Method for preparing cobalt phosphate nanopowder and coating, coating preparation and application thereof
Cobalt phosphate nanoparticles with controllable morphology were prepared by hydrothermal/solvothermal methods and then combined with epoxy resin to form a corrosion-resistant coating. This method overcomes the shortcomings of existing cobalt phosphate synthesis methods, achieves efficient and low-consumption coating preparation, and improves the anti-corrosion performance and adhesion of the coating.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI XUANYANG CHEM MATERIAL TECH CO LTD
- Filing Date
- 2024-03-14
- Publication Date
- 2026-07-21
AI Technical Summary
Existing methods for synthesizing cobalt phosphate suffer from high costs, low yields, demanding equipment requirements, and high impurity content, making it difficult to prepare cobalt phosphate nanopowders with controllable morphology. Furthermore, existing coatings lack sufficient adhesion and corrosion resistance.
Cobalt phosphate nanopowder was synthesized using a hydrothermal/solvothermal method. By controlling the hydrothermal reaction conditions and solvothermal parameters, cobalt phosphate nanopowder with controllable morphology was prepared. The nanopowder was then mixed with epoxy resin to form a corrosion-resistant coating, which was then sprayed onto the surface of a substrate.
This method enables the simple, efficient, and low-consumption preparation of cobalt phosphate nanopowder, improving the adhesion and corrosion resistance of coatings and protecting the substrate from pollution, moisture, and mechanical damage.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of new coating materials, and in particular to a method for preparing cobalt phosphate nanopowder and its coating, coating preparation and application. Background Technology
[0002] Cobalt phosphate micro / nanomaterials, due to their novel and unique properties—magnetic, catalytic, and photocatalytic properties—and their significant corrosion resistance in coatings, have become a hot research area for many research groups. However, cobalt phosphate has a rich variety of phases, making the preparation of cobalt phosphate nanopowders with a defined stoichiometric ratio extremely difficult. Therefore, developing a simple and feasible synthetic method for preparing cobalt phosphate nanocrystals with controllable phase and morphology remains a significant challenge for materials science researchers. Transition metal phosphates, with their abundant reserves, low cost, and ease of preparation, have become a research hotspot due to their potential optical, electrical, magnetic, and catalytic properties. Furthermore, transition phosphates exhibit strong electrochemical activity, making them potential substitutes for noble metals. Currently, common methods for preparing cobalt phosphate include: one involves reacting soluble cobalt salts with phosphates to form cobalt phosphate precipitates; another involves heating cobalt pyrophosphate hydrate and water in a sealed tube to 250°C to obtain cobalt phosphate; and a third involves preparing nanopowders using microwave irradiation.
[0003] Currently, among the common methods for synthesizing cobalt phosphate, Method 1 involves reacting soluble cobalt salts with phosphates to form cobalt phosphate precipitate. While this method is inexpensive, it results in high impurity content. Method 2 involves heating cobalt pyrophosphate hydrate and water in a sealed tube to 250°C, but this method suffers from low yield and high cost. Method 3 involves preparing cobalt phosphate nanopowder using microwave irradiation, but this method requires sophisticated equipment and has a complex preparation process, which can limit the industrialization of cobalt phosphate nanopowder. Therefore, this invention was developed to address these challenges. Summary of the Invention
[0004] This summary is provided to introduce, in a simplified form, some concepts that will be further described in the following detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
[0005] The technical problem to be solved by this invention is to overcome the shortcomings of existing technologies. One objective is to provide a simple, efficient, low-consumption method for preparing cobalt phosphate powder materials with easily controllable product morphology. The second objective is to provide a coating with good adhesion and corrosion resistance, and to promote its application. To this end, this invention proposes the following technical solution:
[0006] This invention first provides a method for preparing cobalt phosphate nanopowder, characterized by comprising the following steps:
[0007] Dissolve sodium dihydrogen phosphate dihydrate in water to form a sodium dihydrogen phosphate dihydrate solution;
[0008] Hexamethylenetetramine is dissolved in an organic solvent to form a hexamethylenetetramine solution;
[0009] A mixed solution of sodium dihydrogen phosphate dihydrate and hexamethylenetetramine solution was formed, and then cobalt nitrate hexahydrate was added. After hydrothermal and solvothermal reactions, a suspension was obtained. After cooling, precipitation, centrifugation, washing, and drying, cobalt phosphate nanoparticles were obtained. The chemical reaction formula for the preparation of cobalt phosphate is as follows: 3Co(NO3)2+2NaH2PO4=Co3(PO4)2+2NaNO3+4HNO3.
