Nano-copper antibacterial steel for regulating and controlling slow release of copper precipitated phase based on rare earth elements and preparation method of nano-copper antibacterial steel

Abstract

The invention discloses nano-copper antibacterial steel for regulating and controlling slow release of a copper precipitated phase based on rare earth elements and a preparation method of the nano-copper antibacterial steel, and relates to the technical field of nano-copper antibacterial steel. The nano-copper antibacterial steel provided by the invention comprises the following chemical components in percentage by mass: 0.06 to 0.12 percent of C, 0.6 to 1.2 percent of Mn, 0.15 to 0.60 percent of Si, 0.6 to 2.0 percent of Cu, 0.005 to 0.030 percent of Ce and the balance of Fe and inevitable impurity elements. Rare earth elements are introduced into the nano-copper antibacterial steel, the form and size of a copper precipitation phase are accurately regulated and controlled, conversion of the copper precipitation phase to an FCC-Cu structure is inhibited, the copper precipitation phase is stabilized in a 9R-Cu metastable structure, and the nano-copper antibacterial steel has the high specific surface area and rich interface characteristics; and the stability of a copper precipitated phase in the nano-copper antibacterial steel and the capability of slowly releasing Cu < 2 + > ions can be improved, so that the lasting time of the antibacterial property is remarkably prolonged.

Description

Technical Field

[0001] This invention relates to the field of nano-copper antibacterial steel technology, and particularly to nano-copper antibacterial steel technology based on the controlled release of copper precipitates using rare earth elements. Background Technology

[0002] Copper (Cu) is a natural antibacterial element because it can release copper ions (Cu). 2+ Copper, by interacting with bacterial cell membranes and inhibiting bacterial growth, is widely used in the research and development of antibacterial materials. The applications of copper-based antibacterial materials cover multiple fields, including medical devices, kitchenware, and building coatings. In these materials, copper exerts its antibacterial effect by directly releasing copper ions or forming copper oxide films, showing particularly significant effects in environmental hygiene and antibacterial coatings.

[0003] However, existing copper-based antibacterial materials face a common problem: their antibacterial performance rapidly declines over time. This decline is mainly due to changes in the structure of the copper precipitate phase, an increase in the particle size of the precipitate, and an excessively rapid release rate of copper ions. For example, copper precipitates typically coarsen and aggregate with prolonged use, leading to a gradual decrease in their surface area and thus reducing the duration of the antibacterial reaction. Therefore, how to prolong the antibacterial efficacy while maintaining strong initial antibacterial activity has become a major challenge in current research on copper-based antibacterial materials.

[0004] To address this issue, researchers have recently focused on the introduction of rare earth elements (such as Ce) to explore their potential in regulating copper precipitation behavior and improving antibacterial effects. Ce not only improves the corrosion resistance of materials but also influences their microstructure, particularly by regulating the morphology and distribution of the precipitated phase, thereby enhancing copper stability and thus its antibacterial effect. However, current research primarily focuses on improving antibacterial effects or corrosion resistance, without delving into the specific crystal structure of the copper precipitate, and especially without systematically exploring how to optimize the slow-release properties of copper ions through precipitate structure regulation to extend antibacterial lifespan.

[0005] For example, the paper "Investigation of the combination of Cu and Ce effects on enhancing antibacterial and biocorrosion resistance performances of 2205 duplex stainless steel" (Guo-Teng Zhang, Xin-Xin Wei, Zi-Chen Hu, Ke Tang, Ting-yue Gu, En-Ze Zhou, Bo Zhang, Xiu-Liang Ma, Corrosion Communications) investigated the antibacterial and corrosion-resistant properties of Cu and Ce composite materials. This paper revealed that Cu and Ce can improve antibacterial properties and significantly inhibit the corrosion behavior of the material. However, the focus of this study was on the antibacterial ability and corrosion resistance of materials with added Cu and Ce, without delving into the microstructural characteristics of the Cu precipitates. Specifically, the Cu precipitates were not explicitly defined as having a specific crystal structure, such as the 9R-Cu structure; furthermore, it did not address how refining or altering the precipitate structure could enhance antibacterial properties and the slow-release characteristics of copper ions. While the literature mentions the Cu ion release rate and its initial antibacterial effect, it primarily focuses on optimizing the material's surface properties. It does not delve into the crystal structure, stability, and slow-release characteristics of the Cu precipitates, nor does it analyze the specific impact of different precipitates (such as 9R-Cu) on antibacterial performance from a crystallographic perspective. Therefore, existing literature on the regulation of Ce focuses more on improving the material surface and enhancing corrosion resistance, rather than on controlling the antibacterial effect of Cu from the perspective of the microstructure of the precipitates.

