Steel material, method for producing the same, electronic device structural member, and electronic device

Abstract

The application provides a steel material, a preparation method thereof, an electronic device structural member and an electronic device. The steel material comprises a steel material base body and a reinforcing layer arranged on the surface of the steel material base body in sequence. The reinforcing layer comprises a metal primer layer, a phosphorus alloy layer, a chromium layer, a chromium-tungsten carbide composite layer and a tungsten carbide layer arranged on the surface of the steel material base body in sequence. The metal primer layer comprises at least one of a nickel element and a cobalt element, and the phosphorus alloy layer comprises at least one of a nickel element and a cobalt element. The bonding force between the reinforcing layer and the steel material base body is high, the bonding reliability is strong, the wear resistance and corrosion resistance of the steel material are good, and the use of the steel material is facilitated.

Description

Technical Field

[0001] The present application belongs to the field of electronic product technology, and specifically relates to steel materials and preparation methods thereof, electronic equipment structural parts, and electronic equipment. Background Art

[0002] Steel, with its high mechanical properties, low price, and adaptability to a wide range of processing techniques, has become one of the most widely used materials in the world. However, steel is susceptible to wear and has poor corrosion resistance during use, hindering its long-term use and limiting its applications. Therefore, further research is needed to improve steel's wear and corrosion resistance. Summary of the Invention

[0003] In view of this, the present application provides steel and a preparation method thereof, an electronic equipment structural component and an electronic equipment.

[0004] In a first aspect, the present application provides a steel material comprising a steel substrate and a reinforcing layer sequentially arranged on the surface of the steel substrate, wherein the reinforcing layer comprises a metal base layer, a phosphorus alloy layer, a chromium layer, a chromium-tungsten carbide composite layer and a tungsten carbide layer sequentially arranged on the surface of the steel substrate, the metal base layer comprising at least one of nickel and cobalt elements, and the phosphorus alloy layer comprising at least one of nickel and cobalt elements.

[0005] In second aspect, the present application provides a method for preparing steel, comprising: sequentially forming a metal base layer, a phosphorus alloy layer, a chromium layer, a chromium-tungsten carbide composite layer and a tungsten carbide layer on the surface of a steel substrate to produce steel, wherein the metal base layer includes at least one of nickel and cobalt elements, and the phosphorus alloy layer includes at least one of nickel and cobalt elements.

[0006] In a third aspect, the present application provides an electronic device structural component, wherein the material of the electronic device structural component includes the steel described in the first aspect or the steel produced by the preparation method described in the second aspect.

[0007] In a fourth aspect, the present application provides an electronic device comprising the electronic device structural component described in the third aspect.

[0008] The steel provided in this application has better bonding performance between the steel matrix and the reinforcement layer, and the reinforcement layer has good wear resistance and corrosion resistance, which can improve the wear resistance and corrosion resistance of the steel, and is beneficial to the use of the steel; the preparation method of the steel is easy to operate, which is beneficial to the production and use of the steel; the electronic equipment structural parts formed by the steel have good wear resistance and corrosion resistance, which is beneficial to its use in electronic equipment and improves the performance of the electronic equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments of the present application will be described below.

[0010] Figure 1 A schematic cross-sectional view of a steel material provided in accordance with one embodiment of the present application.

[0011] Figure 2 A schematic cross-sectional view of a steel material provided in another embodiment of the present application.

[0012] Figure 3 A schematic cross-sectional view of a steel material provided in yet another embodiment of the present application.

[0013] Figure 4 A schematic cross-sectional view of a steel material provided in yet another embodiment of the present application.

[0014] Figure 5 A flow chart of a method for preparing steel provided in one embodiment of the present application.

[0015] Figure 6 A flow chart of a method for preparing steel provided in another embodiment of the present application.

[0016] Figure 7 Schematic diagram of the surface of the steel produced in Experiment 1.

[0017] Figure 8 A schematic structural diagram of an electronic device provided in one embodiment of the present application.

[0018] Description of labels:

[0019] Steel 100, steel substrate 10, first surface 11, second surface 12, reinforcing layer 20, metal base layer 21, phosphorus alloy layer 22, chromium layer 23, first chromium film 231, second chromium film 232, chromium-tungsten carbide composite layer 24, tungsten carbide layer 25, diamond-like carbon layer 26, electronic device 200, flexible screen 201, first shell 202, second shell 203, protective part 204. DETAILED DESCRIPTION

[0020] The following are exemplary implementations of the present application. It should be noted that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications are also considered to be within the scope of protection of the present application.

[0021] The disclosure below provides many different embodiments or examples for realizing the technical solution of the present application. In order to simplify the disclosure of the present application, the settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art will appreciate the application of other processes and / or the use of other materials.

[0022] Steel is prone to wear and has poor corrosion resistance during use, limiting its use. Related technologies improve steel performance by phosphating it to form a phosphide film on the surface. While this improves corrosion resistance, it does not improve wear resistance. Related technologies also use chemical plating to form a protective layer on the surface of steel, which has limited improvements in corrosion resistance and no improvement in wear resistance. This limits the application of steel and hinders its widespread use.

[0023] In view of this, the present application provides a steel material with excellent corrosion resistance and wear resistance, which is conducive to the use of steel materials in different application scenarios. Figure 1 , is a schematic cross-sectional view of a steel material provided in one embodiment of the present application. The steel material 100 includes a steel substrate 10 and a reinforcement layer 20 arranged on the surface of the steel substrate 10. The reinforcement layer 20 includes a metal base layer 21, a phosphorus alloy layer 22, a chromium layer 23, a chromium-tungsten carbide composite layer 24 and a tungsten carbide layer 25 stacked in sequence on the surface of the steel substrate 10. The metal base layer 21 includes at least one of nickel and cobalt elements, and the phosphorus alloy layer 22 includes at least one of nickel and cobalt elements. Among them, the metal base layer 21 plays a role of base and connection, ensuring a stable and reliable connection between the reinforcement layer 20 and the steel substrate 10, and improving the reliability of the overall structure of the steel 100; the phosphorus alloy layer 22 can protect the steel substrate 10 and improve the corrosion resistance of the steel 100; the chromium layer 23 plays a role in connecting the phosphorus alloy layer 22 and the chromium-tungsten carbide composite layer 24, improving the internal connection performance of the reinforcement layer 20; the chromium-tungsten carbide composite layer 24 plays a role in connecting the chromium layer 23 and the tungsten carbide layer 25, relieving internal stress and avoiding the problem of cracking or falling off of the reinforcement layer 20; tungsten carbide has high hardness and good wear resistance, which improves the wear resistance of the steel 100; therefore, the steel 100 with the reinforcement layer 20 has good wear resistance and corrosion resistance, and at the same time, the reinforcement layer 20 has good bonding with the steel 100, and the internal bonding reliability of the reinforcement layer 20 is high, which ensures the structural stability and reliability of the steel 100, which is beneficial to the use of the steel 100.

[0024] In the present application, a metal primer layer 21 is used as a base in the reinforcement layer 20. The metal primer layer 21 includes at least one of nickel and cobalt. The metal primer layer 21 has a high bonding strength with the steel substrate 10, which improves the bonding performance between the reinforcement layer 20 and the steel substrate 10 and helps to maintain the wear resistance and corrosion resistance of the steel 100 for a long time. In one embodiment of the present application, the thickness of the metal primer layer 21 is 1 μm to 2 μm. The thin and appropriate thickness of the metal primer layer 21 can not only further improve the bonding performance between the reinforcement layer 20 and the steel substrate 10, but also facilitate the provision of the phosphorus alloy layer 22, improve the reliability of the internal bonding of the reinforcement layer 20, and help to further improve the stability of the wear resistance and corrosion resistance of the steel 100. Specifically, the thickness of the metal base layer 21 may be, but is not limited to, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, or 2 μm. In one embodiment of the present application, the thickness of the metal base layer 21 may be 1.3 μm to 1.9 μm, which is beneficial for further enhancing the connection reliability within the layer 20.

[0025] In the present application, the phosphorus alloy layer 22 includes at least one of nickel and cobalt, which makes the phosphorus alloy layer 22 highly dense and can effectively improve the corrosion resistance of the steel 100. At the same time, the metal base layer 21 and the phosphorus alloy layer 22 include at least one of nickel and cobalt. The internal stress between the metal base layer 21 and the phosphorus alloy layer 22 is small and the bonding strength is high, which ensures the internal reliability of the reinforcement layer 20 and the stable connection between the phosphorus alloy layer 22 and the steel substrate 10, thereby ensuring the improvement of the corrosion resistance of the steel 100. In one embodiment of the present application, the thickness of the phosphorus alloy layer 22 is 5μm to 15μm, which can further improve the corrosion resistance of the steel 100 while ensuring the bonding reliability of the overall structure of the steel 100. Specifically, the thickness of the phosphorus alloy layer 22 may be, but is not limited to, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 10 μm, 10.5 μm, 11 μm, 12 μm, 13 μm, 14 μm, or 15 μm. In one embodiment of the present application, the thickness of the phosphorus alloy layer 22 may be 6 μm to 14.5 μm, which is beneficial for further improving the performance of the steel 100.

