A-site doped c2s high-entropy ceramic thermal spray powder and a preparation method thereof

Abstract

The application belongs to the technical field of high-entropy ceramic materials, and more particularly relates to A-site doped C2S high-entropy ceramic thermal spraying powder and a preparation method thereof. 0.2 La 0.2 Na 0.2 Sr 0.2 Ba 0.2 )2SiO4.The application causes C2S lattice distortion effect by A-site high-entropy design of C2S high-entropy ceramics, and dopes five elements with similar chemical properties and similar ionic radii into the A-site lattice of C2S ceramics, so that the degree of confusion of C2S is increased, and the corrosion resistance of C2S ceramics is improved.

Description

Technical Field

[0001] This invention belongs to the field of high-entropy ceramic materials technology, and more specifically relates to an A-site doped C2S high-entropy ceramic thermal spraying powder and its preparation method. Background Technology

[0002] In the aluminum processing and aluminum alloy casting industry, rollers are core components in processes such as aluminum molten material conveying and casting. These rollers need to be immersed in or in contact with high-temperature molten aluminum at temperatures reaching up to 660°C for extended periods, operating in extremely harsh environments. With the rapid development of industries such as new energy vehicles, aerospace, and electronic information, the market demand for aluminum alloy products continues to grow, placing higher demands on the continuous and efficient operation of aluminum processing production lines. The service life and reliability of roller components directly affect the stable operation of the production line and production costs.

[0003] Currently, the industry mainly adopts the following technical solutions to address the corrosion problem of rollers in molten aluminum: First, rollers are directly manufactured using high-temperature resistant metal materials such as stainless steel and nickel-based alloys, utilizing the high-temperature strength and corrosion resistance of the metal materials themselves to resist the erosion of molten aluminum; second, conventional ceramic coatings (such as alumina and zirconium oxide coatings) are applied to the surface of the metal rollers, using the chemical inertness of the ceramic materials to isolate the direct contact between the molten aluminum and the metal substrate; third, dicalcium silicate (Ca2SiO4, or C2S) ceramic material is used as a thermal spray powder, sprayed onto the roller surface to form a protective coating, utilizing the high chemical stability and high-temperature resistance of C2S ceramics to delay the corrosion of the rollers by molten aluminum.

[0004] Each of the above solutions has its own advantages: the metal material solution has mature technology and good mechanical properties, which can meet the basic load-bearing and operation requirements of the roller; the conventional ceramic coating solution has a relatively simple preparation process and can improve the corrosion resistance of the roller surface to a certain extent; the C2S ceramic coating solution has higher chemical stability than conventional ceramic coating and exhibits relatively better corrosion resistance in the high-temperature aluminum liquid environment.

[0005] However, the aforementioned existing technologies all have significant shortcomings: after prolonged immersion in 660°C molten aluminum, metallic materials (such as stainless steel and nickel-based alloys) still undergo severe aluminum etching and alloying reactions, leading to gradual erosion and damage to the roller surface, resulting in limited corrosion resistance; after long-term service in a high-temperature molten aluminum environment, conventional ceramic coatings (such as alumina and zirconia coatings) experience interfacial reactions between the coating and the molten aluminum, reducing the coating's density and adhesion, leading to coating peeling and failure; even the relatively high-performance C2S ceramic coating, being a single-component ceramic with a stable lattice structure but low configuration entropy, allows aluminum atoms to diffuse and penetrate into the coating along grain boundaries and microscopic defects in the corrosive environment of molten aluminum, resulting in a high etching rate and insufficient protection life to meet the needs of continuous industrial production.

[0006] The aforementioned defects directly result in a short service life for the rollers when operating in molten aluminum, requiring frequent shutdowns for roller replacement, which severely affects the continuous operation efficiency of the aluminum processing production line. Frequent roller replacement not only increases equipment maintenance and spare parts consumption costs, but also causes production capacity losses due to downtime, pushing up the overall production cost of aluminum alloy products. In addition, corrosion products generated after the rollers are corroded by molten aluminum may also mix into the molten aluminum, affecting the purity and quality stability of aluminum alloy products.

