistance and corrosion resistance, and is mainly prepared by aluminizing, magnetron sputtering and spin coating, which is difficult to scale up and difficult to meet the engineering application requirements, so it is urgent to develop a hydrogen barrier coating that can be used in engineering applications, while also having wear resistance.

[0004] The current mainstream corrosion prevention methods (such as hot dip galvanizing, epoxy coating, and cathodic protection) have significant defects: 1. Insufficient corrosion resistance: traditional organic coatings are prone to peeling and pulverization in salt spray environment, with a protection period generally less than 5 years; 2. Lack of wear resistance: under the combined action of mechanical wear and marine biological erosion, the coating is easily damaged and causes localized corrosion to spread, and frequent maintenance will lead to an increase in the total life cycle cost; 3. There is no coating that combines corrosion resistance, wear resistance and hydrogen resistance in one. Ceramic composite coatings, with their high hardness, chemical inertness and dense structure, have the characteristics of corrosion resistance, wear resistance, environmental protection and no pollution, and can become a multi-layer coating material that resists corrosion, wear and hydrogen. Therefore, it has good application prospects to research and develop a multifunctional nano-composite ceramic coating and a preparation method thereof. SUMMARY

[0005] The present application aims at providing a multifunctional nano-composite ceramic coating and a preparation method thereof to overcome the deficiencies of the prior art.

[0006] To achieve the above-mentioned application purposes, the present application provides the following technical solutions.

[0007] The present application provides a multifunctional nano-composite ceramic coating, which is prepared by solidification sintering of oxide nanoparticles, a binder and water.

[0008] Preferably, the oxide nanoparticles contain the following components: alpha-alumina, silicon dioxide, manganese oxide, zinc oxide, calcium oxide and potassium oxide.

[0009] The particle size of the components contained in the oxide nanoparticles is 50-100 nm.

[0010] Preferably, the binder comprises an organic binder and an inorganic binder.

[0011] The organic binder is a silane coupling agent, and the inorganic binder is sodium silicate.

[0012] Preferably, the mass percentage of all components of the multifunctional nano-composite ceramic coating is as follows: alpha-alumina 5-8%, silicon dioxide 10-15%, manganese oxide 1-3%, zinc oxide 3-6%, calcium oxide 10-13%, potassium oxide 5-7%, silane coupling agent 10-15%, water 10-13%, and the rest is sodium silicate.

[0013] Preferably, the solidification sintering temperature is 500-800℃, the solidification sintering time is 20-40 min, the solidification sintering is carried out in an oxygen-rich atmosphere, and the temperature rising rate to the solidification sintering temperature is 4-6℃ / min.

[0014] The present application also provides a preparation method of the multifunctional nano-composite ceramic coating, which comprises the following steps.

[0015] 1) Pretreating the substrate;

[0016] 2) Mixing the oxide nanoparticles, the binder and water in a certain proportion to obtain a coating;

[0017] 3) Spraying the coating on the surface of the substrate, then solidification sintering to obtain the multifunctional nano-composite ceramic coating.

[0018] Preferably, the substrate in step 1) is stainless steel, carbon steel or nickel alloy; and the shape of the substrate is a round tube or a round sheet.

[0019] Preferably, the pretreatment in step 1) is sandpaper polishing treatment or sand blasting treatment.

[0020] Preferably, the parameters to be controlled in the spraying process in step 3) are as follows: the spraying temperature is 20-30℃, the spraying time is 10-30s, the atomization gas pressure is 0.3-0.5MPa, the pressure of the powder supply pot is 0.04-0.10MPa, and the distance between the nozzle of the spraying gun and the surface of the substrate is 150-300mm.

[0021] Preferably, after the spraying in step 3) is completed, the obtained coating is dried.

[0022] The drying temperature is 130-150℃, and the drying time is 20-40min.

[0023] The present application has the following advantages:

[0024] 1) The multifunctional nano composite ceramic coating prepared by the present application can be used for corrosion resistance, wear resistance and hydrogen permeation resistance protection of different metal parts.