[0006] Copper precipitates in alloys typically follow a specific evolutionary sequence: body-centered cubic (BCC) Cu, 9R-Cu, 3R-Cu, and the stable face-centered cubic (FCC) Cu. Among these, 9R-Cu, representing a metastable stage in the evolution of copper precipitates, generally exhibits high interfacial energy and strong chemical reactivity. Compared to the later FCC-Cu structure, the 9R-Cu precipitate is smaller, has a higher number density, abundant interfaces, and stronger compatibility with the matrix. Therefore, it possesses a larger specific surface area and more active sites, which helps maintain the continuous release of copper ions.

[0007] Existing research indicates that the size, number density, and total surface area of ​​the precipitated phase are crucial factors affecting the antibacterial properties of materials. Fine, uniformly distributed precipitates not only increase the effective interfacial area of ​​the material but also enhance the duration of antibacterial activity by regulating the release rate of copper ions. Therefore, the metastable structure of the 9R-Cu precipitate exhibits better antibacterial durability and sustained copper ion release capability, a point supported by existing literature but not yet fully utilized in practical material design.

[0008] In summary, existing nano-copper antibacterial steel technologies typically face two major problems: First, the antibacterial performance decays rapidly: the antibacterial effect of traditional copper alloy antibacterial materials mainly relies on the rapid release of copper ions in the initial stage, but as time goes on, the copper precipitates coarsen and the ion release rate decreases, leading to a gradual decline in antibacterial performance; second, the control of copper precipitates is insufficient: existing research mainly relies on the total copper content or surface enrichment layer to improve antibacterial performance, with less emphasis on the regulation of precipitates, especially lacking in-depth analysis of the impact of different copper precipitates (such as 9R-Cu) on antibacterial performance.

[0009] By controlling the copper precipitate phase, nano-copper antibacterial steel is designed and optimized to achieve a controllable and continuous antibacterial effect, which has broad application prospects. Summary of the Invention

[0010] This invention provides a nano-copper antibacterial steel based on rare earth elements and its preparation method, characterized by controlled release of copper precipitates. By introducing appropriate amounts of rare earth elements into the nano-copper antibacterial steel and employing a reasonable heat treatment process, the morphology and distribution of the copper precipitates are precisely controlled. In particular, by controlling the formation of the 9R-Cu precipitate and stabilizing it in a metastable 9R-Cu structure, the Cu content is significantly improved. 2+ The invention utilizes a slow-release capability, thereby significantly extending the duration of its antibacterial properties; it also improves the resistance to hydrogen embrittlement in nano-copper antibacterial steel materials, making them suitable for highly corrosive, humid, or hydrogen-containing environments. This invention is specifically achieved through the following techniques.

[0011] The core technology of this invention lies in the fact that the structural transformation and stabilization of the Cu precipitate phase are achieved through the regulatory effect of rare earth elements such as Ce, thereby improving the antibacterial function and sustained-release performance, and solving the problems of antibacterial effect decay and Cu precipitate phase coarsening in existing copper-based antibacterial materials.