[0026] In the present application, the metal base layer 21 includes at least one of nickel and cobalt, and the phosphorus alloy layer 22 includes at least one of nickel and cobalt. In one embodiment of the present application, the metal base layer 21 and the phosphorus alloy layer 22 both contain nickel, or cobalt, or both nickel and cobalt. This helps further enhance the bonding strength between the two and improves the structural stability and reliability of the steel 100. In one embodiment of the present application, the metal base layer 21 can include at least one of a nickel layer, a cobalt layer, and a nickel-cobalt mixed layer; the phosphorus alloy layer 22 can include at least one of a nickel-phosphorus alloy layer, a cobalt-phosphorus alloy layer, and a nickel-cobalt-phosphorus alloy layer. In one embodiment of the present application, the metal base layer 21 is a cobalt layer, and the phosphorus alloy layer 22 is a cobalt-phosphorus alloy layer. Both the metal base layer 21 and the phosphorus alloy layer 22 contain cobalt, resulting in good interface bonding between the two. At the same time, the cobalt-phosphorus alloy layer has good density, which helps improve the corrosion resistance and internal connection reliability of the steel 100. In one embodiment of the present application, the cobalt layer can be formed by electroplating, which can further improve the adhesion of the cobalt layer to the surface of the steel 100 and facilitate the formation of a thin and dense cobalt layer, further improving the performance of the steel 100. In one embodiment of the present application, the cobalt-phosphorus alloy layer can be formed by electroplating, which can facilitate the production of a cobalt-phosphorus alloy layer with high density, good thickness uniformity, and a slightly thicker thickness. In another embodiment of the present application, the metal base layer 21 is a nickel layer, and the phosphorus alloy layer 22 is a nickel-phosphorus alloy layer. Both the metal base layer 21 and the phosphorus alloy layer 22 contain nickel, resulting in excellent interfacial bonding between them. The nickel-phosphorus alloy layer also has good density, which helps improve the corrosion resistance and internal connection reliability of the steel 100. In one embodiment of the present application, the nickel layer is a strike nickel layer. That is, the nickel layer can be formed by strike nickel plating, which can further improve the adhesion of the nickel layer to the surface of the steel 100. In one embodiment of the present application, the nickel-phosphorus alloy layer can be formed by electroplating, which can facilitate the production of a nickel-phosphorus alloy layer with high density, good thickness uniformity, and a slightly thicker thickness.

[0027] In the present application, the chromium layer 23 connects the phosphorus alloy layer 22 and the chromium-tungsten carbide composite layer 24, avoiding the problem of poor adhesion caused by a large difference in interface performance between the phosphorus alloy layer 22 and the chromium-tungsten carbide composite layer 24 when directly connected, and improving the stability of the internal structure of the reinforcement layer 20. In one embodiment of the present application, the thickness of the chromium layer 23 is less than or equal to 3 μm, which helps further improve the stability of the internal structure of the reinforcement layer 20 and enhance the reliability of the overall wear resistance of the steel material 100.

[0028] In one embodiment of the present application, the chromium layer 23 includes a first chromium film 231 and a second chromium film 232 disposed between the first chromium film 231 and the chromium-tungsten carbide composite layer 24. In other words, the first chromium film 231 is disposed between the phosphorus alloy layer 22 and the second chromium film 232. The first chromium film 231 protects the phosphorus alloy layer 22 from oxidation, thereby improving the corrosion resistance of the steel 100. The second chromium film 232 enhances the bonding stability between the chromium-tungsten carbide composite layer 24 and the phosphorus alloy layer 22, thereby improving the structural stability of the reinforcement layer 20. (See [1] for details.) Figure 2 , is a schematic cross-sectional view of a steel material provided in another embodiment of the present application. The steel material 100 includes a steel substrate 10 and a reinforcement layer 20 disposed on the surface of the steel substrate 10. The reinforcement layer 20 includes a metal base layer 21, a phosphorus alloy layer 22, a first chromium film 231, a second chromium film 232, a chromium-tungsten carbide composite layer 24, and a tungsten carbide layer 25, which are sequentially stacked on the surface of the steel substrate 10. In one embodiment of the present application, the first chromium film 231 is formed by electroplating, and the second chromium film 232 is formed by deposition. The first chromium film 231 formed by electroplating has a better density than the second chromium film 232 formed by deposition. The first chromium film 231 can further improve the structural stability of the reinforcement layer 20. In one embodiment of the present application, the thickness of the first chromium film 231 is 0.3μm to 1.5μm, which is conducive to further improving the structural stability of the reinforcement layer 20. Specifically, the thickness of the first chromium film 231 may be, but is not limited to, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, or 1.5 μm. In one embodiment, the thickness of the first chromium film 231 may be 0.5 μm to 1.3 μm, further improving the structural stability of the reinforcement layer 20 and the steel material 100. In one embodiment of the present application, the thickness of the second chromium film 232 is 0.1 μm to 1.5 μm, which further improves the structural stability of the reinforcement layer 20. Specifically, the thickness of the second chromium film 232 may be, but is not limited to, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, or 1.5 μm. In one embodiment, the thickness of the second chromium film 232 may be 0.2 μm to 1.35 μm, further improving the structural stability of the reinforcement layer 20 and the steel material 100.

[0029] In the present application, the chromium-tungsten carbide composite layer 24 serves to connect the chromium layer 23 and the tungsten carbide layer 25, avoiding problems such as cracking and falling off of the reinforcement layer 20 caused by large differences in interface properties and high internal stress when the chromium layer 23 and the tungsten carbide layer 25 are directly connected, thereby improving the structural reliability of the steel 100. In one embodiment of the present application, the thickness of the chromium-tungsten carbide composite layer 24 is 0.7μm to 1.7μm, which is conducive to further improving the bonding reliability within the reinforcement layer 20 and between the reinforcement layer 20 and the steel substrate 10. Specifically, the thickness of the chromium-tungsten carbide composite layer 24 can be, but is not limited to, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm or 1.7μm. The material of the chromium-tungsten carbide composite layer 24 includes chromium and tungsten carbide. In one embodiment of the present application, chromium and tungsten carbide are uniformly distributed in the chromium-tungsten carbide composite layer 24. In another embodiment of the present application, along the direction from the second chromium film 232 to the tungsten carbide layer 25, the chromium content in the chromium-tungsten carbide composite layer 24 gradually decreases and the tungsten carbide content gradually increases, thereby further improving the bonding interface performance between the second chromium film 232, the chromium-tungsten carbide composite layer 24, and the tungsten carbide layer 25, and improving the bonding strength and bonding reliability. In one embodiment of the present application, the mass ratio of chromium to tungsten carbide in the chromium-tungsten carbide composite layer 24 can be (0.85-1):1. In one embodiment of the present application, the chromium-tungsten carbide composite layer 24 can be formed by deposition, further improving the internal stress between the second chromium film 232 and the chromium-tungsten carbide composite layer 24, and further improving the structural stability of the reinforcement layer 20.

[0030] In the present application, the tungsten carbide layer 25 has high hardness and good wear resistance, which can improve the surface hardness and wear resistance of the steel 100. At the same time, the tungsten carbide layer 25 has good bonding performance with the chromium-tungsten carbide composite layer 24, ensuring the reliability of the performance of the steel 100. In one embodiment of the present application, the thickness of the tungsten carbide layer 25 is 1.7μm to 2.5μm. Specifically, the thickness of the tungsten carbide layer 25 can be, but is not limited to, 1.7μm, 1.73μm, 1.75μm, 1.8μm, 1.86μm, 1.9μm, 1.95μm, 2μm, 2.1μm, 2.15μm, 2.2μm, 2.25μm, 2.3μm, 2.37μm, 2.4μm, 2.43μm, 2.48μm or 2.5μm, etc. In one embodiment of the present application, the tungsten carbide layer 25 may be formed by deposition, so as to further improve the bonding performance between the chromium-tungsten carbide composite layer 24 and the tungsten carbide layer 25 .

