A b-site doped manganese ferrite ceramic thermal spray powder and method of making

Abstract

The application provides a B-site doped manganese ferrite ceramic thermal spraying powder and a preparation method thereof, and belongs to the technical field of thermal spraying materials. 1 / 3 Co 1 / 3 Ni 1 / 3 )2O4, by introducing equimolar Fe, Co and Ni into the B site of manganese ferrite, the design of medium entropy is realized, the lattice distortion is caused, and the structural disorder degree is improved, so that the thermal spraying performance and electrochemical activity are optimized. The powder is prepared from NiO, Fe2O3, Co3O4 and MnO2 as raw materials, ball milling, adding Arabic gum granulation, sintering at 900-950 DEG C in air for 3-4 hours, and then screening to obtain 80-100 mesh thermal spraying powder. The method is simple in process, low in cost and high in efficiency, the medium entropy ceramic powder prepared by the method is sprayed on the optical net nickel net as the alkaline electrolytic water anode, the small chamber voltage can be effectively reduced by about 0.04 V, and good application prospect is shown.

Description

Technical Field

[0001] This invention belongs to the field of thermal spraying materials technology, and particularly relates to a B-site doped manganese ferrite ceramic thermal spraying powder and its preparation method. Background Technology

[0002] Hydrogen production technology, as a core link in the upstream industrial chain of hydrogen energy, is ushering in unprecedented development opportunities. Among the many hydrogen production pathways, water electrolysis has attracted much attention due to its unique advantages: it can effectively utilize the waste electricity or waste heat generated by renewable energy sources such as wind and solar power as a driving force, achieving truly sustainable and pollution-free hydrogen production; the produced hydrogen has high purity, typically reaching over 99.9%, and produces no harmful byproducts, and under ideal conditions, it can even achieve zero carbon emissions throughout its entire life cycle. Therefore, from the perspectives of environmental benefits, energy efficiency, and system applicability, water electrolysis demonstrates significant technological superiority and is considered a key pathway for the large-scale production of green hydrogen. A typical water electrolysis reaction system consists of three parts: a cathode, an anode, and an electrolyte. The cathode undergoes the hydrogen evolution reaction (HER), while the anode undergoes the more kinetic oxygen evolution reaction (OER). Since the OER involves a complex four-electron transfer process, its high overpotential and slow rate become a bottleneck restricting the overall electrolysis efficiency; therefore, the development of high-performance anode materials is crucial.

[0003] Nickel ferrite ceramics, due to their inverse spinel crystal structure, good chemical stability, excellent electronic conductivity, and relatively low cost, have long been extensively studied and used as anolyte catalysts for alkaline water electrolysis. Importantly, nickel ferrite's performance position is close to the theoretical activity peak in the "volcano-shaped" regular curve describing the relationship between OER catalytic activity and adsorption energy, demonstrating significant application potential. In recent years, a new class of high-performance ceramics—medium-entropy ceramics—has emerged in materials science. These ceramics form highly disordered solid solutions by doping three to four main metal elements in near-equimolar proportions at the same lattice site, thereby inducing significant lattice distortion and hysteresis diffusion effects, potentially synergistically improving the catalytic activity, structural stability, and thermodynamic properties of the material. However, although the medium-entropy design concept has achieved breakthroughs in alloys and some oxide systems, no research has yet applied this cutting-edge strategy to the B-site medium-entropy design of manganese ferrite ceramics. This technological gap not only limits further breakthroughs in the performance of manganese ferrite-based anode materials but also provides an important innovative entry point and broad development space for this invention.

[0004] Therefore, there is an urgent need to provide a manganese ferrite ceramic thermal spray powder based on entropy design at the B site and its preparation method, so as to give full play to the synergistic effect of lattice distortion and components, improve its catalytic activity and engineering applicability as an anode material for water electrolysis, and thus reduce the voltage of the electrolysis chamber and improve hydrogen production efficiency. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a B-site doped manganese ferrite ceramic thermal spraying powder and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A B-site doped manganese ferrite ceramic thermal spray powder has a medium-entropy inverse spinel structure, in which Fe, Co and Ni metal elements occupy the B sites in the manganese ferrite lattice in an equimolar ratio.