[0012] (1) Design of the chemical composition of steel

[0013] By introducing appropriate amounts of rare earth elements such as Ce, the morphology and distribution of copper precipitates in steel are controlled. The addition of rare earth elements regulates the crystal structure of the precipitates, particularly the 9R-Cu precipitate, achieving controlled and sustained release of Cu with enhanced stability. This process effectively overcomes the problems encountered in traditional copper-containing antibacterial materials where the precipitates coarsen or transform into FCC-Cu, leading to Cu degradation.2+ Release the bottleneck of decay.

[0014] Regulation of Cu precipitates: The addition of rare earth elements raises the migration barrier of Cu in the steel matrix, inhibits long-range diffusion and coarsening of Cu, promotes the preferential formation of the 9R crystal structure of Cu precipitates, and delays the formation of FCC-Cu. Compared with FCC-Cu, the 9R-Cu crystal structure has higher stability and can continuously release Cu during long-term use. 2+ Ions, thereby prolonging the antibacterial effect.

[0015] Slow-release antibacterial mechanism: The addition of rare earth elements stabilizes the morphology of the 9R-Cu precipitate, thereby improving the Cu content. 2+ By controlling the release rate, a controllable and sustained antibacterial effect is achieved.

[0016] Improved resistance to hydrogen embrittlement: The introduction of rare earth elements also significantly improves the hydrogen embrittlement resistance of the material, which is of great significance for the application of antibacterial steel in practical environments.

[0017] Based on this, the present invention provides a nano-copper antibacterial steel based on rare earth elements for regulating the slow release of copper precipitates. The chemical composition of the nano-copper antibacterial steel, by mass percentage, includes C 0.06-0.12%, Mn 0.6-1.2%, Si 0.15-0.60%, Cu 0.6-2.0%, rare earth elements 0.005-0.030%, and the remainder being Fe and unavoidable impurity elements.

[0018] The rare earth elements, by regulating the morphology and size of the copper precipitate, inhibit the transformation of the copper precipitate to the FCC-Cu structure, and improve the stability of the copper precipitate in the nano-copper antibacterial steel and the slow release of Cu. 2+ The ability of ions.

[0019] The copper precipitate in the slow-release antibacterial steel provided by this invention has the following structural characteristics: it mainly exhibits a 9R-Cu crystal structure, which is a metastable state of Cu precipitates; the particle size of the copper precipitate is in the nanometer range (approximately 5 nm), and it has a high number density; the copper precipitate is not easily transformed into FCC-Cu during the long-term use of the steel, maintaining its 9R structure, thereby avoiding Cu... 2+ Release decay.

[0020] Stability and sustained-release effect of precipitated phases: Rare earth elements such as Ce effectively inhibit the rapid aggregation and precipitation of Cu by regulating the morphology and distribution of the precipitated phases, ensuring that the Cu precipitates always exist in the form of fine, high-density 9R-Cu. This structural feature effectively improves the stability and sustained-release effect of Cu. 2+ It ensures sustained release and guarantees that the antibacterial effect remains significant even after prolonged use.

[0021] Precipitated phase stability: The increase in the Cu migration energy barrier significantly reduces the migration rate of Cu atoms, thereby suppressing the coarsening of the precipitated phase.

[0022] Slow-release function: This material can stably release Cu during long-term use. 2+ And the release rate will not decrease sharply due to the coarsening of the precipitated phase.

[0023] Furthermore, the Cu content in the chemical composition of the nano-copper antibacterial steel is 0.8-1.2% by mass percentage.

[0024] Furthermore, the rare earth element content in the chemical composition of the nano-copper antibacterial steel is 0.010-0.020% by mass percentage.

[0025] Furthermore, the chemical composition of the nano-copper antibacterial steel also includes at least one of Cr, Nb, and Ni; by mass percentage, the content of Cr does not exceed 1.0%, the content of Nb does not exceed 0.05%, and the content of Ni does not exceed 1.0%.

[0026] Furthermore, the rare earth element is Ce.

[0027] Furthermore, the copper precipitates in the nano-copper antibacterial steel are mainly composed of a 9R-Cu structure, with a particle size of 2-20 nm and a number density of 1×10⁻⁶. 14 pcs / m 2 - 1×10 16 pcs / m 2 .