[0031] See also Figure 3, is a schematic cross-sectional view of a steel material according to another embodiment of the present application. The steel material 100 includes a steel substrate 10 and a reinforcement layer 20 disposed on the surface of the steel substrate 10. The reinforcement layer 20 includes a metal primer layer 21, a phosphorus alloy layer 22, a chromium layer 23, a chromium-tungsten carbide composite layer 24, a tungsten carbide layer 25, and a diamond-like carbon layer 26, which are sequentially stacked on the surface of the steel substrate 10. In other words, the reinforcement layer 20 further includes a diamond-like carbon layer 26 disposed on the surface of the tungsten carbide layer 25 facing away from the chromium-tungsten carbide composite layer 24. The diamond-like carbon layer 26 is a metastable, long-range disordered amorphous material. The bonding between carbon atoms is covalent, primarily consisting of sp2 and sp3 hybrid bonds. The diamond-like carbon layer 26 has high hardness, self-lubricity, and excellent wear resistance, further enhancing the hardness and wear resistance of the steel 100. Furthermore, the excellent bonding between the tungsten carbide layer 25 and the diamond-like carbon layer 26 ensures the structural reliability of the steel 100, facilitating its use in more demanding environments and expanding its application range. In one embodiment of the present application, the thickness of the diamond-like carbon layer 26 is 1 μm to 3 μm, further enhancing the internal bonding reliability of the reinforcement layer 20 and the bonding reliability between the reinforcement layer 20 and the steel 100. Specifically, the thickness of the diamond-like carbon layer 26 can be, but is not limited to, 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2 μm, 2.2 μm, 2.5 μm, 2.7 μm, or 3 μm. In one embodiment of the present application, the diamond-like carbon layer 26 may be formed by deposition, thereby further improving the bonding force between the diamond-like carbon layer 26 and the tungsten carbide layer 25 .

[0032] In this application, the reinforcing layer 20 has a strong bond with the steel substrate 10, providing long-term and stable protection for the steel substrate 10. This improves the corrosion and wear resistance of the steel 100, allowing the steel 100 to be used in a variety of environments and expanding its application scenarios. The steel substrate 10 is an iron-carbon alloy with a carbon mass percentage between 0.02% and 2.11%. The reinforcing layer 20 can bond with different types of steel substrates 10, and the strong bond between the two facilitates the use of the steel 100. In one embodiment of this application, the steel substrate 10 comprises at least one of low-carbon steel, medium-carbon steel, and high-carbon steel, depending on the carbon content. In one embodiment of this application, based on the normalized microstructure, the steel substrate 10 comprises at least one of martensitic steel, austenitic steel, bainitic steel, and pearlitic steel. In one embodiment of this application, the steel substrate 10 may comprise ultra-high-strength steel. Ultra-high-strength steel is an alloy steel with a tensile strength exceeding 1470 MPa and a yield strength exceeding 1380 MPa, which further enhances the mechanical properties of the steel 100. Ultra-high-strength steel can include at least one of low-alloy ultra-high-strength steel, medium-alloy ultra-high-strength steel, and high-alloy ultra-high-strength steel. High-alloy ultra-high-strength steel can include at least one of maraging steel and precipitation-hardening stainless steel. In one embodiment of the present application, the steel substrate 10 can include stainless steel. Stainless steel includes at least one of martensitic stainless steel, ferritic stainless steel, austenitic stainless steel, austenitic-ferritic (duplex) stainless steel, and precipitation-hardening stainless steel. In one embodiment of the present application, the steel substrate 10 can include maraging steel. Maraging steel has excellent mechanical properties, but its corrosion and wear resistance are relatively poor, limiting its use. Providing a reinforcement layer 20 on its surface can improve its corrosion and wear resistance, meeting the corrosion and wear resistance requirements during use and facilitating the use of maraging steel.

[0033] In the present application, the steel substrate 10 has a first surface 11 and a second surface 12 arranged opposite to each other. In one embodiment of the present application, Figures 1 to 3 As shown, the reinforcement layer 20 is disposed on the first surface 11 or the second surface 12 of the steel substrate 10. Figure 4, is a schematic cross-sectional view of a steel material according to another embodiment of the present application, in which a reinforcement layer 20 is provided on both the first surface 11 and the second surface 12 of the steel material substrate 10. By providing the reinforcement layer 20 on both the first surface 11 and the second surface 12, the protective effect of the steel material substrate 10 is further enhanced. This eliminates the need to distinguish between the surfaces having the reinforcement layer 20 during use of the steel material 100, further facilitating the use of the steel material 100. The composition and thickness of each layer of the reinforcement layer 20 on the first surface 11 and the second surface 12 can be the same or different. In one embodiment of the present application, a steel material 100 includes a steel substrate 10 and a reinforcement layer 20 disposed on a first surface 11 and a second surface 12 of the steel substrate 10. The reinforcement layer 20 on the first surface 11 includes a metal base layer 21, a phosphorus alloy layer 22, a chromium layer 23, a chromium-tungsten carbide composite layer 24, a tungsten carbide layer 25, and a diamond-like carbon layer 26. The reinforcement layer 20 on the second surface 12 includes a metal base layer 21, a phosphorus alloy layer 22, a chromium layer 23, a chromium-tungsten carbide composite layer 24, and a tungsten carbide layer 25. When the steel material 100 is used as a component, the first surface 11 can face outward and the second surface 12 can face inward, thereby ensuring that the surface of the steel material 100 facing outward is provided with the diamond-like carbon layer 26, further extending the service life of the steel material 100. When the steel material 100 is used as a decorative part, the second surface 12 can face outward and the first surface 11 can face inward, facilitating the installation of other decorative layers on the surface of the tungsten carbide layer 25, thereby enhancing the appearance of the decorative part.

[0034] In one embodiment of the present application, the steel material 100 further comprises a decorative layer. The decorative layer may be disposed on the surface of the reinforcement layer 20 facing away from the steel material substrate 10, and / or on the surface of the steel material substrate 10 facing away from the reinforcement layer 20. The provision of the decorative layer can improve the appearance of the steel material 100 and facilitate its use. Specific decorative layers may include, but are not limited to, color layers, texture layers, optical film layers, and the like.

[0035] In one embodiment of the present application, according to the ASTM D3359 standard, the adhesion between the reinforcing layer 20 and the steel substrate 10 is greater than or equal to 3B, which facilitates the use of the steel 100. In this application, the surface of the reinforcing layer 20 is cross-sectioned using the ASTM D3359 cross-section method to test the adhesion between the reinforcing layer 20 and the steel substrate 10. In one embodiment of the present application, according to the ASTM D3359 standard, the adhesion between the reinforcing layer 20 and the steel substrate 10 is greater than or equal to 4B. In another embodiment of the present application, according to the ASTM D3359 standard, the adhesion between the reinforcing layer 20 and the steel substrate 10 is 5B. This ensures that the reinforcing layer 20 can be stably and long-term adhered to the surface of the steel substrate 10, improving the reliability of the steel 100 and further facilitating the use of the steel 100.

[0036] In one embodiment of the present application, the steel 100 can pass a 16-hour neutral salt spray test. The test conditions of the neutral salt spray test are to use a 4.5% to 5.5% sodium chloride aqueous solution with a pH value of 6.5 to 7.2 to spray through a spray device, so that the salt spray settles on the steel 100, and observe its surface corrosion state after a certain period of time in the test chamber. The test chamber temperature is required to be between 33°C and 37°C, the humidity is greater than 95%, and the fog drop rate is 1mL / (h·cm 2 ) to 2mL / (h·cm 2 ), nozzle pressure is 78.5kPa to 137.3kPa (0.8kgf / cm 2 Up to 1.4kgf / cm 2 ). The steel 100 can pass the 16-hour neutral salt spray test. After 16 hours of surface salt spray test, there is no obvious change on the surface of the steel 100, indicating that the steel 100 has good corrosion resistance. In one embodiment of the present application, the steel 100 can pass the 24-hour neutral salt spray test, and the steel 100 has excellent corrosion resistance. In another embodiment of the present application, the steel 100 can pass the 48-hour neutral salt spray test, which is conducive to the use of the steel 100 in different scenarios or environments, greatly expanding the application range of the steel 100.