[0010] Preferably, it satisfies one or more of the following characteristics:
[0011] The pressure conditions for the hydrothermal solvothermal reaction are 0.3-4 MPa, preferably 0.5 MPa;
[0012] The temperature conditions for the hydrothermal solvothermal reaction are 110-250℃, preferably 130℃; the time is 0.5-15h, preferably 3h.
[0013] The drying temperature for the hydrothermal solvothermal reaction is 30-110℃, preferably 60℃; the drying time is 6-24h, preferably 12h.
[0014] Anhydrous ethanol is used as the organic solvent.
[0015] Preferably, during the hydrothermal and solvothermal reaction, the reaction solution is transferred to a polytetrafluoroethylene-lined stainless steel autoclave.
[0016] The present invention also provides a corrosion-resistant coating containing cobalt phosphate nanoparticles, characterized in that it comprises 5-15 parts of epoxy resin emulsion, 1-5 parts of curing agent, and 1-2 parts of cobalt phosphate nanoparticles prepared by the above-mentioned cobalt phosphate nanoparticle preparation method.
[0017] Preferably, it satisfies one or more of the following characteristics:
[0018] The epoxy resin emulsion is preferably 6 parts;
[0019] The curing agent is preferably 1 part;
[0020] The preferred amount of cobalt phosphate nanopowder is 2 parts;
[0021] The water-based curing agent is selected from one or a combination of water-soluble polyamide, Amkorwyn 100, and Amkorwyn 287.
[0022] This invention also provides a method for preparing a corrosion-resistant coating containing cobalt phosphate nanopowder, characterized by comprising the following steps:
[0023] Add 1-2 parts of cobalt phosphate nanopowder to 5-15 parts of epoxy resin emulsion and stir to obtain component A;
[0024] Add 1-5 parts of curing agent to component A and stir evenly to obtain component B;
[0025] The mixture of component B was defoamed under vacuum to obtain a corrosion-resistant emulsion containing cobalt phosphate nanopowder;
[0026] After the corrosion-resistant emulsion containing cobalt phosphate nanopowder is sprayed onto the substrate and dried, it is cured at 50-110℃ for 6-24 hours.
[0027] Preferably, it satisfies one or more of the following characteristics:
[0028] The epoxy resin emulsion is preferably 6 parts;
[0029] The curing agent is preferably 1 part;
[0030] The preferred amount of cobalt phosphate nanopowder is 2 parts;
[0031] The water-based curing agent is selected from one or a combination of water-soluble polyamide, Amkorwyn 100, and Amkorwyn 287.
[0032] Preferably, the drying temperature of the corrosion-resistant emulsion spraying substrate containing cobalt phosphate nanopowder after drying is 60°C, and the curing time is 6 hours.
[0033] The present invention also provides an application of a corrosion-resistant coating containing cobalt phosphate nanopowder, characterized in that the above-mentioned corrosion-resistant coating containing cobalt phosphate nanopowder is applied to the corrosion protection of a substrate.
[0034] Preferably, the substrate is a fiber material.
[0035] The beneficial effects achieved by this invention due to the adoption of the above technical solution are as follows:
[0036] Cobalt phosphate micro / nanomaterials with specific morphologies and phases were prepared using a simple hydrothermal / solvothermal synthesis method. By controlling experimental parameters, the morphology and phase of the target product under hydrothermal / solvothermal conditions were successfully synthesized. A waterborne epoxy composite material was formed by mixing cobalt phosphate nanopowder with waterborne epoxy resin, improving the corrosion resistance of the epoxy resin coating. This composite material was then sprayed onto fiber materials using a simple spraying technique to form an anti-corrosion coating, preventing contamination, moisture absorption, oxidation, and mechanical damage to the optical fiber, thereby protecting the strength and optical properties of the fiber material.