[0028] This invention also provides a method for preparing the above-mentioned rare earth element-based controlled release of copper precipitate nano-copper antibacterial steel, comprising the following steps:

[0029] The steel molten material is obtained by smelting according to the composition of each chemical component, ensuring that Ce can be fully dissolved and evenly distributed in the steel molten material, laying the foundation for subsequent control effects.

[0030] The castings are poured sequentially and homogenized to eliminate compositional segregation.

[0031] The billet is hot-rolled, cooled, and aged to obtain the nano-copper antibacterial steel.

[0032] The rare earth elements control the diffusion rate of the copper precipitate, inhibit the long-range diffusion of copper, prolong the release time of copper ions, and maintain the durability of the antibacterial effect.

[0033] Furthermore, the hot rolling temperature is 800-1050℃.

[0034] Optionally, a two-stage control strategy is adopted for hot rolling. The first stage is rough rolling in a high-temperature range of 950-1050℃, and the second stage is finish rolling in a medium-temperature range of 800-880℃; this can obtain fine and uniform austenite grains, providing a favorable microstructure basis for subsequent phase transformation and precipitation.

[0035] Optionally, during controlled cooling, the cooling rate is controlled at 3-8 ℃ / s, and the cooling termination temperature is set at 480-520℃. This temperature range falls precisely within the sensitive range for Cu precipitation, creating favorable conditions for subsequent low-temperature precipitation treatment.

[0036] Furthermore, the aging treatment method is as follows: heat treatment at 450-520℃ for 0.2-3 hours.

[0037] Tempering / aging treatment is the core step in the entire preparation process of nano-copper antibacterial steel in this invention. The precipitation temperature is precisely controlled within the range of 420-480℃, which is the optimal precipitation temperature window determined based on the regulation mechanism of rare earth elements such as Ce. At this temperature, the 9R-Cu phase can be fully precipitated and achieve the optimal size distribution. The holding time is set to 0.2-3 hours, and the specific time depends on the thickness of the material and the required degree of precipitation.

[0038] Compared with the prior art, the advantages of the present invention are:

[0039] 1. Achieve control over Cu functionality at the level of precipitated phase structure, rather than simply relying on Cu content.

[0040] This invention does not achieve antibacterial function by simply increasing Cu content or adding antibacterial elements. Instead, it introduces an appropriate amount of rare earth elements to regulate the structural morphology and evolution behavior of copper precipitates in nano-copper antibacterial steel from the perspective of precipitate structure, so that the copper precipitates preferentially form and remain stably in the 9R structure.

[0041] Compared with the coarsening problem of FCC-Cu precipitates that is common in existing technologies, this invention significantly improves the stability of Cu functional carriers inside the material through structural regulation, providing a new technical path for the continuous functioning of Cu.

[0042] 2. Constructing a stable Cu functional carrier with high interfacial density is beneficial for the long-term sustainability of Cu action.

[0043] The 9R-Cu precipitate formed in this invention has a nanoscale size and a high number density, and it forms a large number of stable interfaces with the matrix. Compared with coarse precipitates, this type of microstructure has a higher specific surface area and a more uniform distribution, which is beneficial for Cu-related substances to continuously participate in interfacial reactions during the material's service life.

[0044] Therefore, this invention constructs a structural basis at the material microstructure level that is conducive to the long-term stable performance of Cu, overcoming the problem of rapid functional decay caused by coarsening of precipitated phases in existing Cu-containing materials during use.

[0045] 3. By regulating the precipitation kinetics with rare earth elements, the coarsening of Cu precipitates and structural failure can be suppressed.

[0046] The introduction of rare earth elements raises the migration energy barrier of Cu atoms in the matrix, slowing down the growth and aggregation of copper precipitates and suppressing the rapid transformation of the precipitates into a stable FCC structure from a kinetic perspective. This allows the copper precipitates to maintain a fine and dispersed distribution over a longer period, significantly improving the service stability of the precipitate structure and providing a reliable guarantee for long-term functional applications.