[0007] Beneficial Effects: While traditional nickel ferrite exhibits good intrinsic OER (oxygen evolution reaction) activity, its performance is limited by the electronic structure and surface adsorption energy of the single B-site metal ion. This invention employs a medium-entropy strategy, co-doping Fe, Co, and Ni in equimolar proportions into the B-site lattice to form a high configurational entropy stable anti-spinel solid solution. This design induces significant lattice distortion effects and local electronic structure redistribution. The synergistic effect of multiple principal elements enhances charge transfer capability and surface active site density, thereby significantly improving intrinsic catalytic activity.

[0008] Optionally, the chemical formula of the B-site doped manganese ferrite ceramic thermal spray powder is Mn(Fe) 1 / 3 Co 1 / 3 Ni 1 / 3 )2O4.

[0009] The preparation method of the above-mentioned B-site doped manganese ferrite ceramic thermal spray powder includes the following steps: (a) A mixture of NiO, Fe2O3, Co3O4 and MnO2 powders was used as raw material; (b) Mix the above raw materials, ball milling media and dispersant, and ball mill to obtain a homogenate; (c) Add a binder to the slurry, stir well, and then perform spray granulation; (d) The obtained particles were sintered in an air atmosphere and then sieved to obtain the target product, namely B-site doped manganese ferrite ceramic thermal spray powder.

[0010] Beneficial Effects: This invention uses conventional oxides (NiO, Fe2O3, Co3O4, and MnO2) as starting materials and completes powder synthesis through a fully atmospheric pressure process involving ball milling, spray granulation, and air sintering. The entire process requires no inert or reducing atmosphere protection and does not rely on expensive sintering aids, significantly reducing equipment requirements and energy consumption. Simultaneously, spray granulation imparts good sphericity and flowability to the powder, meeting the requirements of thermal spraying for powder morphology and particle size distribution (80-100 mesh), ensuring coating density and adhesion. This process is short, highly repeatable, and uses readily available raw materials, possessing potential for industrial scale-up.

[0011] Optionally, the milling media are zirconia balls; The dispersant is anhydrous ethanol.

[0012] Furthermore, the mass ratio of the zirconium oxide balls, raw materials, and anhydrous ethanol is 5:1:5.

[0013] Optionally, the ball mill is operated at a speed of 300 rpm for 12 to 24 hours.

[0014] Optionally, the mass ratio of the binder to the slurry is 1:10, and the stirring time is 30 minutes.

[0015] Furthermore, the adhesive is gum arabic.

[0016] Optionally, the inlet air temperature of the spray granulation is 250-280℃, the outlet air temperature is 100-150℃, and the atomization speed is 280 Hz.

[0017] Optionally, the sintering conditions are as follows: heating to 900-950°C at a rate of 6°C / min, holding at that temperature for 3-4 hours, and then cooling to room temperature with the furnace.

[0018] Furthermore, the sintering temperature is 900℃.

[0019] Optionally, the sieving process uses an 80-100 mesh sieve.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects: The B-site doped manganese ferrite medium-entropy ceramic thermal spraying powder and its preparation method provided by this invention have significant process and performance advantages. Specifically: First, its preparation process is highly simplified. The entire process only requires conventional oxide raw materials. The target product can be obtained by ball milling, spray granulation and sintering in an air atmosphere. It does not require an inert or reducing protective atmosphere, nor does it require expensive or complex special equipment. Sintering can be completed with just an ordinary muffle furnace, which greatly reduces equipment investment and energy consumption. At the same time, the entire process is short, easy to operate and has good repeatability, and has good scalability and industrial application prospects.