[0037] In one embodiment of the present application, after the steel material 100 undergoes a vibration wear resistance test for more than 2 hours, the reinforcement layer 20 on the surface of the steel material substrate 10 does not fall off or become white. Wherein, the vibration wear test comprises mixing 11kg yellow cone abrasive and 4kg green pyramid abrasive at room temperature and adding them to a vibration wear tester, and adding 1L of water at the same time; the abrasive is first air-milled for 8h, and 1L of water is added every half hour; after 8h air-milling, 35mL of lubricant and 500mL of water are started to be put (putting water first and then lubricant), and the steel is assembled into a machine mold (equipped with corresponding heavy iron) and placed in parallel in the vibration wear tester, and the same amount of lubricant and water are added again at 30min and 60min, and thereafter only 500mL of water is added every 30min; after the test, the stop button is pressed, and the steel is taken out for inspection, wherein the frequency set by the vibration wear tester is 1.8Hz-1.9Hz, the voltage is 380V, and the eccentric wheel power is 60%; exemplary, the vibration wear test is carried out using a German ROSLER vibration friction tester, and after a period of test time, the surface reinforcement layer 20 of the steel 100 does not fall off or whiten, indicating that the steel 100 has good wear resistance. In one embodiment of the present application, the reinforcing layer 20 on the surface of the steel substrate 10 of the steel material 100 does not fall off after the vibration wear test of the steel material 100 lasts for more than 3 hours. In another embodiment of the present application, the reinforcing layer 20 on the surface of the steel substrate 10 of the steel material 100 does not fall off after the vibration wear test of the steel material 100 lasts for more than 4 hours. In another embodiment of the present application, the reinforcing layer 20 on the surface of the steel substrate 10 of the steel material 100 does not fall off after the vibration wear test of the steel material 100 lasts for more than 5 hours. In another embodiment of the present application, the reinforcing layer 20 on the surface of the steel substrate 10 of the steel material 100 does not fall off after the vibration wear test of the steel material 100 lasts for more than 6 hours.

[0038] In one embodiment of the present application, the reinforcement layer 20 on the surface of the steel substrate 10 did not fall off or show any whitening after the steel material 100 was subjected to 5000 cycles of weighted friction. The weighted friction process involved applying a 300g weight to the steel material 100 and rubbing the surface of the steel material 100 with the reinforcement layer 20 on a tabletop, with each friction stroke lasting 40cm. After 5000 cycles, the surface condition of the reinforcement layer 20 was observed and classified according to the degree of wear as: no fall-off or whitening, slight whitening at the edge, partial whitening at the edge, whitening at the edge, whitening at the surface, and whitening over a large area. The absence of fall-off or whitening indicated that the reinforcement layer 20 had excellent wear resistance.

[0039] In one embodiment of the present application, the appearance of the steel 100 is normal after the hot and cold shock test, wherein the hot and cold shock test includes placing the steel 100 in a low temperature of -40°C ± 2°C for 1 hour, and then transferring it to a high temperature of 75°C ± 2°C within 1 minute and maintaining it for 1 hour. This is a cycle process. After 40 cycles (a total of 80 hours), it is placed at room temperature to recover for 2 hours. After the hot and cold shock test, the appearance of the steel 100 is observed. If there is no cracking or falling off of the reinforcement layer 20, the appearance is normal. The steel 100 provided in the present application can still maintain a normal appearance after the hot and cold shock test, indicating that the adhesion between the reinforcement layer 20 and the steel substrate 10, as well as between the layers inside the reinforcement layer 20, is strong and stable, and has good impact resistance, which is conducive to the use of the steel 100 in different scenarios.

[0040] The inventors have found that the absence of any one or more of the metal base layer 21, phosphorus alloy layer 22, chromium layer 23, chromium-tungsten carbide composite layer 24 and tungsten carbide layer 25 in the reinforcement layer 20 will affect the wear resistance, corrosion resistance, bonding performance between the reinforcement layer 20 and the steel substrate 10, or internal bonding performance of the reinforcement layer 20 of the steel 100; therefore, the present application provides a reinforcement layer 20 on the surface of the steel substrate 10, so that the wear resistance and corrosion resistance of the steel 100 are excellent, and at the same time, the bonding force between the reinforcement layer 20 and the steel substrate 10 is high and reliable, and the internal connection stability of the reinforcement layer 20 is high, thereby ensuring the long-term stable use of the steel 100.

[0041] This application provides a method for preparing a steel material 100, comprising: sequentially forming a metal base layer 21, a phosphorus alloy layer 22, a chromium layer 23, a chromium-tungsten carbide composite layer 24, and a tungsten carbide layer 25 on the surface of a steel substrate 10 to produce the steel material 100, wherein the metal base layer 21 includes at least one of nickel and cobalt, and the phosphorus alloy layer 22 includes at least one of nickel and cobalt. This method can produce the steel material 100 in any of the aforementioned embodiments.

[0042] See also Figure 5 , is a flow chart of a method for preparing steel provided in one embodiment of the present application, comprising:

[0043] S101: A metal base layer, a phosphorus alloy layer and a first chromium film are sequentially formed on the surface of a steel substrate by an electroplating method.

[0044] S102: forming a second chromium film, a chromium-tungsten carbide composite layer, and a tungsten carbide layer in sequence on the surface of the first chromium film by a deposition method, wherein the chromium layer includes the first chromium film and the second chromium film.

[0045] A dense metal base layer 21 can be formed by the electroplating method, and at the same time, the metal base layer 21 has a good bonding strength with the steel substrate 10, ensuring a reliable connection of the subsequent layer structure; a dense phosphorus alloy layer 22 can be formed by the electroplating method, reducing the penetration of substances in the environment to the steel 100, preventing substances in the environment from penetrating into the steel substrate 10, ensuring the performance of the steel substrate 10, thereby improving the performance of the steel 100, and at the same time, the formed metal base layer 21 and phosphorus alloy layer 22 can eliminate the internal stress generated during the deposition process, avoid the problem of film cracking caused by direct deposition on the steel substrate 10, and improve the structural stability of the reinforcement layer 20. Qualitative analysis: The first chromium film 231 formed by electroplating can protect the phosphorus alloy layer 22 and prevent oxidation. The first chromium film 231 formed by electroplating and the second chromium film 232 formed by deposition have good bonding performance, which can achieve the bonding performance between the layers formed by electroplating and the layers formed by deposition, and improve the bonding force inside the reinforcement layer 20. The bonding force between the second chromium film 232 formed by deposition, the chromium-tungsten carbide composite layer 24 and the tungsten carbide layer 25 is high and stable, thereby improving the internal bonding performance of the reinforcement layer 20 and the bonding performance between the reinforcement layer 20 and the steel substrate 10.

[0046] In the present application, the metal base layer 21 is formed by electroplating. The metal base layer 21 includes at least one of nickel and cobalt. The electroplating process can be selected based on the specific metal element used in the metal base layer 21. In one embodiment of the present application, when the metal base layer 21 includes cobalt, a cobalt layer can be formed on the surface of the steel substrate 10 by electroplating. This cobalt layer can be referred to as a pre-cobalt plating layer. In one embodiment of the present application, the cobalt content in the electroplating solution can be 30 g / L to 60 g / L, which is conducive to the formation of the cobalt layer. In one embodiment, the cobalt content in the electroplating solution can be 35 g / L to 50 g / L. The cobalt salt in the electroplating solution can be, but is not limited to, cobalt chloride. In one embodiment, the cobalt chloride content in the electroplating solution can be 100 g / L to 130 g / L. The electroplating solution also contains an acid, such as hydrochloric acid. For example, the concentration of hydrochloric acid in the electroplating solution can be 70 g / L to 130 g / L. The specific type and concentration of the acid can be selected as needed. In one embodiment of the present application, the electroplating time is 110s to 130s, which is conducive to forming a cobalt layer of appropriate thickness. In one embodiment of the present application, the electroplating voltage is 5V to 7V, which is conducive to forming a dense and uniform cobalt layer. In one embodiment of the present application, the electroplating temperature can be 20°C to 35°C, that is, the preparation process can be carried out in an everyday environment, reducing the difficulty of preparation. After the metal base layer 21 is formed by electroplating, water washing and stain removal can be performed to facilitate the subsequent preparation of the phosphorus alloy layer 22. In one embodiment of the present application, when the metal base layer 21 includes nickel elements, a nickel layer can be formed on the surface of the steel substrate 10 by impact nickel plating. It can be understood that the electroplating solution contains nickel salts in the electroplating to ensure the formation of the nickel layer; the nickel salts can be but are not limited to nickel chloride. In one embodiment of the present application, the nickel content in the electroplating solution is greater than 60g / L, which is conducive to the formation of the nickel layer.