[0025] 2) The thermal expansion coefficient of the multifunctional nano composite ceramic coating prepared by the present application can be well adapted to the steel substrate (stainless steel, carbon steel) substrate, has good bonding force (>60MPa) and synchronous deformation ability, the bonding force between the coating and the substrate is >50MPa; the surface is dense and uniform, without microcracks, pinholes and other defects; has very good high temperature fatigue resistance, the service temperature of the coating is room temperature-800℃; the hardness of the coating is high, more than 2 times the hardness of the stainless steel substrate; the room temperature friction coefficient is 0.6, close to 316L stainless steel; the hydrogen blocking factor is high, >10 under the condition of 1MPa pressure and 550℃. 4 ; has strong salt spray corrosion resistance, can resist neutral salt spray corrosion with a NaCl concentration of 5% and a temperature of 35-40℃ for 1000h (no corrosion points are observed by SEM).

[0026] 3) After the component heat treatment of the multifunctional nano composite ceramic coating of the present application, a more stable eutectic oxide system is formed by chemical reaction, and part of the elements are segregated at the interface and penetrate into the substrate and the metal substrate to form an atomic level solid solution, which strengthens the bonding force between the coating and the metal substrate surface, and the dense silicon oxide, aluminum oxide and titanium oxide cooperate to hinder the diffusion of hydrogen atoms.

[0027] 4) The preparation process of the present application is simple and low in cost, and can meet the demand of large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1A photograph of the multifunctional nanocomposite ceramic coating on the outer wall of the 316L stainless steel pipe in Example 1;

[0029] Figure 2 A photograph of the multifunctional nanocomposite ceramic coating on the outer wall of the 316L stainless steel pipe in Example 1;

[0030] Figure 3 A photograph of the multifunctional nanocomposite ceramic coating on the outer wall of the 316L stainless steel pipe in Example 1;

[0031] Figure 4 A photograph of the multifunctional nanocomposite ceramic coating on the outer wall of the 316L stainless steel pipe in Example 1;

[0032] Figure 5 A photograph of the multifunctional nanocomposite ceramic coating on the outer wall of the 316L stainless steel pipe in Example 1;

[0033] Figure 6 A photograph of the multifunctional nanocomposite ceramic coating on the outer wall of the 316L stainless steel pipe in Example 1;

[0034] Figure 7 A photograph of the multifunctional nanocomposite ceramic coating on the outer wall of the 316L stainless steel pipe in Example 1;

[0035] Figure 8 A photograph of the multifunctional nanocomposite ceramic coating on the outer wall of the 316L stainless steel pipe in Example 1; DETAILED DESCRIPTION

[0036] The present application provides a multifunctional nanocomposite ceramic coating, which is formed by solidification sintering of oxide nanoparticles, a binder and water.

[0037] In the present application, the oxide nanoparticles preferably comprise α-alumina, silicon dioxide, manganese oxide, zinc oxide, calcium oxide and potassium oxide.

[0038] The particle size of the components contained in the oxide nanoparticles is preferably 50-100 nm, further preferably 60-90 nm, and more preferably 70-80 nm.

[0039] In the present application, the binder preferably comprises an organic binder and an inorganic binder.

[0040] The organic binder is preferably a silane coupling agent, and the inorganic binder is preferably sodium silicate.

[0041] In the present application, the mass percentage of all components of the multifunctional nanocomposite ceramic coating is preferably: 5-8% of α-alumina, 10-15% of silicon dioxide, 1-3% of manganese oxide, 3-6% of zinc oxide, 10-13% of calcium oxide, 5-7% of potassium oxide, 10-15% of silane coupling agent, 10-13% of water, and the rest is sodium silicate, further preferably: 6-7% of α-alumina, 12-14% of silicon dioxide, 1.5-2.5% of manganese oxide, 4-5% of zinc oxide, 11-12% of calcium oxide, 5.5-6.5% of potassium oxide, 12-14% of silane coupling agent, 11.5-12.5% of water, and the rest is sodium silicate, and more preferably: 6.5% of α-alumina, 13% of silicon dioxide, 2% of manganese oxide, 4.5% of zinc oxide, 11.5% of calcium oxide, 6% of potassium oxide, 13% of silane coupling agent, 12% of water, and the rest is sodium silicate.

[0042] In the present application, the temperature for solidification sintering is preferably 500-800℃, further preferably 600-700℃, and more preferably 650℃; the time for solidification sintering is preferably 20-40 min, further preferably 25-35 min, and more preferably 30 min; the solidification sintering is preferably carried out in an oxygen-rich atmosphere, further preferably in an air atmosphere; and the heating rate for heating to the solidification sintering temperature is preferably 4-6℃ / min, and further preferably 5℃ / min.