[0021] Secondly, no sintering aids are required during the material synthesis process, which not only effectively avoids interference from external impurities on the purity and electrochemical performance of the ceramic phase, but also further simplifies the formulation system and improves the intrinsic stability and consistency of the material. More importantly, the obtained Mn(Fe) 1 / 3 Co 1 / 3 Ni 1 / 3The 2O4 medium-entropy ceramic thermal spray powder exhibits excellent spraying adaptability and electrocatalytic activity. When thermally sprayed onto the surface of a nickel mesh as an anode material for alkaline water electrolysis to produce hydrogen, it significantly improves the oxygen evolution reaction (OER) efficiency under typical industrial conditions such as 85℃ and 1.2 MPa. Experimental measurements show that the chamber voltage can be stably reduced by approximately 0.04-0.05 V. This performance improvement directly translates into a reduction in system energy consumption, demonstrating significant economic value and application potential in large-scale green hydrogen production.

[0022] In summary, this invention achieves a balance between low cost and high efficiency in preparation, while organically unifying material structure innovation and electrochemical performance optimization, providing a practical new path for the development of high-performance water electrolysis anode materials. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 Mn(Fe) prepared in Example 1 1 / 3 Co 1 / 3 Ni 1 / 3 XRD pattern of entropy-containing ceramic powder in 2O4; Figure 2 Mn(Fe) prepared in Example 1 1 / 3 Co 1 / 3 Ni 1 / 3 SEM image of entropy-containing ceramic powder in 2O4; Figure 3 Mn(Fe) prepared according to Examples 1-3 respectively 1 / 3 Co 1 / 3 Ni 1 / 3 Voltage diagram of a chamber for hydrogen production by electrolysis of water using 2O4 medium-entropy ceramic thermal spray powder coated nickel mesh and pure nickel mesh as anodes. Detailed Implementation

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0028] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0029] Unless otherwise specified, "room temperature" in this invention refers to 20-30℃.

[0030] Unless otherwise specified, the term "parts" in this invention refers to parts by weight.

[0031] All raw materials used in this invention were purchased from the market.

[0032] The technical solution of the present invention will be further illustrated by the following embodiments.

[0033] Example 1 A method for preparing B-site doped medium-entropy manganese ferrite ceramic spraying powder, the specific steps of which are as follows: (1) According to Mn(Fe 1 / 3 Co 1 / 3 Ni 1 / 3 Weigh Fe2O3, NiO, Co3O4, and MnO2 powders according to their stoichiometric ratio. Place the powders into a ball mill and mix them for 12 hours at a mass ratio of 5:5:1 (zirconia balls, anhydrous ethanol, and grinding media (the powders)). The ball mill speed is 300 rpm to obtain a ceramic slurry. Then, add gum arabic to the obtained ceramic slurry and stir for 30 minutes at a mass ratio of 10:100 (gum arabic to ceramic slurry) to obtain a stirred ceramic slurry.

[0034] (2) The stirred ceramic slurry obtained in step (1) is placed in a high-speed centrifugal spray drying tower for granulation. The inlet air temperature of the drying tower is 260℃ and the outlet air temperature of the drying tower is 130℃. The atomization speed of the high-speed centrifugal spray drying tower during granulation is 280Hz, and ceramic particles are obtained.

[0035] (3) Place the ceramic particles obtained in step (2) into a crucible, place the crucible into a muffle furnace, heat it to 900°C at a heating rate of 6°C / min, hold it in the muffle furnace for 3 hours, then cool it to room temperature with the furnace, and then pass the sintered powder through an 80-mesh sieve to obtain B-site doped medium-entropy manganese ferrite ceramic spray powder (Mn(Fe 1 / 3 Co 1 / 3 Ni 1 / 3 (2O4 medium entropy ceramic powder).

[0036] Example 2 A method for preparing B-site doped medium-entropy manganese ferrite ceramic spraying powder, the specific steps of which are as follows: (1) According to Mn(Fe 1 / 3 Co 1 / 3 Ni 1 / 3 NiO, Fe2O3, Co3O4, and MnO2 powders were weighed according to the stoichiometric ratio. The powders were placed in a ball mill and ball-milled for 12 hours at a mass ratio of 5:5:1 for zirconium oxide balls, anhydrous ethanol, and the grinding media (the powders). The ball mill speed was 300 rpm to obtain a ceramic slurry. Then, gum arabic was added to the obtained ceramic slurry and stirred for 30 minutes at a mass ratio of 10:100 for gum arabic to ceramic slurry to obtain a stirred ceramic slurry.