[0037] Compared to other methods, the hydrothermal-solvothermal method offers advantages such as simplicity, high efficiency, low consumption, and easy control over product morphology. The cobalt phosphate powder prepared by the hydrothermal synthesis method is extremely fine, with particle sizes reaching the nanometer level. Detailed Implementation
[0038] The preferred embodiments described below are merely examples, and other obvious variations will be apparent to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.
[0039] Preparation of cobalt phosphate nanopowder:
[0040] 20 mmol of sodium dihydrogen phosphate dihydrate (NaH2PO4·2H2O) and 12 mmol of hexamethylenetetramine (HMT) were dissolved in solutions containing 90 mL of water and 10 mL of anhydrous ethanol, respectively. 4 mmol of cobalt nitrate hexahydrate (Co(NO3)2·6H2O) was added to the mixed solution and stirred for 30 min to obtain a homogeneous solution. The homogeneous solution was then added to a 150 mL autoclave lined with polytetrafluoroethylene and heat-treated at 110-250 °C for 0.5-15 h to obtain a sample. After the sample (suspension) was naturally cooled to room temperature, the precipitate was centrifuged and washed several times in water and anhydrous ethanol. Finally, the precipitate was dried in an oven at 30-110 °C for 6-24 h to obtain cobalt phosphate nanoparticles. The yield of cobalt phosphate nanoparticles was 92.5%, and the purity was 98.5%.
[0041] HMT acts as a pH regulator; as the reaction temperature gradually increases, HMT hydrolyzes and releases NH3, thus regulating the pH of the reaction system. HMT affects the morphology of cobalt phosphate nanopowder and the pH of the solution; controlling the Co... 2+ With (PO4) 3- Co 2+ When the molar ratio of HMT is 1:3, it presents a flower-like structure with a width of approximately 2.5 μm and a thickness of approximately 190 nm. With increasing HMT concentration, it forms elongated nanoribbons with a width of approximately 0.4 μm and a thickness of approximately 25 μm.
[0042] HMT undergoes hydrolysis in water in the following reaction:
[0043] (CH2)6N4 + H2O → 6HCHO + NH3
[0044]
[0045] Based on the above preparation method, the sample preparation conditions were changed as shown in Table 1 below:
[0046] Table 1 Sample preparation conditions
[0047]
[0048]
[0049] The following sample properties were obtained based on the sample preparation conditions in Table 1:
[0050] Table 2 Sample Properties
[0051] 1 flower shape <![CDATA[Co3(PO4)2·8H2O]]> pink 2.5k / 190 2 Nanoribbons <![CDATA[Co3(PO4)2·8H2O]]> violet 400 / 25 3 flower shape <![CDATA[Co3(PO4)2·8H2O]]> pink 2.5k / 190 4 Nanoribbons <![CDATA[Co3(PO4)2·4H2O]]> violet 200 / 25 5 cotton-like <![CDATA[Co3(PO4)2·4H2O]]> violet 150 / 20 6 Nanosheets <![CDATA[Co3(PO4)2·4H2O]]> violet 500 / 50 7 Nanosheets <![CDATA[Co3(PO4)2·4H2O]]> violet 500 / 50 8 Nanoribbons <![CDATA[Co3(PO4)2·4H2O]]> violet 170 / 28 9 cotton-like <![CDATA[Co3(PO4)2·4H2O]]> violet 155 / 20
[0052] Therefore, cobalt phosphide micro / nanomaterials with specific morphologies and phases were prepared by using a simple hydrothermal / solvothermal synthesis method. By controlling the experimental parameters, the morphology and phase of the target product under hydrothermal / solvothermal conditions were successfully synthesized.
[0053] Example 1:
[0054] 2g of the prepared cobalt phosphate nanoparticles (sample 1) were added to 6g of epoxy resin emulsion and stirred evenly for 10min to obtain component A; 1g of water-soluble polyamide was added to component A and stirred for 20min to obtain component B; the resulting mixture component B was defoamed in a vacuum laboratory; the mixture was sprayed onto the surface of plastic fibers using a spray gun with a spray pressure of 0.3MPa and a spray gun distance of 20cm; the sprayed plastic fibers were left to dry for 2 hours, and then placed in an oven at 60℃ for 6 hours for curing.