[0043] The present application also provides a preparation method of the multifunctional nanocomposite ceramic coating, comprising the following steps:

[0044] 1) pretreating the substrate;

[0045] 2) mixing the oxide nanoparticles, the binder, and water in a certain proportion to obtain a coating;

[0046] 3) spraying the coating on the surface of the substrate, and then performing solidification sintering to obtain the multifunctional nanocomposite ceramic coating.

[0047] In the present application, the substrate in step 1) is preferably stainless steel, carbon steel, or nickel alloy; and the shape of the substrate is preferably a round pipe or a round sheet.

[0048] In the present application, the pretreatment in step 1) is preferably sandpaper polishing or sandblasting.

[0049] In the present application, the sandpaper polishing is preferably performed using 80# sandpaper.

[0050] In the present application, the sandblasting medium for the sandblasting treatment is preferably steel sand, the mesh number of the steel sand is preferably 80-120 mesh, further preferably 100 mesh, the pressure for the sandblasting is preferably 4-6 MPa, further preferably 5 MPa, the temperature for the sandblasting is preferably 20-30℃, further preferably 25℃, and the time for the sandblasting is preferably 1-3 h, further preferably 2 h.

[0051] In the present application, the pretreatment can increase the roughness of the surface of the substrate.

[0052] In the present application, after the pretreatment in step 1), the surface of the substrate is preferably cleaned using anhydrous ethanol.

[0053] In the present application, the cleaning of the surface of the substrate using alcohol can remove impurities and attachments on the surface of the substrate.

[0054] In the present application, the parameters to be controlled during the spraying process in step 3) are as follows: the temperature for the spraying is preferably 20-30℃, further preferably 25℃; the time for the spraying is preferably 10-30 s, further preferably 15-25 s, and more preferably 20 s; the atomization gas pressure is preferably 0.3-0.5 MPa, further preferably 0.35-0.45 MPa, and more preferably 0.4 MPa; the pressure of the powder supply pot is preferably 0.04-0.1 MPa, further preferably 0.05-0.08 MPa, and more preferably 0.06-0.07 MPa; and the distance between the nozzle of the spray gun and the surface of the substrate is preferably 150-300 mm, further preferably 180-220 mm, and more preferably 200 mm.

[0055] In the present application, after the spraying in step 3), the coating is preferably dried; the temperature for the drying is preferably 130-150℃, further preferably 135-145℃, and more preferably 140℃; and the time for the drying is preferably 20-40 min, further preferably 25-35 min, and more preferably 30 min.

[0056] The technical solutions provided by the present application will be described in detail below in conjunction with the examples, but they should not be understood as limiting the scope of protection of the present application.

[0057] In Examples 1-2, the particle size of the components contained in the oxide nanoparticles is 100 nm;

[0058] In Example 3, the particle size of the components contained in the oxide nanoparticles is 80 nm.

[0059] Example 1

[0060] A 316L stainless steel pipe with a diameter of 20 mm and a length of 100 mm was sandblasted, the sandblasting medium was 100 mesh steel sand, the sandblasting pressure was 5 MPa, the sandblasting temperature was 25°C, and the sandblasting time was 2 h. It was then cleaned with anhydrous ethanol for 10 min and dried for use. 200 g of slurry was prepared by mixing α-alumina, silicon dioxide, manganese oxide, zinc oxide, calcium oxide, potassium oxide, silane coupling agent, water and sodium silicate in a mass percentage of 8:15:3:3:10:5:10:10:36, and then the slurry was evenly stirred to obtain a coating.

[0061] The coating was sprayed on the surface of the stainless steel pipe at a spraying temperature of 25°C, a spraying time of 20s, an atomizing air pressure of 0.3MPa, a powder supply pot pressure of 0.06MPa, and a distance of 200mm between the spray gun nozzle and the surface of the stainless steel pipe. After the spraying was completed, the obtained coating was dried at 130°C for 40min, and then heated to 600°C at a heating rate of 5°C / min in an air atmosphere, and cured and sintered at this temperature for 30min, and cooled with the furnace to obtain a multifunctional nano-composite ceramic coating.