[0037] (2) The ceramic slurry obtained in step (1) is placed in a high-speed centrifugal spray drying tower for granulation. The inlet temperature of the drying tower is 270°C and the outlet temperature is 125°C. The atomization speed of the high-speed centrifugal spray drying tower is 280 Hz during granulation to obtain ceramic particles.

[0038] (3) Place the ceramic particles obtained in step (2) into a crucible, place the crucible into a muffle furnace, heat it to 930°C at a heating rate of 6°C / min, hold it in the muffle furnace for 3 hours, then cool it to room temperature with the furnace, and then pass the sintered powder through a 100-mesh sieve to obtain B-site doped medium-entropy manganese ferrite ceramic spray powder (Mn(Fe 1 / 3 Co 1 / 3 Ni 1 / 3 (2O4 medium entropy ceramic powder).

[0039] Example 3 A method for preparing B-site doped medium-entropy manganese ferrite ceramic spraying powder, the specific steps of which are as follows: (1) According to Mn(Fe 1 / 3 Co 1 / 3 Ni 1 / 3 Weigh NiO, Fe2O3, Co3O4, and MnO2 powders according to the stoichiometric ratio in the chemical formula 2O4. Place the powders into a ball mill and ball mill them for 12 hours at a mass ratio of 5:5:1 for zirconium oxide balls, anhydrous ethanol, and the grinding media (the powders). The ball mill speed is 300 rpm to obtain a ceramic slurry. Then, add gum arabic to the obtained ceramic slurry and stir for 30 minutes at a mass ratio of 10:100 for the gum arabic to the ceramic slurry to obtain a stirred ceramic slurry.

[0040] (2) The ceramic slurry obtained in step (1) is placed in a high-speed centrifugal spray drying tower for granulation. The inlet temperature of the drying tower is 280℃ and the outlet temperature of the drying tower is 145℃. The atomization speed of the high-speed centrifugal spray drying tower during granulation is 280Hz, and ceramic particles are obtained.

[0041] (3) Place the ceramic particles obtained in step (2) into a crucible, place the crucible into a muffle furnace, heat it to 950°C at a heating rate of 6°C / min, keep it in the muffle furnace for 3.8 hours, then cool it to room temperature with the furnace, and then pass the sintered powder through a 100-mesh sieve to obtain B-site doped medium-entropy manganese ferrite ceramic spray powder.

[0042] Figure 1 Mn(Fe) prepared in Example 1 1 / 3 Co 1 / 3 Ni 1 / 3 XRD pattern of medium-entropy ceramic powder of MnFe2O4. As can be seen from the figure, the medium-entropy ceramic powder prepared in Example 1 has a single anti-spinel phase structure. The position of the main diffraction peak is highly consistent with that of standard MnFe2O4. No obvious diffraction peaks of impurity phases such as NiO, Fe2O3, Co3O4 and MnO2 were observed. This indicates that the material has successfully formed a highly uniform single-phase medium-entropy solid solution, which confirms the effectiveness of the B-site ternary equimolar doping strategy and the rationality of the sintering process.

[0043] Figure 2 Mn(Fe) prepared in Example 1 1 / 3 Co 1 / 3 Ni 1 / 3SEM images of the 2O4 medium-entropy ceramic powder show that the powder particles are nearly spherical with a relatively uniform particle size distribution, mainly concentrated between 20-60 μm, which meets the particle size adaptability requirements of thermal spraying processes. The particle surface has abundant microporous structures and rough textures, which are derived from the "hollow-porous" morphology formed by the rapid drying of droplets during spray granulation, which is conducive to achieving good melt spreading and interlayer bonding during thermal spraying. At the same time, there is no obvious agglomeration or adhesion between particles, and the flowability is good, indicating that the spray granulation process effectively controls the loose density and packing characteristics of the powder. These morphological characteristics not only ensure the stable delivery of powder during the powder feeding process, but also help to improve the density, bonding strength and electrochemical active surface area of ​​the sprayed coating, laying a good physical foundation for its subsequent application as a high-performance water electrolysis anode material.