[0047] The present application forms a phosphorus alloy layer 22 by electroplating, and the phosphorus alloy layer 22 includes at least one of nickel and cobalt. The corresponding chemical plating process can be selected according to the specific metal elements in the phosphorus alloy layer 22. In one embodiment of the present application, a cobalt-phosphorus alloy layer is formed on the surface of the metal base layer 21 by electroplating. In one embodiment of the present application, the cobalt content of the electroplating solution in the electroplating is 20g / L to 70g / L (such as 30g / L, 40g / L, 50g / L, 60g / L or 65g / L, etc.), which is conducive to the formation of the cobalt-phosphorus alloy layer. The cobalt salt in the electroplating solution can be, but is not limited to, cobalt sulfate. In one embodiment, the cobalt sulfate content in the electroplating solution can be 140g / L to 180g / L. In one embodiment of the present application, the pH value of the electroplating solution is 2 to 4, which is conducive to the formation of a cobalt-phosphorus alloy layer with less stress. In one embodiment of the present application, the electroplating voltage is 4V to 5V, which is conducive to the formation of a dense and uniform thickness cobalt-phosphorus alloy layer. In one embodiment of the present application, the electroplating temperature is 65°C to 75°C, which is conducive to the formation of a dense and uniformly thick cobalt-phosphorus alloy layer. In one embodiment of the present application, the electroplating time is 560s to 640s, which is conducive to obtaining a cobalt-phosphorus alloy layer of suitable thickness. In one embodiment of the present application, a nickel-phosphorus alloy layer is formed on the surface of the metal base layer 21 by an electroplating method. For details, reference can be made to the process conditions for forming the cobalt-phosphorus alloy layer by electroplating as described above. In one embodiment of the present application, before the phosphorus alloy layer 22 is formed by electroplating, an acid activation treatment is also included, which is conducive to further improving the bonding performance between the phosphorus alloy layer 22 and the metal base layer 21. Specifically, the acid activation treatment can be carried out using a 5mL / L to 15mL / L sulfuric acid solution at room temperature for 20s to 40s. After the phosphorus alloy layer 22 is formed by electroplating, it can be washed with water to facilitate the preparation of subsequent layers.

[0048] The first chromium film 231 is formed by electroplating in the present application. This not only protects the phosphorus alloy layer 22 but also provides good bonding with the phosphorus alloy layer 22. This, in conjunction with the second chromium film 232, enhances the bonding between the electroplated layer and the deposited layer, thereby improving the structural stability of the reinforcement layer 20. In one embodiment of the present application, the chromic anhydride content in the electroplating solution is 250 g / L to 350 g / L, which facilitates the formation of the first chromium film 231. Specifically, the chromic anhydride content in the electroplating solution can be, but is not limited to, 250 g / L to 270 g / L, 270 g / L to 290 g / L, 290 g / L to 300 g / L, 300 g / L to 325 g / L, or 325 g / L to 350 g / L. The electroplating solution also contains an acid, such as sulfuric acid. For example, the sulfuric acid concentration in the electroplating solution can be 1 g / L to 2.4 g / L. In one embodiment of the present application, the electroplating temperature is 35°C to 45°C, which is conducive to the formation of a first chromium film 231 with uniform thickness. In one embodiment of the present application, the electroplating current density is 30A / dm 2Up to 60A / dm 2 (such as 40A / dm 2 、45A / dm 2 、50A / dm 2 or 55A / dm 2 This facilitates the formation of a dense first chromium film 231, further improving the structural stability of the reinforcement layer 20. In one embodiment of the present application, before forming the first chromium film 231 using electroplating, an activation treatment is also included. This facilitates the formation of the first chromium film 231 and improves its bonding with the phosphorus alloy layer 22. In one embodiment of the present application, the activation treatment comprises immersing the first chromium film 231 in an activation solution for 30 to 60 seconds. The activation solution comprises 0.1 to 0.5 mL / L of sulfuric acid and 5 to 10 g / L of chromic anhydride.

[0049] The present application adopts a deposition method to sequentially form a second chromium film 232, a chromium-tungsten carbide composite layer 24 and a tungsten carbide layer 25 on the surface of the first chromium film 231, wherein the deposition method may include but is not limited to at least one of physical vapor deposition and chemical vapor deposition, such as vacuum evaporation, sputtering, ion plating, thermal chemical vapor deposition, plasma chemical vapor deposition, laser chemical vapor deposition, etc. Through these deposition methods, a layer structure with good bonding performance can be formed.

[0050] In one embodiment of the present application, when forming the second chromium film 232 by deposition, the chromium target current may be 20A to 30A, which facilitates uniform formation of the second chromium film 232. Specifically, the chromium target current may be, but is not limited to, 20A to 23A, 22A to 25A, 24A to 27A, or 26A to 30A. In one embodiment of the present application, when forming the second chromium film 232 by deposition, the deposition time may be 15 to 50 minutes. Specifically, the deposition time may be, but is not limited to, 15 to 20 minutes, 20 to 25 minutes, 25 to 30 minutes, 30 to 35 minutes, 35 to 40 minutes, 40 to 45 minutes, or 45 to 50 minutes. In one embodiment of the present application, when forming the second chromium film 232 by deposition, the bias voltage may be 70V to 100V, with a duty cycle of 30% to 50%, which facilitates improved film formation quality of the second chromium film 232. The bias voltage may be a pulsed bias. In one embodiment of the present application, the gas pressure is less than 0.1 Pa when the second chromium film 232 is formed by a deposition method.

[0051] In one embodiment of the present application, when the chromium-tungsten carbide composite layer 24 is formed by a deposition method, the chromium target current can be 20A to 30A, and the tungsten target current can be 15A to 25A, which is conducive to the formation of the chromium-tungsten carbide composite layer 24. Specifically, the chromium target current can be, but is not limited to, 20A to 23A, 22A to 25A, 24A to 27A, or 26A to 30A, and the tungsten target current can be, but is not limited to, 15A to 18A, 17A to 20A, 20A to 23A, or 22A to 25A. The mass ratio of chromium and tungsten carbide in the chromium-tungsten carbide composite layer 24 and the distribution of chromium and tungsten carbide can be adjusted by controlling the chromium target current and the tungsten target current. In one embodiment of the present application, when the chromium-tungsten carbide composite layer 24 is formed by a deposition method, the inert gas flow rate can be 250sccm to 320sccm, and the acetylene gas flow rate can be 50sccm to 90sccm. Specifically, the inert gas flow rate may be, but is not limited to, 260 sccm, 275 sccm, 280 sccm, 300 sccm, or 310 sccm, and the acetylene gas flow rate may be, but is not limited to, 55 sccm, 60 sccm, 65 sccm, 70 sccm, 80 sccm, or 85 sccm. The inert gas may be, but is not limited to, argon. In one embodiment of the present application, the deposition time for forming the chromium-tungsten carbide composite layer 24 by a deposition method is 100 to 200 minutes. Specifically, the deposition time may be, but is not limited to, 100 to 125 minutes, 120 to 150 minutes, 140 to 170 minutes, 150 to 175 minutes, 170 to 190 minutes, or 180 to 200 minutes. In one embodiment of the present application, when forming the chromium-tungsten carbide composite layer 24 by deposition, the bias voltage is 70V to 100V and the duty cycle is 30% to 50%, which is beneficial for improving the film formation quality of the chromium-tungsten carbide composite layer 24. The bias voltage can be a pulsed bias. In one embodiment of the present application, when forming the chromium-tungsten carbide composite layer 24 by deposition, the gas pressure is less than 0.1 Pa.

[0052] In one embodiment of the present application, when the tungsten carbide layer 25 is formed by a deposition method, the tungsten target current can be 15A to 30A, which is conducive to the formation of the tungsten carbide layer 25. Specifically, the tungsten target current can be, but is not limited to, 15A to 18A, 17A to 20A, 20A to 23A, 22A to 25A, or 25A to 30A. In one embodiment of the present application, when the tungsten carbide layer 25 is formed by a deposition method, the inert gas flow rate can be 250sccm to 320sccm, and the acetylene gas flow rate can be 50sccm to 90sccm. Specifically, the inert gas flow rate can be, but is not limited to, 260sccm, 275sccm, 280sccm, 300sccm, or 310sccm, and the acetylene gas flow rate can be, but is not limited to, 55sccm, 60sccm, 65sccm, 70sccm, 80sccm, or 85sccm. The inert gas can be, but is not limited to, argon. In one embodiment of the present application, when the tungsten carbide layer 25 is formed by a deposition method, the deposition time is 100 min to 200 min. Specifically, the deposition time may be, but is not limited to, 100 min to 125 min, 120 min to 150 min, 140 min to 170 min, 150 min to 175 min, 170 min to 190 min, or 180 min to 200 min. In one embodiment of the present application, when the tungsten carbide layer 25 is formed by a deposition method, the bias voltage is 70 V to 120 V, and the duty cycle is 30% to 50%, which is beneficial to improving the film formation quality of the tungsten carbide layer 25. The bias voltage may be a pulse bias voltage. In one embodiment of the present application, when the tungsten carbide layer 25 is formed by a deposition method, the gas pressure is less than 0.1 Pa.