[0062] The actual picture of the multifunctional nanocomposite ceramic coating prepared in this embodiment is as follows: Figure 1 As shown by Figure 1 It can be seen that the surface of the multifunctional nanocomposite ceramic coating is smooth and dense, with a glaze-like luster, and the cross-sectional view shows a thickness of about 45 microns;

[0063] The tritium penetration test results of the multifunctional nanocomposite ceramic coating and the surface morphology and element distribution after salt spray corrosion resistance are shown in the figure. Figure 2 As shown, (a) is the tritium penetration test result of the multifunctional nanocomposite ceramic coating, (b) is the surface morphology and element distribution of the multifunctional nanocomposite ceramic coating after salt spray corrosion resistance. Figure 2 The results show that the multifunctional nanocomposite ceramic coating significantly reduces deuterium flux in the temperature range of 350-650°C, indicating its excellent deuterium-blocking performance in high-temperature deuterium shielding applications. In particular, in the high-temperature range (550-650°C), the coating almost completely inhibits deuterium penetration, providing strong support for thermal control and deuterium load protection. The multifunctional nanocomposite ceramic coating also has strong salt spray corrosion resistance. Under the conditions of NaCl concentration of 5% and temperature of 35°C, no corrosion spots were observed on the surface after 1000 hours of salt spray corrosion.

[0064] The wear resistance of 316L stainless steel and multifunctional nanocomposite ceramic coating is shown in the figure Figure 3 As shown, (a) is the friction coefficient of 316L stainless steel, (b) is the friction and wear of 316L stainless steel, (c) is the friction coefficient of the coating under the same experimental conditions, and (d) is the friction and wear result of the coating under the same experimental conditions. Figure 3It can be seen that the wear resistance of the coating is good, close to the wear resistance of stainless steel.

[0065] The hardness diagram of 316L stainless steel and multifunctional nano composite ceramic coating is shown in Figure 4 It can be seen that the hardness of the coating is more than twice the hardness of the stainless steel substrate. Figure 4

[0066] Example 2

[0067] A DH40 steel pipe with a diameter of 200 mm and a length of 500 mm is sandblasted, the sandblasting medium is 100 mesh steel sand, the sandblasting pressure is 5 MPa, the sandblasting temperature is 25℃, and the sandblasting time is 2h, then it is cleaned with anhydrous ethanol for 10min, and dried for use; 200g of slurry is prepared by mixing α-alumina, silica, manganese oxide, zinc oxide, calcium oxide, potassium oxide, silane coupling agent, water and sodium silicate in a mass ratio of 8:15:3:3:10:5:10:10:36, then the slurry is uniformly stirred to obtain a coating.

[0068] The coating is sprayed on the surface of the DH40 steel pipe, the spraying temperature is 25℃, the spraying time is 20s, the atomizing gas pressure is 0.4MPa, the powder pot pressure is 0.1MPa, the distance between the spray gun mouth and the surface of the DH40 steel pipe is 150mm, after spraying, the obtained coating is dried at 150℃ for 30min, then it is heated to 600℃ at a heating rate of 5℃ / min in air atmosphere, and sintered at this temperature for 30min, and cooled in the furnace to obtain a multifunctional nano composite ceramic coating.

[0069] The actual picture of the multifunctional nano composite ceramic coating prepared in this example is shown in Figure 5 It can be seen that a smooth and flat composite ceramic coating with enamel gloss is generated on the surface of the DH40 steel pipe. Figure 5

[0070] The wear resistance of the DH40 steel pipe and the multifunctional nano composite ceramic coating of this example, and the deuterium permeation results of the multifunctional nano composite ceramic coating are shown in Figure 6 (a) is the deuterium permeation experimental results of the multifunctional nano composite ceramic coating, (b) is the wear resistance diagram of the DH40 steel pipe, and (c) is the wear resistance diagram of the multifunctional nano composite ceramic coating, from which Figure 6 It can be seen from (a) that the hydrogen resistance factor PRF is 5120 at 650℃, PRF is 14000 at 550℃, and PRF is 13000 at 500℃, from (b) and (c) that the friction coefficient of the coating is 0.6, the friction coefficient of stainless steel is 0.5, and the friction and wear rate is about 1.2 times that of stainless steel, indicating that the hydrogen resistance performance of the coating is PRF>10 at 300-650℃.​​3 , the coating has very good hydrogen barrier and wear resistance;

[0071] The surface morphology and element distribution of the multifunctional nanocomposite ceramic coating after salt spray corrosion resistance are shown in the figure. Figure 7 As shown by Figure 7 It can be seen that under the conditions of NaCl concentration of 5% and temperature of 35℃, after 1000h of salt spray corrosion, the coating surface is smooth, the elements are distributed very evenly, and there is basically no damage.