[0044] The Mn(Fe) prepared in Examples 1-3 were respectively 1 / 3 Co 1 / 3 Ni 1 / 3 Manganese ferrite-coated nickel mesh was obtained by spraying medium-entropy ceramic powder (2O4) onto a nickel mesh. Hydrogen production via water electrolysis was performed using this manganese ferrite-coated nickel mesh as the anode and a nickel mesh as the cathode (anode: manganese ferrite-coated nickel mesh + cathode: optical mesh). Simultaneously, a pure nickel mesh without medium-entropy ceramic powder coating was used as a control (anode: optical mesh + cathode: optical mesh). The chamber voltage was measured at a pressure of 1.2 MPa and an alkaline solution temperature of 85°C. The test results are shown below. Figure 3 .

[0045] Figure 3 Mn(Fe) prepared according to Examples 1-3 respectively 1 / 3 Co 1 / 3 Ni 1 / 3 The figure shows the chamber voltage of the three medium-entropy ceramic-coated anodes (Mn(Fe2O4)2O4) using nickel mesh and pure nickel mesh as anodes for water electrolysis to produce hydrogen. As can be seen from the figure, under the same electrolysis conditions, the chamber voltage of the three medium-entropy ceramic-coated anodes prepared according to this invention is significantly lower than that of the uncoated pure nickel mesh anode. Specifically, the average chamber voltage of Examples 1-3 decreased by 0.05, 0.04, and 0.04 V, respectively, and the performance differences among the three were small, indicating that the medium-entropy ceramic powder still has good reproducibility and stability under different batches or fine-tuning processes. This voltage reduction directly reflects the performance of Mn(Fe2O4)2O4. 1 / 3 Co 1 / 3 Ni 1 / 3 The 2O4 medium-entropy ceramic coating effectively enhances the catalytic activity of the oxygen evolution reaction (OER) at the anode and reduces electrode polarization, thereby improving electrolysis efficiency. The results fully demonstrate that the medium-entropy ceramic thermal spray powder provided by this invention possesses excellent application potential and energy-saving advantages in the field of alkaline water electrolysis for hydrogen production.

[0046] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A B-site-doped manganese ferrite ceramic thermal spray powder, characterized in that, It has a medium-entropy anti-spinel structure, with Fe, Co and Ni occupying the B sites in the manganese ferrite lattice in an equimolar ratio.

2. The B-site-doped manganese ferrite ceramic thermal spray powder according to claim 1, characterized in that, The chemical formula of the B-site doped manganese ferrite ceramic thermal spray powder is Mn(Fe) 1 / 3 Co 1 / 3 Ni 1 / 3 )2O4.

3. A method for preparing B-site doped manganese ferrite ceramic thermal spray powder as described in claim 1 or 2, characterized in that, Includes the following steps: NiO, Fe2O3, Co3O4 and MnO2 powders are mixed as raw materials; The raw materials, milling media, and dispersant are mixed and ball-milled to obtain a homogenate. Add a binder to the slurry, stir well, and then perform spray granulation; The obtained particles were sintered in an air atmosphere and then sieved to obtain the target product, namely the B-site doped manganese ferrite ceramic thermal spray powder.

4. The method for preparing B-site doped manganese ferrite ceramic thermal spray powder according to claim 3, characterized in that, The mass ratio of the binder to the homogenate is 1:10, and the stirring time is 30 minutes.

5. The method for preparing B-site doped manganese ferrite ceramic thermal spray powder according to claim 3, characterized in that, The inlet air temperature of the spray granulation is 250-280℃, the outlet air temperature is 100-150℃, and the atomization speed is 280 Hz.

6. The method for preparing B-site doped manganese ferrite ceramic thermal spray powder according to claim 3, characterized in that, The sintering process involves heating the furnace to 900–950°C at a rate of 6°C / min, holding the temperature for 3–4 hours, and then cooling the furnace to room temperature.

7. The method for preparing B-site doped manganese ferrite ceramic thermal spray powder according to claim 6, characterized in that, The sintering temperature is 900℃.

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