[0047] 4. To provide a controllable and designable tissue basis for realizing the sustained-release antibacterial function of Cu.

[0048] By synergistically controlling the rare earth element content and heat treatment regime, this invention achieves controllable adjustment of the structure, size, and distribution of copper precipitates, enabling the formation of a designable and controllable Cu functional carrier system within the material. This system provides stable physical and organizational conditions for Cu to participate in the external environment in a slow-release manner during material use, thus laying a reliable material foundation for achieving functional applications such as long-term antibacterial properties.

[0049] 5. Taking into account the stability of materials during service, the application environment adaptability of antibacterial steel has been expanded.

[0050] In addition to functional stability, this invention improves the diffusion behavior and interface characteristics of the material to a certain extent by regulating the precipitated phase and interface structure through rare earth elements, which is beneficial to improving the material's structural stability in complex environments.

[0051] Therefore, this invention is not only suitable for applications requiring long-term antibacterial function, but also for complex service environments such as dampness and corrosion, thus expanding the application range and reliability of Cu-containing antibacterial steel. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of four different types of copper-rich precipitation structures for hydrogen capture, whether or not they are doped with Ce atoms. Detailed Implementation

[0053] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] This invention aims to provide a slow-release antibacterial steel based on rare earth element-controlled copper precipitate phase regulation. This steel, by introducing appropriate amounts of rare earth elements and combining them with a reasonable heat treatment process, regulates the morphology and distribution of Cu precipitates in Cu-containing steel. In particular, by controlling the formation and stabilization of the 9R-Cu precipitate phase, Cu... 2+ Controllable and sustained release. At the same time, the introduction of rare earth elements solves the problems of antibacterial effect decay and Cu precipitation phase coarsening in existing copper-based antibacterial materials; it not only prolongs the durability of antibacterial effect, but also improves the material's resistance to hydrogen embrittlement, making the material suitable for highly corrosive, humid or hydrogen-containing environments.

[0055] In some embodiments of the present invention, the chemical composition of the nano-copper antibacterial steel, by mass percentage, includes C 0.06-0.12%, Mn 0.6-1.2%, Si 0.15-0.60%, Cu 0.6-2.0%, rare earth elements 0.005-0.030%, and the remainder being Fe and unavoidable impurity elements (such as S, P, etc.).

[0056] Furthermore, the Cu content in the chemical composition of the nano-copper antibacterial steel is 0.8-1.2% by mass percentage.

[0057] Furthermore, the rare earth element content in the chemical composition of the nano-copper antibacterial steel is 0.010-0.020% by mass percentage.

[0058] Furthermore, the chemical composition of the nano-copper antibacterial steel also includes at least one of Cr, Nb, and Ni; by mass percentage, the content of Cr does not exceed 1.0%, the content of Nb does not exceed 0.05%, and the content of Ni does not exceed 1.0%.

[0059] Furthermore, the rare earth element is Ce.

[0060] Furthermore, the copper precipitates in the nano-copper antibacterial steel are mainly composed of a 9R-Cu structure, with a particle size of 2-20 nm and a number density of 1×10⁻⁶. 14 pcs / m 2 - 1×10 16 pcs / m 2 .

[0061] Furthermore, the rare earth elements, by regulating the morphology and size of the Cu precipitate, inhibit the transformation of the Cu precipitate to the FCC-Cu structure, and improve the stability of the Cu precipitate in the material and the slow release of Cu. 2+ The ability of ions.

[0062] The core innovation of this invention lies in the introduction of appropriate amounts of rare earth elements (such as Ce).