[0055] Example 2:
[0056] 1g of cobalt phosphate nanopowder (sample 2) was added to 5g of epoxy resin emulsion and stirred evenly for 10min to obtain component A; 1g of Amkor White 100 was added to component A and stirred for 20min to obtain component B; the resulting mixture component B was defoamed in a vacuum laboratory; the mixture was sprayed onto the surface of plastic fiber using a spray gun with a spray pressure of 0.3MPa and a spray gun distance of 20cm; the sprayed plastic fiber was left to dry for 2 hours, and then placed in an oven at 50℃ for 6 hours to cure.
[0057] Example 3:
[0058] 2g of cobalt phosphate nanopowder (sample 4) was added to 15g of epoxy resin emulsion and stirred evenly for 10min to obtain component A; 1g of benzo[a]methoxygen 287 was added to component A and stirred for 20min to obtain component B; the resulting mixture component B was defoamed in a vacuum laboratory; the mixture was sprayed onto the surface of plastic fiber using a spray gun with a spray pressure of 0.3MPa and a spray gun distance of 20cm; the sprayed plastic fiber was left to dry for 2 hours, and then placed in an oven at 100℃ for 10 hours to cure.
[0059] Example 4:
[0060] 2g of cobalt phosphate nanopowder (sample 5) was added to 10g of epoxy resin emulsion and stirred evenly for 10min to obtain component A; 5g of fentanyl 287 was added to component A and stirred for 20min to obtain component B; the resulting mixture component B was defoamed in a vacuum laboratory; the mixture was sprayed onto the surface of plastic fiber using a spray gun with a spray pressure of 0.3MPa and a spray gun distance of 20cm; the sprayed plastic fiber was left to dry for 2 hours, and then placed in an oven at 100℃ for 10 hours to cure.
[0061] Example 5:
[0062] 2g of cobalt phosphate nanopowder (sample 6) was added to 7g of epoxy resin emulsion and stirred evenly for 10min to obtain component A; 5g of water-soluble polyamide was added to component A and stirred for 20min to obtain component B; the resulting mixture component B was defoamed in a vacuum laboratory; the mixture was sprayed onto the surface of plastic fiber using a spray gun with a spray pressure of 0.3MPa and a spray gun distance of 20cm; the sprayed plastic fiber was left to dry for 2 hours, and then placed in an oven at 100℃ for 10 hours to cure.
[0063] Example 6:
[0064] 2g of cobalt phosphate nanopowder (sample 7) was added to 8g of epoxy resin emulsion and stirred evenly for 10min to obtain component A; 3g of water-soluble polyamide was added to component A and stirred for 20min to obtain component B; the resulting mixture component B was defoamed in a vacuum laboratory; the mixture was sprayed onto the surface of plastic fiber using a spray gun with a spray pressure of 0.3MPa and a spray gun distance of 20cm; the sprayed plastic fiber was left to dry for 2 hours, and then placed in an oven at 60℃ for 6 hours for curing.
[0065] The components of Examples 1-6 described above are statistically analyzed as shown in the table below:
[0066]
[0067]
[0068] The embodiments described in the preceding paragraphs may be combined with one or more of the specifically described alternatives. In particular, the claimed embodiments may contain references to more than one other embodiment. The claimed embodiments may specify further limitations on the claimed subject matter.
[0069] Many variations can be made to the embodiments of the invention without departing from the scope of the invention. Such modifications are within the scope of the invention. The embodiments presented herein have been described in conjunction with specific examples, which are illustrative in all respects and not restrictive. Alternative embodiments and modifications will be apparent to those skilled in the art, but will not depart from the scope of the invention.
[0070] As can be seen from the foregoing, the present invention is well suited to achieving all the aforementioned objects and objectives, as well as other obvious and inherent advantages of the structure. It should be understood that certain features and sub-combinations are useful and can be used without reference to other features and sub-combinations. This is within the scope of the present invention.
[0071] Various aspects of the illustrative embodiments have been described using terminology commonly used by those skilled in the art to convey the essence of the work to others skilled in the art. However, it will be apparent to those skilled in the art that alternative embodiments can be implemented using only some of the described aspects. Specific figures, materials, and configurations are set forth for illustrative purposes to provide a thorough understanding of the illustrative embodiments. However, it will be apparent to those skilled in the art that alternative embodiments can be implemented without specific details. In other instances, well-known features have been omitted or simplified so as not to obscure the illustrative embodiments.