[0053] In one embodiment of the present application, before forming the reinforcement layer 20 on the surface of the steel substrate 10, the steel substrate 10 is pretreated. This pretreatment can remove dirt, oxides, and the like from the surface of the steel substrate 10. In one embodiment of the present application, the pretreatment includes at least one of a physical treatment and a chemical treatment. In one embodiment, the physical treatment can be polishing. Specifically, it can be, but is not limited to, polishing using a magnetic grinding device. In one embodiment, the chemical treatment can include at least one of alkaline degreasing, anodic electrolytic degreasing, and cathodic electrolytic degreasing. Degreasing removes oil stains from the surface of the steel substrate 10. In one embodiment, alkaline degreasing includes treatment in a solution containing 15g / L to 20g / L sodium hydroxide and 45g / L to 55g / L degreasing powder at 50°C to 60°C for 170s to 190s. In one embodiment, the anodic electrolytic degreasing uses a solution containing degreasing powder and sodium hydroxide. The treatment temperature can be 55°C to 65°C, the treatment time can be 50s to 70s, and the voltage can be 5V to 6V. In one embodiment, an electrolytic degreasing powder solution is used for cathodic electrolytic degreasing, the concentration of the electrolytic degreasing powder is 10g / L to 30g / L, the treatment temperature can be 55°C to 65°C, the treatment time can be 50s to 70s, and the voltage is 5V to 6V.

[0054] In one embodiment of the present application, a cleaning treatment may be performed before depositing the second chromium film 232. In one embodiment of the present application, the cleaning treatment includes liquid cleaning and plasma cleaning to remove dirt attached to the surface of the product after electroplating. In one embodiment, liquid cleaning can be performed using a neutral detergent to remove dirt and oil. In one embodiment, during plasma cleaning, the chromium target current is 20A to 30A, the arc target current is 60A to 80A, the bias voltage is 70V to 100V, the duty cycle is 30% to 40%, and the treatment time is 5min to 20min. In one embodiment, the gas pressure during plasma cleaning is less than 0.1Pa. Plasma cleaning can increase the surface energy of the first chromium film 231, which is beneficial to the formation and adhesion of the second chromium film 232.

[0055] In one embodiment of the present application, the method for preparing the steel 100 further includes forming a diamond-like carbon layer 26 on the surface of the tungsten carbide layer 25 facing away from the chromium-tungsten carbide composite layer 24. Providing the diamond-like carbon layer 26 further improves the surface hardness and wear resistance of the steel 100, thereby broadening the application scenarios of the steel 100.

[0056] See also Figure 6 , is a flow chart of a method for preparing steel provided in another embodiment of the present application, comprising:

[0057] S201: forming a metal base layer, a phosphorus alloy layer and a first chromium film in sequence on the surface of the steel substrate by electroplating.

[0058] S202: forming a second chromium film, a chromium-tungsten carbide composite layer, a tungsten carbide layer and a diamond-like carbon layer in sequence on the surface of the first chromium film by a deposition method, wherein the chromium layer includes the first chromium film and the second chromium film.

[0059] The deposition method can improve the quality of the formed diamond-like carbon layer 26 and enhance the bonding strength between the diamond-like carbon layer 26 and the tungsten carbide layer 25, thereby improving the reliability of the steel material 100. In one embodiment of the present application, when forming the diamond-like carbon layer 26 by the deposition method, the inert gas flow rate can be 100 sccm to 150 sccm, and the acetylene gas flow rate can be 250 sccm to 350 sccm. Specifically, the inert gas flow rate can be, but is not limited to, 100 sccm to 120 sccm, 120 sccm to 140 sccm, or 130 sccm to 150 sccm, and the acetylene gas flow rate can be, but is not limited to, 250 sccm to 280 sccm, 270 sccm to 300 sccm, 300 sccm to 330 sccm, or 320 sccm to 350 sccm. The inert gas can be, but is not limited to, argon.

[0060] The present application also provides an electronic device structural component, the material of which includes the steel 100 of any of the above-mentioned embodiments. The electronic device structural component made of the above-mentioned steel 100 has excellent wear resistance and corrosion resistance, and at the same time has good surface hardness, which is conducive to obtaining wear-resistant and corrosion-resistant electronic device structural components and facilitating the use of electronic device structural components. In the present application, the steel 100 can be processed into an electronic device structural component of the desired shape, or a steel substrate 10 of the desired shape can be provided and a reinforcement layer 20 is provided on its surface to directly obtain the electronic device structural component.

[0061] The present application also provides an electronic device 200, including the above-mentioned electronic device structural parts. The electronic device structural parts have excellent wear resistance and corrosion resistance, which ensures the use of the electronic device 200, improves the performance and service life of the electronic device 200, and enhances the competitiveness of the product. It can be understood that the electronic device 200 can be, but is not limited to, mobile phones, tablet computers, laptop computers, watches, MP3, MP4, GPS navigators, digital cameras, drones, vehicles, etc.; electronic device structural parts can be the appearance parts of the electronic device 200, or they can be internal parts of the electronic device 200, etc. Specifically, the electronic device structural parts can be, but are not limited to, the housing, middle frame, buttons, rotating shafts, hinges, gears, supports, protective parts, connectors, supports, etc. of the electronic device 200. Please refer to Figure 8, is a structural schematic diagram of an electronic device provided in one embodiment of the present application, the electronic device 200 includes a flexible screen 201 and a foldable mechanism, the foldable mechanism is used to support the flexible screen 201, the foldable mechanism includes a hinge assembly, a first shell 202 and a second shell 203, the first shell 202, the second shell 203 and the flexible screen 201 are connected and surrounded to form an accommodating interval, and the hinge assembly is arranged in the accommodating interval. In one embodiment, the hinge assembly is an electronic device structural component in any of the above-mentioned embodiments, thereby improving the number of bending times of the hinge assembly and the reliability and service life of the electronic device 200. In another embodiment, at least one of the first shell 202 and the second shell 203 includes the electronic device structural component in any of the above-mentioned embodiments, thereby improving the reliability and service life of the electronic device 200. In another embodiment, the electronic device 200 includes a protective member 204 disposed between a first shell 202 and a second shell 203. The flexible screen 201 has a display surface and a non-display surface disposed opposite each other. The protective member 204 is disposed protruding from the display surface of the flexible screen 201 in a direction perpendicular to the display surface. The protective member 204 is a structural member of the electronic device in any of the above-mentioned embodiments. In this way, when the first shell 202 and the second shell 203 are folded or unfolded under the drive of the hinge assembly, the protective member 204 always protrudes from the display surface, thereby protecting the flexible screen 201. Specifically, the protective member 204 can be connected to the first shell 202 and the second shell 203, and / or the protective member 204 can be connected to the hinge assembly. Specifically, the cross-sectional shape of the protective member 204 can be T-shaped or T-shaped.

[0062] The effects of this application are further illustrated below through specific examples.

[0063] Example 1

[0064] Experiment 1

[0065] Ultra-high-strength steel C300 was used as the steel matrix, and its surface was polished using magnetic grinding equipment to remove surface oxide scale. After treatment, it was cleaned with pure water; then it was placed in an alkaline degreasing solution (including 50g / L alkaline degreasing powder and 18g / L sodium hydroxide) and treated at 55°C for 180s; then it was placed in a solution containing degreasing powder and sodium hydroxide and degreased at 60°C and 5.5V for 60s by anodic electrolysis; finally, it was placed in an electrolytic degreasing powder with a concentration of 20g / L and degreased at 60°C and 5V for 50s by cathodic electrolysis.

[0066] The steel substrate was placed in an electroplating solution (containing 100 g / L cobalt chloride and 100 g / L hydrochloric acid) for 120 seconds to form a cobalt layer (Co) on the surface of the steel substrate. The steel substrate with the cobalt layer was placed in a 10 mL / L sulfuric acid solution for activation at room temperature for 30 seconds, and then placed in an electroplating solution (containing 150 g / L cobalt sulfate, pH 3.4) at a voltage of 4.5 V and a temperature of 70°C for 600 seconds to form a cobalt-phosphorus alloy layer (Co-P) on the surface of the cobalt layer. The steel substrate with the cobalt layer and the cobalt-phosphorus alloy layer was placed in an activation solution (containing 0.3 mL / L sulfuric acid and 7 g / L chromic anhydride) for 45 seconds, and then placed in an electroplating solution (containing 300 g / L chromic anhydride and 2 g / L sulfuric acid) at 40 A / dm 2 , and form a first chromium film (Cr-1) by electroplating under 40°C conditions.