[0063] The addition of rare earth elements (such as Ce) raises the migration barrier of Cu in the steel matrix, inhibits long-range diffusion and coarsening of Cu, and precisely controls the morphology and distribution of copper precipitates through rare earth elements. This promotes the preferential formation of fine, high-density 9R crystal structures (i.e., 9R-Cu precipitates), stabilizing them within the metastable 9R-Cu structure and delaying the formation of FCC-Cu. Compared to FCC-Cu, the 9R-Cu crystal structure exhibits higher stability and can continuously release Cu during long-term use. 2+ Ions, thereby prolonging the antibacterial effect.

[0064] The introduction of rare earth elements (such as Ce) also significantly improves the material's resistance to hydrogen embrittlement, which is of great significance for the application of antibacterial steel in practical environments.

[0065] This invention also provides a method for preparing the above-mentioned rare earth element-based controlled release of copper precipitate nano-copper antibacterial steel, comprising the following steps:

[0066] Molten steel is obtained by smelting according to the composition of each chemical component;

[0067] The castings are poured sequentially and homogenized.

[0068] The billet is hot-rolled, cooled, and aged to obtain the nano-copper antibacterial steel.

[0069] The rare earth elements control the diffusion rate of the copper precipitate, inhibit the long-range diffusion of copper, prolong the release time of copper ions, and maintain the durability of the antibacterial effect.

[0070] Furthermore, the hot rolling temperature is 800-1050℃.

[0071] Furthermore, the aging treatment method is as follows: heat treatment at 450-520℃ for 0.2-3 hours.

[0072] Example 1

[0073] The nano-copper antibacterial steel provided in this embodiment has the following chemical composition by mass percentage: C 0.088%, Mn 0.9%, Si 0.29%, Cu 0.93%, Ce 0.013%, Ni 0.52%, Nb 0.017%, Cr 0.5%, Ti 0.021%, with the remainder being Fe and unavoidable impurity elements.

[0074] The specific preparation method of nano-copper antibacterial steel is as follows:

[0075] Step A: Smelting and Composition Control

[0076] In induction furnaces or electric arc furnaces, molten steel is smelted using rare earth master alloys, which are added to the molten steel at a high temperature of 1580-1680℃. This temperature range ensures that Ce can fully dissolve and be uniformly distributed in the molten steel, laying the foundation for subsequent control effects.

[0077] Step B: Homogenization

[0078] The continuously cast billet is heated to 1150-1200°C and held for 60-180 min (specifically, 80-120 min) to homogenize it and eliminate component segregation.

[0079] Step C: Controlling the rolling process

[0080] A two-stage control strategy is adopted. The first stage is rough rolling in a high-temperature range of 950-1050℃, and the second stage is finish rolling in a medium-temperature range of 800-880℃. This can obtain fine and uniform austenite grains, providing a favorable microstructure for subsequent phase transformation and precipitation.

[0081] Step D: Controlling the cooling process

[0082] The cooling rate was controlled at 3-8℃ / s, and the cooling termination temperature was set at 480-520℃. This temperature range is exactly within the sensitive range for Cu precipitation, creating favorable conditions for subsequent low-temperature precipitation treatment.

[0083] Step E, Tempering / Aging Treatment

[0084] This is the core of the entire process. The precipitation temperature is precisely controlled within the range of 450-480℃, which is the optimal precipitation temperature window determined based on the Ce control mechanism. At this temperature, the 9R-Cu phase can fully precipitate and achieve the optimal size distribution. The holding time is set to 0.2-3 h (e.g., 0.2-1 h), with the specific time determined based on the material thickness (e.g., 8 mm) and the desired degree of precipitation.

[0085] Example 2

[0086] The nano-copper antibacterial steel provided in this embodiment has the following chemical composition by mass percentage: C 0.095%, Mn 0.9%, Si 0.31%, Cr 0.55%, Nb 0.021%, Ni 0.41%, Cu 0.96%, Ce 0.019%, with the remainder being Fe and unavoidable impurity elements. The preparation method of the nano-copper antibacterial steel is the same as in Example 1.