[0072] Various operations are described as multiple separate operations in a manner most conducive to understanding the illustrative embodiments; however, the order of description should not be construed as implying that these operations are necessarily sequentially related. In particular, these operations do not need to be performed in the order presented. Furthermore, describing operations as separate operations should not be construed as requiring that these operations must be performed independently and / or by separate entities. Similarly, describing entities and / or modules as separate modules should not be construed as requiring that modules be separate and / or perform separate operations. Operations, entities, data, and / or modules described in the various embodiments may be combined, broken down into more sub-parts, and / or omitted.
[0073] The phrase "in one embodiment" or "in an embodiment" is used repeatedly. This phrase does not usually refer to the same embodiment; however, it may refer to the same embodiment. The terms "comprising," "having," and "including" are synonymous unless the context otherwise specifies. The phrase "A / B" means "A or B." The phrase "A and / or B" means "(A), (B), or (A and B)." The phrase "at least one of A, B, and C" means "(A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C)."
Claims
1. A corrosion-resistant coating containing cobalt phosphate nanopowder, characterized in that, It includes 5-15 parts epoxy resin emulsion, 1-5 parts curing agent and 1-2 parts cobalt phosphate nanoparticles; The preparation of the cobalt phosphate nanopowder includes: Dissolve sodium dihydrogen phosphate dihydrate in water to form a sodium dihydrogen phosphate dihydrate solution; Hexamethylenetetramine is dissolved in an organic solvent to form a hexamethylenetetramine solution; A mixed solution of sodium dihydrogen phosphate dihydrate and hexamethylenetetramine was formed by mixing the two solutions. Cobalt nitrate hexahydrate was then added, and a hydrothermal solvothermal reaction was performed to obtain a suspension. After cooling, precipitation, centrifugation, washing, and drying, cobalt phosphate nanoparticles were obtained. The chemical reaction formula for the preparation of cobalt phosphate is as follows: 3Co(NO3)2+2NaH2PO4=Co3(PO4)2+2NaNO3+4HNO3 The pressure condition for the hydrothermal solvothermal reaction is 0.5 MPa; The hydrothermal solvothermal reaction was carried out at a temperature of 130℃ for 3 hours. The drying temperature for the hydrothermal solvothermal reaction was 60℃, and the time was 12h. Anhydrous ethanol is used as the organic solvent.
2. The corrosion-resistant coating containing cobalt phosphate nanopowder according to claim 1, characterized in that, It meets one or more of the following characteristics: The epoxy resin emulsion is 6 parts; The curing agent is 1 part; Two parts of cobalt phosphate nanopowder were used. The curing agent is selected from one or a combination of water-soluble polyamide, Amkorwyn 100, and Amkorwyn 287.
3. A method for preparing a corrosion-resistant coating containing cobalt phosphate nanopowder as described in claim 1, characterized in that, Includes the following steps: Add 1-2 parts of cobalt phosphate nanopowder to 5-15 parts of epoxy resin emulsion and stir to obtain component A; Add 1-5 parts of curing agent to component A and stir evenly to obtain component B; The mixture of component B was defoamed under vacuum to obtain a corrosion-resistant emulsion containing cobalt phosphate nanopowder; After the corrosion-resistant emulsion containing cobalt phosphate nanopowder is sprayed onto the substrate and dried, it is cured at 50-100℃ for 6-10 hours.
4. The method for preparing the corrosion-resistant coating according to claim 3, characterized in that, It meets one or more of the following characteristics: The epoxy resin emulsion is 6 parts; The curing agent is 1 part; Two parts of cobalt phosphate nanopowder were used. The curing agent is selected from one or a combination of water-soluble polyamide, Amkorwyn 100, and Amkorwyn 287.
5. The method for preparing the corrosion-resistant coating according to claim 3, characterized in that, The drying temperature of the corrosion-resistant emulsion sprayed with cobalt phosphate nanopowder after drying is 60℃, and the curing time is 6h.
6. The application of a corrosion-resistant coating containing cobalt phosphate nanopowder, characterized in that, The corrosion-resistant coating containing cobalt phosphate nanopowder as described in claim 1 or 2 is applied to the corrosion protection of the substrate.
7. The application according to claim 6, characterized in that, The substrate is a fiber material.