[0067] The steel substrate after forming the first chromium film is placed in a deposition chamber, and is plasma cleaned and then deposited to form a second chromium film (Cr-2), a chromium-tungsten carbide composite layer (Cr-WC) and a tungsten carbide layer (WC) to obtain a steel material, wherein the process conditions for plasma cleaning are as follows: an argon partial pressure of less than 0.001Pa, a chromium target current of 25A, an arc current of 80A, a pulse bias of 90V, a duty cycle of 50%, and arc target co-sputtering for 10min; the process conditions for depositing the second chromium film are as follows: an argon partial pressure of less than 0.001Pa, a chromium target current of 25A, a pulse bias of 80V, a duty cycle of 40%, deposition for 40 min; the process conditions for depositing a chromium-tungsten carbide composite layer are as follows: argon partial pressure less than 0.001 Pa, argon flow rate 300 sccm, C2H2 flow rate 60 sccm, chromium target current 25 A, tungsten target current 20 A, pulse bias 80 V, duty cycle 40%, deposition for 180 min; the process conditions for depositing a tungsten carbide layer are as follows: argon partial pressure less than 0.001 Pa, argon flow rate 300 sccm, C2H2 flow rate 60 sccm, tungsten target current 25 A, pulse bias 100 V, duty cycle 40%, deposition for 180 min.

[0068] See also Figure 7 , which is a schematic diagram of the surface of the steel obtained in Experiment 1. The color Lab value of the surface color of the steel obtained in Experiment 1 was tested by using a colorimeter. L is 30.13, a is 1.08, b is 11.24, and the overall appearance is black.

[0069] Experiment 2-16

[0070] The process is similar to Experiment 1, except that the process conditions are changed to make the thickness of each layer in the reinforcement layer different.

[0071] Experiment 17

[0072] The ultra-high strength steel C300 material after cleaning in Experiment 1 was directly used as the steel material.

[0073] The thickness of each layer in the steel materials obtained in Experiments 1-17 was tested by metallographic microscope or scanning electron microscope, and the results are shown in Table 1.

[0074] Table 1 Thickness of each layer in the reinforcement layer obtained in Experiments 1-17 in Example 1

[0075]

[0076]

[0077] The steels prepared in Experiments 1-17 were subjected to neutral salt spray test, adhesion test, vibration wear test, load wear test, and thermal shock test. The test results are shown in Table 2. The neutral salt spray test was conducted by spraying a 4.5% to 5.5% sodium chloride aqueous solution with a pH value of 6.5 to 7.2 through a spray device to allow the salt spray to settle on the steel. The surface corrosion state was observed in the test chamber for a certain period of time. The test chamber temperature was required to be between 33°C and 37°C, the humidity was greater than 95%, and the mist drop rate was 1 mL / (h·cm 2 ) to 2mL / (h·cm 2 ), nozzle pressure is 78.5kPa to 137.3kPa (0.8kgf / cm 2 Up to 1.4kgf / cm 2 ), if there is no obvious change on the surface of the steel after 4h, 8h, 16h, 24h or 48h of neutral salt spray test, it is passed, otherwise it is recorded as failed. The longer the test time, the better the corrosion resistance of the steel; the adhesion test is carried out by the 100-grid method of ASTM D3359 on the surface of the reinforcement layer to detect the adhesion between the reinforcement layer and the steel substrate; the vibration wear test adopts the German ROSLER vibration friction tester. After a period of test time, the reinforcement layer on the surface of the steel still does not fall off or turn white. The maximum time of the test is recorded as the result of the vibration wear test, wherein the longer the time, the better the wear resistance of the steel; the load-bearing wear test includes applying a 300g counterweight on the steel, rubbing the surface of the steel with the reinforcement layer on the table, and the friction stroke is 40cm once; after After 5000 times, the surface condition of the reinforcement layer is observed and divided into no peeling or whitening, slight whitening at the edge, whitening at the edge, whitening at the edge, whitening at the surface, and whitening at a large area according to the degree of wear; the hot and cold shock test includes placing the steel at a low temperature of -40℃±2℃ for 1 hour, and then transferring it to a high temperature of 75℃±2℃ within 1 minute and maintaining it for 1 hour. This is a cycle process. After 40 cycles (a total of 80 hours), it is placed at room temperature for recovery for 2 hours. After the hot and cold shock test, the appearance of the steel is observed. If there is no cracking or peeling of the reinforcement layer, the appearance is normal.

[0078] Table 2 Test results of steel in Example 1

[0079]

[0080]

[0081] It can be seen from Tables 1 and 2 that, compared with Experiment 17 without any treatment, the addition of a reinforcement layer on the surface of the steel substrate in Experiments 1-16 significantly improved the neutral salt spray time of the steel, thereby improving the corrosion resistance of the steel; at the same time, in the vibration wear test, Experiments 1-16 can maintain the surface integrity of the steel for a test time of more than 2 hours, indicating that the steel has good wear resistance, while Experiment 17 does not have a reinforcement layer. After the same vibration wear test, obvious scratches and even obvious pits appeared on its surface, affecting its use. It can be seen that the setting of the reinforcement layer enhances the wear resistance of the steel; at the same time, according to the adhesion test results, it can be seen that the adhesion between the reinforcement layer and the steel substrate is good, ensuring the reliability of the steel.

[0082] Compared to Experiments 5-14, the thickness of each layer within the reinforcement layer in Experiments 1-4 was more appropriate, the connection reliability was better, and after the load-bearing wear test, there was no problem of falling off or whitening. The overall structural reliability was good, and the appearance was still intact after the thermal shock test. The overall reliability and service life of the steel were improved, which is conducive to the use of steel in more demanding or variable environmental conditions, further expanding the application range of steel. Compared to Experiments 15-16, Experiments 1-4 had both a first chromium layer and a second chromium layer, making the reinforcement layer structure more stable, the bonding between the reinforcement layer and the steel substrate stronger, the overall performance was better, and it was more conducive to the use of steel.

[0083] Example 2

[0084] Experiment 1

[0085] Same as Experiment 1 in Example 1.

[0086] Experiment 2

[0087] It is similar to Experiment 1, except that C350 steel is used as the steel matrix and the thickness of each layer in the reinforcement layer is different.

[0088] Experiment 3

[0089] It is similar to Experiment 1, except that C250 steel is used as the steel matrix and the thickness of each layer in the reinforcement layer is different.

[0090] Experiment 4

[0091] It is similar to Experiment 1, except that 17-4PH steel is used as the steel matrix and the thickness of each layer in the reinforcement layer is different.

[0092] Experiment 5

[0093] It is similar to Experiment 1, except that 420 steel is used as the steel matrix and the thickness of each layer in the reinforcement layer is different.

[0094] Experiment 6

[0095] It is similar to Experiment 1, except that 304 steel is used as the steel matrix and the thickness of each layer in the reinforcement layer is different.

[0096] Experiment 7

[0097] The C300 steel in Experiment 1 was directly used as the steel material.

[0098] Experiment 8

[0099] The C350 steel in Experiment 2 was directly used as the steel material.

[0100] Experiment 9

[0101] The C250 steel in Experiment 3 was directly used as the steel material.

[0102] Experiment 10

[0103] The 17-4PH steel in Experiment 4 was directly used as the steel material.

[0104] Experiment 11

[0105] The 420 steel in Experiment 5 was directly used as the steel material.

[0106] Experiment 12

[0107] The 304 steel in Experiment 6 was directly used as the steel material.

[0108] The thickness of each layer in the steel materials produced in Experiments 1-12 was tested using the method in Example 1, and the results are shown in Table 3. The steel materials produced in Experiments 1-12 were subjected to neutral salt spray testing, adhesion testing, vibration wear resistance testing, load wear resistance testing, and thermal shock testing using the test methods in Example 1, and the test results are shown in Table 4.

[0109] Table 3 Thickness of each layer in the reinforcement layer obtained in Experiments 1-12 in Example 2

[0110] Co / μm Co-P / μm Cr-1 / μm Cr-2 / μm Cr-WC / μm WC / μm Experiment 1 1.81 13.46 0.55 1.35 1.36 2.32 Experiment 2 1.31 9.28 0.87 1.22 1.42 2.12 Experiment 3 1.52 12.11 0.38 1.43 1.51 1.87 Experiment 4 1.68 14.21 1.21 1.56 1.62 2.11 Experiment 5 1.73 13.2 0.93 1.38 1.32 2.44 Experiment 6 1.42 12.27 0.89 1.42 1.44 2.32 Experiment 7 0 0 0 0 0 0 Experiment 8 0 0 0 0 0 0 Experiment 9 0 0 0 0 0 0 Experiment 10 0 0 0 0 0 0 Experiment 11 0 0 0 0 0 0 Experiment 12 0 0 0 0 0 0

[0111] Table 4 Test results of steel in Example 2

[0112]

[0113]

[0114] It can be seen from Tables 3 and 4 that the reinforcement layer in the present application can be applied to a variety of steel substrates, and the corrosion resistance of the steel with the reinforcement layer is improved; at the same time, experiments 7-12 did not have a reinforcement layer. After the same vibration wear resistance test, obvious scratches and even obvious pits appeared on the surface, affecting its use. It can be seen that the setting of the reinforcement layer enhances the wear resistance of the steel; the bonding performance between the reinforcement layer and different types of steel substrates is excellent, the overall reliability of the steel is good, and it is conducive to the use of different types of steel.