[0087] Comparative Example 1

[0088] The nano-copper antibacterial steel provided in this comparative example has the following chemical composition by mass percentage: C 0.09%, Mn 0.9%, Si 0.3%, Cu 0.99%, Ni 0.22%, Nb 0.02%, Cr 0.54%, Ti 0.019%, with the remainder being Fe and unavoidable impurity elements. That is, compared to Example 1, the nano-copper antibacterial steel provided in this comparative example does not contain Ce.

[0089] Experimental Example: Metallographic Structure Analysis of Nano-Copper Antibacterial Steel

[0090] This experimental example uses the nano-copper antibacterial steel prepared in the above-mentioned examples and comparative examples to observe the microstructure of each nano-copper antibacterial steel. For example... Figure 1 As shown, from Figure 1 As can be seen, the addition of rare earth element Ce significantly increases the number of copper-rich nanophases in the material, achieving the slow release of Cu2+ ions. Furthermore, the proportion of 9R-Cu precipitates in the Cu-rich nanophases is greatly increased, which further enhances the antibacterial effect of the material.

[0091] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A nano-copper antibacterial steel based on rare earth elements for controlled release of copper precipitates, characterized in that, The chemical composition of the nano-copper antibacterial steel, by mass percentage, includes C 0.06-0.12%, Mn 0.6-1.2%, Si 0.15-0.60%, Cu 0.6-2.0%, rare earth elements 0.005-0.030%, and the remainder being Fe and unavoidable impurity elements; The rare earth elements, by regulating the morphology and size of the copper precipitate, inhibit the transformation of the copper precipitate to the FCC-Cu structure, and improve the stability of the copper precipitate in the nano-copper antibacterial steel and the slow release of Cu. 2+ The ability of ions.

2. The nano-copper antibacterial steel based on rare earth element-controlled copper precipitation phase slow release according to claim 1, characterized in that, The Cu content in the chemical composition of the nano-copper antibacterial steel is 0.8-1.2% by mass percentage.

3. The nano-copper antibacterial steel based on rare earth element-controlled copper precipitation phase slow release according to claim 1, characterized in that, The rare earth element content in the chemical composition of the nano-copper antibacterial steel is 0.010-0.020% by mass percentage.

4. The nano-copper antibacterial steel based on rare earth element-controlled copper precipitation phase slow release according to claim 1, characterized in that, It also includes at least one of Cr, Nb, and Ni; by mass percentage, the content of Cr does not exceed 1.0%, the content of Nb does not exceed 0.05%, and the content of Ni does not exceed 1.0%.

5. The nano-copper antibacterial steel based on rare earth element-controlled copper precipitation phase slow release according to claim 1, characterized in that, The rare earth element is Ce.

6. The nano-copper antibacterial steel based on rare earth element-controlled copper precipitation phase slow release according to claim 1, characterized in that, In the copper precipitate of the nano-copper antibacterial steel, the proportion of the 9R-Cu phase is not less than 20%, the particle size of the precipitate is 2-20 nm, and the number density is 1×10⁻⁶. 14 pcs / m 2 - 1×10 16 pcs / m 2 .

7. A method for preparing nano-copper antibacterial steel based on rare earth element-controlled copper precipitate slow release as described in any one of claims 1-6, characterized in that, Includes the following steps: Molten steel is obtained by smelting according to the composition of each chemical component; The castings are poured sequentially and homogenized. The billet is hot-rolled, cooled, and aged to obtain the nano-copper antibacterial steel. The rare earth elements control the diffusion rate of the copper precipitate, inhibit the long-range diffusion of copper, prolong the release time of copper ions, and maintain the durability of the antibacterial effect.

8. The method for preparing nano-copper antibacterial steel based on rare earth element-controlled copper precipitation phase slow release according to claim 7, characterized in that, The hot rolling temperature is 800-1050℃.

9. The method for preparing nano-copper antibacterial steel based on rare earth element-controlled copper precipitation phase slow release according to claim 7, characterized in that, The aging treatment method is as follows: heat treatment at 450-520℃ for 0.2-3 hours.

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