[0007] As the aluminum processing industry develops towards high-end and intelligent directions, the continuous operating time and automation level of production lines are constantly increasing, placing higher demands on the service life and reliability of roller workpieces. Therefore, there is an urgent need to develop a new type of ceramic coating material with higher resistance to aluminum molten corrosion, fundamentally solving the corrosion problem of rollers in the high-temperature aluminum molten environment, and meeting the urgent needs of the aluminum processing industry for long-life, high-reliability roller workpieces. Summary of the Invention

[0008] The purpose of this invention is to provide an A-site doped C2S high-entropy ceramic thermal spray powder and its preparation method, so as to solve the problems existing in the prior art.

[0009] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is to provide an A-site doped C2S high-entropy ceramic thermal spray powder, wherein the chemical formula of the A-site doped C2S high-entropy ceramic thermal spray powder is: (Ca 0.2 La 0.2 Na 0.2 Sr 0.2 Ba 0.2 )2SiO4.

[0010] This invention designs high-entropy C2S ceramics at the A-site by incorporating five elements with similar chemical properties and ionic radii into the A-site lattice of the C2S ceramic in an equimolar ratio. This induces a C2S lattice distortion effect, increasing its disorder and improving the corrosion resistance of the C2S ceramic.

[0011] The second technical solution of the present invention provides a method for preparing the above-mentioned A-site doped C2S high-entropy ceramic thermal spray powder, the steps of which include: According to the stoichiometric ratio of the chemical formula, CaCO3, La2O3, Na2CO3, SrCO3, BaCO3 and SiO2 were weighed as raw materials, and the raw materials were mixed and ball-milled to obtain a mixed powder. The binder is mixed with the mixed powder, stirred evenly, and then granulated, sintered, and sieved to obtain the A-site doped C2S high-entropy ceramic thermal spray powder.

[0012] The method for preparing A-site doped C2S high-entropy ceramic thermal spray powder provided by the present invention involves mixing raw materials by ball milling and then preparing A-site doped C2S high-entropy ceramic thermal spray powder by high-temperature sintering. The sintering process does not require specific atmosphere control and does not require the addition of sintering aids. The process is short, the preparation cost is low, and the preparation efficiency is high.

[0013] Furthermore, in the mixed ball milling process, ethanol and zirconium oxide are used as the ball milling media, wherein the mass ratio of ethanol, zirconium oxide and the raw material is 5:1:5.

[0014] Furthermore, the ball milling process is carried out at a speed of 300 rpm for 12 to 24 hours.

[0015] Furthermore, the adhesive includes gum arabic.

[0016] Furthermore, the mass ratio of the binder to the mixed powder is (2-5):100.

[0017] Furthermore, the stirring time is 30 minutes.

[0018] Furthermore, the granulation is performed using a spray drying granulation method.

[0019] Optionally, the parameters of the spray drying granulation method include: an inlet air temperature of 280~300℃, an outlet air temperature of 100~150℃, and an atomization speed of 16800rpm.

[0020] Furthermore, the sintering process includes heating to 1100~1200℃ at a heating rate of 6℃ / min and holding at that temperature for 3~4 hours.

[0021] Furthermore, after sintering is completed, a furnace cooling step is also included.

[0022] Furthermore, the mesh size of the sieve used for sieving is 180-270 mesh.

[0023] Optionally, the sieving process involves passing the material through a 180-mesh sieve and a 270-mesh sieve sequentially.

[0024] The A-site doped C2S ceramic thermal spray powder provided by this invention has excellent wear and corrosion resistance. When sprayed onto the surface of metal workpieces (such as rollers), it can significantly reduce the etching rate of the metal workpieces immersed in molten aluminum and improve the corrosion resistance of the metal workpieces.

[0025] The present invention discloses the following technical effects: This invention effectively improves the corrosion resistance of C2S (dicalcium silicate) ceramics by designing the A-sites with high entropy. The preparation process is simple, requiring no special atmosphere sintering, and features short sintering time, simple process, low production cost, and high efficiency. Furthermore, no sintering aids are needed during the preparation of C2S ceramic thermal spray powder.