[0072] Example 3

[0073] An Inconel 625 nickel alloy tube with a diameter of 150 mm and a length of 400 mm was polished with 80# sandpaper for 10 minutes, then cleaned with anhydrous ethanol for 12 minutes, and dried for use; 200 g of slurry was prepared by mixing α-alumina, silicon dioxide, manganese oxide, zinc oxide, calcium oxide, potassium oxide, silane coupling agent, water and sodium silicate in a mass percentage of 5:10:1:6:13:7:15:13:30, and then the slurry was uniformly stirred to obtain a coating.

[0074] The coating was sprayed on the surface of the Inconel 625 alloy tube at a spraying temperature of 30°C, a spraying time of 10s, an atomizing air pressure of 0.5MPa, a powder supply pot pressure of 0.04MPa, and a distance of 300mm between the spray gun nozzle and the surface of the nickel alloy tube. After spraying, the obtained coating was dried at 140°C for 20min, and then heated to 800°C in an air atmosphere at a heating rate of 6°C / min, and cured and sintered at this temperature for 20min, and cooled with the furnace to obtain a multifunctional nano-composite ceramic coating.

[0075] The multifunctional nanocomposite ceramic coating prepared in this embodiment was kept at 500℃, 700℃ and 800℃ for 48h respectively. Figure 8 As shown by Figure 8 It can be seen that after the coating is kept warm at different temperatures, the surface is intact and bright without any damage, indicating that it has good high temperature resistance.

[0076] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A multifunctional nanocomposite ceramic coating, characterized in that: The multifunctional nano-composite ceramic coating is formed by solidifying and sintering oxide nano-particles, a binder and water.

2. The multifunctional nanocomposite ceramic coating according to claim 1, characterized in that: The oxide nanoparticles comprise the following components: α-aluminum oxide, silicon dioxide, manganese oxide, zinc oxide, calcium oxide and potassium oxide; The particle size of the components contained in the oxide nanoparticles is 50 to 100 nm.

3. The multifunctional nanocomposite ceramic coating according to claim 1 or 2, characterized in that: The adhesive includes an organic adhesive and an inorganic adhesive; The organic binder is a silane coupling agent, and the inorganic binder is sodium silicate.

4. The multifunctional nanocomposite ceramic coating according to claim 3, characterized in that: The mass percentages of all components of the multifunctional nanocomposite ceramic coating are as follows: 5-8% of α-alumina, 10-15% of silicon dioxide, 1-3% of manganese oxide, 3-6% of zinc oxide, 10-13% of calcium oxide, 5-7% of potassium oxide, 10-15% of silane coupling agent, 10-13% of water, and the rest being sodium silicate.

5. The multifunctional nanocomposite ceramic coating according to claim 4, characterized in that: The curing and sintering temperature is 500-800° C., the curing and sintering time is 20-40 minutes, the curing and sintering is carried out in an oxygen-rich atmosphere, and the heating rate to the curing and sintering temperature is 4-6° C. / min.

6. The method for preparing the multifunctional nanocomposite ceramic coating according to any one of claims 1 to 5, characterized in that: The following steps are included: 1) Pre-treating the substrate; 2) mixing the oxide nanoparticles, the binder, and water in proportion to obtain a coating; 3) Spraying the coating onto the surface of the substrate, and then curing and sintering the coating to obtain a multifunctional nano-composite ceramic coating.

7. The preparation method according to claim 6, characterized in that Step 1) The substrate is made of stainless steel, carbon steel or nickel alloy; the substrate is in the shape of a round tube or a disc.

8. The preparation method according to claim 6 or 7, characterized in that The pretreatment in step 1) is sandpaper polishing or sandblasting.

9. The preparation method according to claim 8, characterized in that Step 3) The parameters that need to be controlled during the spraying process are: spraying temperature of 20-30°C, spraying time of 10-30s, atomizing air pressure of 0.3-0.5MPa, powder supply pot pressure of 0.04-0.1MPa, and the distance between the spray gun nozzle and the substrate surface of 150-300mm.

10. The preparation method according to claim 9, characterized in that After step 3) the spraying is completed, the coating is dried; The drying temperature is 130-150°C, and the drying time is 20-40 minutes.

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