[0115] Example 3

[0116] Experiment 1

[0117] Same as Experiment 1 in Example 1.

[0118] Experiment 2

[0119] The process is similar to Experiment 1, except that the cobalt layer is replaced by a nickel layer, and the cobalt-phosphorus alloy layer is replaced by a nickel-phosphorus alloy layer.

[0120] The steel obtained in Experiment 1-2 was subjected to a neutral salt spray test, adhesion test, vibration wear test, load wear test, and hot and cold shock test using the test method in Example 1. The results showed that the test results of the two were similar. Therefore, the use of a metal base layer containing at least one of nickel and cobalt elements and a phosphorus alloy layer can ensure the performance of the overall steel structure.

[0121] Example 4

[0122] Experiment 1

[0123] Same as Experiment 1 in Example 1.

[0124] Experiment 2

[0125] The experiment is similar to Experiment 1, except that a diamond-like carbon layer is formed on the surface of the tungsten carbide layer by deposition, and the thickness of the diamond-like carbon layer is 1.51 μm.

[0126] The test method in Example 1 was used to perform surface hardness testing, neutral salt spray testing, adhesion testing, vibration wear resistance testing, load wear resistance testing, and hot and cold shock testing on the steels obtained in Experiments 1-2. The results showed that the surface hardness of the steel obtained in Experiment 2 was greater than that of the steel obtained in Experiment 1, and the results of the neutral salt spray test, adhesion testing, vibration wear resistance testing, load wear resistance testing, and hot and cold shock testing of the two were similar. Therefore, the reinforcement layer with a diamond-like layer can further improve the surface hardness of the steel, while allowing the steel to maintain excellent wear resistance and corrosion resistance, and the internal bonding strength of the steel is good, which is conducive to the use of the steel.

[0127] Example 5

[0128] Experiments 1-5

[0129] It is substantially the same as Experiment 1 in Example 1, except that the thickness of each layer in the reinforcement layer is different.

[0130] The thickness of each layer in the steel materials produced in Experiments 1-5 was tested using the method in Example 1, and the results are shown in Table 5. The steel materials produced in Experiments 1-5 were subjected to neutral salt spray testing, adhesion testing, vibration wear resistance testing, load wear resistance testing, and thermal shock testing using the test methods in Example 1, and the results are shown in Table 6.

[0131] Table 5 Thickness of each layer in the reinforcement layer obtained in Experiments 1-5 in Example 5

[0132]

[0133]

[0134] Table 6 Test results of steel in Example 5

[0135] Neutral salt spray Adhesion Vibration wear resistance / h Load-bearing and wear-resistant Hot and cold shock Experiment 1 48h pass 2B 2 Large area of ​​white Normal appearance Experiment 2 8h pass 4B 4 White edges Normal appearance Experiment 3 48h pass 2B 1 Large area of ​​white Membrane rupture Experiment 4 48h pass 2B 3 Large area of ​​white Membrane rupture Experiment 5 48h pass 5B 1 Large area of ​​white Normal appearance

[0136] It can be seen from Table 5 and Table 6 in combination with Table 1 and Table 2 that the absence of any one of the metal base layer, phosphorus alloy layer, chromium layer, chromium-tungsten carbide composite layer, and tungsten carbide layer in the reinforcement layer will affect the performance of the steel, such as corrosion resistance, wear resistance, and the bonding performance between the reinforcement layer and the steel substrate, not to mention the absence of multiple layers therein; therefore, the reinforcement layer provided by the present application having a metal base layer, a phosphorus alloy layer, a chromium layer, a chromium-tungsten carbide composite layer, and a tungsten carbide layer can improve the wear resistance and corrosion resistance of the steel, while the bonding strength between the reinforcement layer and the steel and between the internal layers of the reinforcement layer is high and the reliability is good, thereby ensuring the use of the steel.

[0137] The above is a detailed introduction to the contents provided in the implementation mode of the present application. This article explains and illustrates the principles and implementation modes of the present application. The above explanation is only used to help understand the method and core idea of ​​the present application. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation mode and application scope. In summary, the contents of this specification should not be understood as limiting the present application.

Claims

1. A steel material, characterized in that: The invention comprises a steel substrate and a reinforcement layer sequentially arranged on the surface of the steel substrate, wherein the reinforcement layer comprises a metal primer layer, a phosphorus alloy layer, a chromium layer, a chromium-tungsten carbide composite layer and a tungsten carbide layer sequentially arranged on the surface of the steel substrate, the metal primer layer comprises at least one of nickel and cobalt elements, the phosphorus alloy layer comprises at least one of nickel and cobalt elements, the metal primer layer has a thickness of 1 μm to 2 μm, the phosphorus alloy layer has a thickness of 5 μm to 15 μm, the chromium-tungsten carbide composite layer has a thickness of 0.7 μm to 1.7 μm, and the tungsten carbide layer has a thickness of 1.7 μm to 2.5 μm, the chromium layer comprises a first chromium film and a second chromium film arranged between the first chromium film and the chromium-tungsten carbide composite layer, the first chromium film is formed by electroplating, and the second chromium film is formed by deposition, the first chromium film has a thickness of 0.3 μm to 1.5 μm, and the second chromium film has a thickness of 0.1 μm to 1.5 μm.

2. The steel material according to claim 1, wherein The reinforcement layer further comprises a diamond-like carbon layer provided on a surface of the tungsten carbide layer facing away from the chromium-tungsten carbide composite layer; The thickness of the diamond-like carbon layer is 1 μm to 3 μm.

3. The steel material according to claim 1, wherein: The steel substrate has a first surface and a second surface that are opposite to each other, and the reinforcement layer is arranged on the first surface and the second surface.

4. A method for preparing steel, characterized in that: include: A metal primer layer, a phosphorus alloy layer, a chromium layer, a chromium-tungsten carbide composite layer and a tungsten carbide layer are sequentially formed on the surface of a steel substrate to produce a steel material, wherein the metal primer layer includes at least one of nickel and cobalt elements, the phosphorus alloy layer includes at least one of nickel and cobalt elements, the thickness of the metal primer layer is 1 μm to 2 μm, the thickness of the phosphorus alloy layer is 5 μm to 15 μm, the thickness of the chromium-tungsten carbide composite layer is 0.7 μm to 1.7 μm, and the thickness of the tungsten carbide layer is 1.7 μm to 2.5 μm. The chromium layer includes a first chromium film and a second chromium film arranged between the first chromium film and the chromium-tungsten carbide composite layer, the first chromium film is formed by electroplating, and the second chromium film is formed by deposition, the thickness of the first chromium film is 0.3 μm to 1.5 μm, and the thickness of the second chromium film is 0.1 μm to 1.5 μm.

5. The preparation method according to claim 4, wherein Also includes: forming the metal base layer, the phosphorus alloy layer and the first chromium film in sequence on the surface of the steel substrate by electroplating; The second chromium film, the chromium-tungsten carbide composite layer and the tungsten carbide layer are sequentially formed on the surface of the first chromium film by a deposition method.

6. The preparation method according to claim 5, wherein When the metal base layer is formed by the electroplating method, the cobalt content in the electroplating solution is 30 g / L to 60 g / L, the voltage is 5 V to 7 V, and the time is 110 s to 130 s; When the phosphorus alloy layer is formed by the electroplating method, the cobalt content in the electroplating solution is 20 g / L to 70 g / L, the pH value is 2 to 4, the voltage is 4 V to 5 V, the temperature is 65° C. to 75° C., and the time is 560 s to 640 s; When the first chromium film is formed by the electroplating method, the chromic anhydride content in the electroplating solution is 250g / L to 350g / L, the temperature is 35°C to 45°C, and the current density is 30A / dm 2 Up to 60A / dm 2 .

7. An electronic equipment structural component, characterized in that: The material of the electronic equipment structural component includes the steel material described in any one of claims 1 to 3 or the steel material produced by the preparation method described in any one of claims 4 to 6.

8. An electronic device, characterized in that: Including the electronic equipment structural component according to claim 7.

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