[0026] The A-site doped C2S high-entropy ceramic thermal spray powder provided by this invention can significantly reduce the etching rate and improve the corrosion resistance of metal workpieces (such as rollers) after being sprayed onto their surfaces. Compared with metal workpieces sprayed with C2S thermal spray powder, the etching rate is significantly reduced. Attached Figure Description

[0027] 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 The image shows the XRD pattern of the A-site doped C2S ceramic thermal spray powder prepared in Example 1.

[0028] Figure 2 The image shows an SEM image of the A-site doped C2S ceramic thermal spray powder prepared in Example 1.

[0029] Figure 3 Etching rate diagram of the rollers used to spray ceramic thermal spray powder of Examples 1-3 and Comparative Example 1. Detailed Implementation

[0030] 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.

[0031] 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. Any stated value or intermediate value within a stated range, as well as each smaller range between 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.

[0032] 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.

[0033] 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 apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0034] 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.

[0035] Unless otherwise specified, all raw materials and reagents involved in the specific embodiments of this invention are commercially available products.

[0036] Unless otherwise specified, room temperature and normal temperature in the specific embodiments of this invention refer to 20-30℃.

[0037] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0038] Example 1 The preparation steps of A-site doped C2S ceramic thermal spray powder include: S1, according to (Ca) 0.2 La 0.2 Na 0.2 Sr 0.2 Ba 0.2 The stoichiometric ratio of CaCO3, La2O3, Na2CO3, SrCO3, BaCO3, and SiO2 powders was weighed and used as raw materials for ball milling.

[0039] S2. Place the ball milling raw material from step S1 into a ball mill and ball mill it for 12 hours at a mass ratio of anhydrous ethanol, zirconia balls and ball milling raw material of 5:1:5. The ball mill speed is 300 rpm to obtain mixed powder.

[0040] S3. Add gum arabic to the obtained mixed powder and stir for 30 minutes. The mass ratio of gum arabic to mixed powder is 5:100 to obtain ceramic slurry.

[0041] S4. The obtained ceramic slurry is placed in a high-speed centrifugal spray drying tower for granulation to obtain ceramic particles. The inlet air temperature of the drying tower is 280℃, the outlet air temperature of the drying tower is 130℃, and the atomization speed of the high-speed centrifugal spray drying tower during granulation is 16800 rpm.

[0042] S5. Place the obtained ceramic particles in a crucible, put the crucible into a muffle furnace, heat it to 1100℃ at a heating rate of 6℃ / min, keep it in the muffle furnace for 3 hours, and then cool it to room temperature with the furnace. Then pass the sintered ceramic particles through 180 mesh and 270 mesh sieves in sequence to obtain A-site doped C2S ceramic thermal spray powder.

[0043] Example 2 The preparation steps of A-site doped C2S ceramic thermal spray powder include: S1, according to (Ca) 0.2 La 0.2 Na 0.2 Sr 0.2 Ba 0.2 The stoichiometric ratio of CaCO3, La2O3, Na2CO3, SrCO3, BaCO3, and SiO2 powders was weighed and used as raw materials for ball milling.

[0044] S2. Place the ball milling raw material from step S1 into a ball mill and ball mill it for 12 hours at a mass ratio of anhydrous ethanol, zirconia balls and ball milling raw material of 5:1:5. The ball mill speed is 300 rpm to obtain mixed powder.

[0045] S3. Add gum arabic to the obtained mixed powder and stir for 30 minutes. The mass ratio of gum arabic to mixed powder is 2:100 to obtain ceramic slurry.

[0046] S4. The obtained ceramic slurry is placed in a high-speed centrifugal spray drying tower for granulation to obtain ceramic particles. The inlet air temperature of the drying tower is 290℃, the outlet air temperature of the drying tower is 125℃, and the atomization speed of the high-speed centrifugal spray drying tower during granulation is 16800 rpm.

[0047] S5. Place the obtained ceramic particles in a crucible, put the crucible into a muffle furnace, heat it to 1130℃ at a heating rate of 6℃ / min, keep it in the muffle furnace for 4 hours, and then cool it to room temperature with the furnace. Then pass the sintered ceramic particles through 180 mesh and 270 mesh sieves in sequence to obtain A-site doped C2S ceramic thermal spray powder.

[0048] Example 3 The preparation steps of A-site doped C2S ceramic thermal spray powder include: S1, according to (Ca) 0.2 La 0.2Na 0.2 Sr 0.2 Ba 0.2 The stoichiometric ratio of CaCO3, La2O3, Na2CO3, SrCO3, BaCO3, and SiO2 powders was weighed and used as raw materials for ball milling.

[0049] S2. Place the ball milling raw material from step S1 into a ball mill and ball mill it for 12 hours at a mass ratio of anhydrous ethanol, zirconia balls and ball milling raw material of 5:1:5. The ball mill speed is 300 rpm to obtain mixed powder.

[0050] S3. Add gum arabic to the obtained mixed powder and stir for 30 minutes. The mass ratio of gum arabic to mixed powder is 5:100 to obtain ceramic slurry.

[0051] S4. The obtained ceramic slurry is placed in a high-speed centrifugal spray drying tower for granulation to obtain ceramic particles. The inlet air temperature of the drying tower is 300℃, the outlet air temperature of the drying tower is 145℃, and the atomization speed of the high-speed centrifugal spray drying tower during granulation is 16800 rpm.

[0052] S5. Place the obtained ceramic particles in a crucible, put the crucible into a muffle furnace, heat it to 1200℃ at a heating rate of 6℃ / min, hold it in the muffle furnace for 3.8h, and then cool it to room temperature with the furnace. Then pass the sintered ceramic particles through 180 mesh and 270 mesh sieves in sequence to obtain A-site doped C2S ceramic thermal spray powder.

[0053] Comparative Example 1 A C2S ceramic thermal spray powder, with the chemical formula Ca2SiO4, is prepared as follows: S1. Weigh CaCO3 and SiO2 powders according to the stoichiometric ratio of Ca2SiO4; put the powders into a ball mill and ball mill them for 12 hours at a mass ratio of anhydrous ethanol, zirconia balls and ball milling material (i.e., the powders) of 5:1:5, and the ball mill speed is 300 rpm to obtain a mixed powder; then add gum arabic to the obtained mixed powder and stir for 30 minutes at a mass ratio of gum arabic to mixed powder of 5:100 to obtain a stirred ceramic slurry.

[0054] S2. The stirred ceramic slurry obtained in step S1 is placed in a high-speed centrifugal spray drying tower for granulation. The inlet air temperature of the drying tower is 280℃, the outlet air temperature of the drying tower is 130℃, and the atomization speed of the high-speed centrifugal spray drying tower during granulation is 16800rpm to obtain ceramic particles.

[0055] S3. Place the ceramic particles obtained in step S2 into a crucible, put the crucible into a muffle furnace, heat it to 1200℃ at a heating rate of 6℃ / min, keep it in the muffle furnace for 3 hours, and then cool it to room temperature with the furnace. Then pass the sintered ceramic particles through 180 mesh and 270 mesh sieves in sequence to obtain C2S ceramic thermal spray powder.

[0056] Test case Figure 1 The image shows the XRD pattern of the A-site doped C2S ceramic thermal spray powder prepared in Example 1. As can be seen from the image, the A-site doped C2S ceramic thermal spray powder prepared in Example 1 ((Ca...)... 0.2 La 0.2 Na 0.2 Sr 0.2 Ba 0.2 (2SiO4) has a single-phase perovskite structure with only extremely small impurity peaks.

[0057] Figure 2 This is a SEM image of the A-site doped C2S ceramic thermal spray powder prepared in Example 1. As can be seen from the image, the A-site doped C2S ceramic thermal spray powder prepared in Example 1 ((Ca...)... 0.2 La 0.2 Na 0.2 Sr 0.2 Ba 0.2 2SiO4 has excellent sphericity.

[0058] The ceramic thermal spray powders prepared in the examples and comparative examples were sprayed onto the surface of rollers, and performance comparison tests were conducted. The steps are as follows: The (Ca) prepared in Examples 1-3 were respectively 0.2 La 0.2 Na 0.2 Sr 0.2 Ba 0.2 High-entropy C2S ceramic thermal spray powder prepared in Examples 1-3 or C2S ceramic thermal spray powder prepared in Comparative Example 1 were sprayed onto the surface of a roller, and then the etching rate of the sprayed roller was tested. The specific spraying and testing methods were as follows: The high-entropy C2S ceramic thermal spray powder prepared in Examples 1-3 or C2S ceramic thermal spray powder prepared in Comparative Example 1 were sprayed onto the surface of the roller using a plasma device to obtain a coating with a thickness of 400 μm. Then, the sprayed roller was etched using molten aluminum at 660℃.

[0059] Figure 3 The graph shows the etching rate of the rollers sprayed with the ceramic thermal spray powders of Examples 1-3 and Comparative Example 1. As can be seen from the graph, the rollers sprayed with the (Ca) powder prepared in Example 1... 0.2 La 0.2 Na 0.2 Sr 0.2 Ba0.2 The roller coated with 2SiO4 ceramic thermal spray powder showed a significantly lower etching rate compared to the roller coated with C2S ceramic thermal spray powder prepared in Comparative Example 1, with a reduction of 2.8 nm / min. This demonstrates that the (Ca2S) ceramic thermal spray powder prepared in this invention... 0.2 La 0.2 Na 0.2 Sr 0.2 Ba 0.2 )2SiO4 ceramic thermal spray powder has excellent corrosion resistance and can significantly improve the corrosion resistance of rollers.

[0060] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0061] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An A-site doped C2S high-entropy ceramic thermal spray powder, characterized in that, The chemical formula of the A-site doped C2S high-entropy ceramic thermal spray powder is: (Ca 0.2 La 0.2 Na 0.2 Sr 0.2 Ba 0.2 )2SiO4.

2. A method for preparing A-site doped C2S high-entropy ceramic thermal spray powder according to claim 1, characterized in that the step... include: According to the stoichiometric ratio of the chemical formula, CaCO3, La2O3, Na2CO3, SrCO3, BaCO3 and SiO2 were weighed as raw materials, and the raw materials were mixed and ball-milled to obtain a mixed powder. The binder is mixed with the mixed powder, stirred evenly, and then granulated, sintered, and sieved to obtain the A-site doped C2S high-entropy ceramic thermal spray powder.

3. The preparation method according to claim 2, characterized in that, In the mixed ball milling process, ethanol and zirconium oxide are used as the ball milling media, wherein the mass ratio of ethanol, zirconium oxide and the raw material is 5:1:

5.

4. The preparation method according to claim 2, characterized in that, The ball milling process is performed at a speed of 300 rpm for 12 to 24 hours.

5. The preparation method according to claim 2, characterized in that, The adhesive includes gum arabic; And / or, the mass ratio of the binder to the mixed powder is (2-5):

100.

6. The preparation method according to claim 2, characterized in that, The stirring time is 30 minutes.

7. The preparation method according to claim 2, characterized in that, The granulation is performed using spray drying granulation method; And / or, the sintering includes heating to 1100~1200℃ at a heating rate of 6℃ / min and holding at that temperature for 3~4h; And / or, after the sintering is completed, the process further includes a furnace cooling step; And / or, the mesh size of the sieve used for sieving is 180~270 mesh.

8. The preparation method according to claim 7, characterized in that, The parameters of the spray drying granulation method include: inlet air temperature of 280~300℃, outlet air temperature of 100~150℃, and atomization speed of 16800rpm. And / or, the sieving is performed by passing the material through a 180-mesh sieve and a 270-mesh sieve in sequence.

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