Coating material for improving bending strength of flexible ultra-thin glass and coating method thereof

Abstract

The invention discloses a coating material for improving bending strength of flexible ultra-thin glass and a coating method thereof. According to the invention, the enhanced bonding layer functional composite film material is prepared from various rare earth oxide materials and inorganic metal oxides according to a certain ratio, so that the balance of the hardness and toughness of the film material is realized, and the adhesive force of the film material is improved through covalent bond combination of the rare earth oxide materials, the inorganic metal oxides and amorphous silicon on the surface of flexible glass; the ratio of all the materials is optimized, the difference between the coefficient of thermal expansion of the flexible glass and the coefficient of thermal expansion of the film is reduced, stress is effectively reduced, and the firmness of the film is enhanced. The bending strength, the fracture toughness, the impact resistance, the friction resistance, the folding resistance and the like of the coated flexible glass are remarkably improved. The laser beam is used for rapidly heating and cooling the film layer, so that the microstructure of the film layer is improved, the stress is eliminated, the bending strength and the fracture toughness are improved, and the compactness of the film layer is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible glass strengthening, and particularly relates to a coating material for improving the bending strength of flexible ultra-thin glass and a coating method thereof. Background Art

[0002] Flexible ultra-thin glass is widely used in fields such as flexible displays, photovoltaic modules, and covers of electronic devices. Due to the presence of microcracks on its surface, the strength of flexible ultra-thin glass is insufficient. The inherent brittleness and low strength of flexible ultra-thin glass easily lead to the risk of breakage. Flexible ultra-thin glass is a special glass material with extremely high flexibility and extremely thin thickness. Its thickness is usually between 0.1 mm and 1 mm, and can even reach a thinner level. This kind of glass adopts special manufacturing processes, such as the overflow down-draw method or chemical strengthening methods, so that while maintaining the inherent transparency and hardness of the glass, it has excellent bending and folding capabilities without breaking. Flexible ultra-thin glass has broad application prospects in wearable devices, flexible displays, smart windows, and other fields with strict requirements for weight and thickness. It can be combined with flexible electronic components to manufacture bendable, rollable, and even foldable electronic devices, greatly expanding the possibilities of electronic product design.

[0003] However, at present, the traditional ion-exchange chemical strengthening process is likely to cause warping and deformation to flexible ultra-thin glass, and the thickness is limited. Physical coatings (such as single-layer SiO2, TiO2) have defects such as poor adhesion or poor stress matching, and are prone to peeling. The organic coating process has defects such as poor high-temperature resistance and cannot meet the requirements of high-temperature processes.

[0004] Therefore, there is an urgent need to develop a new type of coating material and coating method for improving the bending strength of flexible ultra-thin glass. Summary of the Invention

[0005] The purpose of the present invention is to provide a coating material for improving the bending strength of flexible ultra-thin glass and a coating method thereof in order to solve the above-mentioned problems.

[0006] The technical solution adopted by the present invention is as follows:

[0007] In a preferred embodiment,

[0008] In a preferred embodiment,

[0009] In a preferred embodiment,

[0010] In a preferred embodiment,

[0011] In a preferred embodiment,

[0012] In a preferred embodiment,

[0013] In a preferred embodiment,

[0014] In a preferred embodiment,

[0015] In a preferred embodiment,

[0016] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0017] 1. In the present invention, an enhanced bonding layer functional composite film material is prepared by mixing various rare earth oxide materials and inorganic metal oxides in a certain ratio, achieving the balance between the hardness and toughness of the film material. The adhesion of the film material is improved through the covalent bond combination of rare earth oxide materials, inorganic metal oxides and amorphous silicon on the surface of flexible glass. By optimizing the ratio of each material, the difference in the thermal expansion coefficients of flexible glass and the film layer is reduced, effectively reducing the generation of stress and enhancing the firmness of the film layer.

[0018] 2. In the present invention, a multi-layer film system stacking electroplating process is adopted to further optimize and improve the denseness of the film layer. After coating, the flexural strength, fracture toughness, impact resistance, friction resistance times, folding resistance performance, etc. of the flexible glass are significantly improved. The film layer is rapidly heated and cooled by a laser beam to improve the microstructure of the film layer, eliminate stress, increase the flexural strength and fracture toughness, and enhance the denseness of the film layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a process flow chart of the film material preparation of the present invention;

[0020] Figure 2 is a coating structure diagram of the multi-layer film system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] Example:

[0023] Referring to Figure 1-2 , a coating material for improving the flexural strength of flexible ultra-thin glass, the coating material includes: 35-50% of yttrium oxide Y2O3, 20-35% of aluminum oxide Al2O3, 15-30% of zirconium dioxide ZrO2, and 10-25% of titanium pentoxide Ti3O5.

[0024] A coating material for improving the flexural strength of flexible ultra-thin glass with a multi-layer film system structure coating (electroplating in turn from the glass substrate outwards in a coating machine) includes:

[0025] ① First coating layer: Enhanced bonding layer functional composite film material. The main materials include 35 - 50% yttrium oxide Y2O3, 20 - 35% aluminum oxide Al2O3, 15 - 30% zirconium dioxide ZrO2, and 10 - 25% titanium pentoxide Ti3O5. The film layer thickness is 30 - 50 nm, which can enhance the film - substrate bonding force, achieve the balance of hardness and toughness through the composite material layer, and improve the adhesion through the covalent bond combination of the underlying rare - earth oxide material, inorganic metal oxide and amorphous silicon on the surface of the flexible glass.

[0026] ② Second coating layer: Buffer layer functional film material. The main material is silicon nitride Si3N4. The film layer thickness is 100 - 150 nm, which relieves the internal stress caused by the difference in thermal expansion coefficients of different materials and also enhances the flexural strength of the film layer.

[0027] ③ Third coating layer: Protective layer film material. The main material is fluorinated diamond - like carbon film (F - DLC), with a thickness of 30 - 50 nm, which improves the hydrophobicity and wear resistance of the film layer.

[0028] The coating method includes the following steps:

[0029] S1: Mix yttrium oxide, aluminum oxide, zirconium dioxide and titanium pentoxide in proportion, and prepare the enhanced bonding layer composite film material through ball - milling, static pressing and high - temperature sintering;

[0030] S2: Perform ion - source bombardment pretreatment on the flexible ultra - thin glass substrate to clean and activate the surface;

[0031] S3: Deposit the enhanced bonding layer in a vacuum coating machine, with a thickness of 30 - 50 nm;

[0032] S4: Deposit the buffer layer, using silicon nitride Si3N4 material, with a thickness of 100 - 150 nm;

[0033] S5: Deposit the protective layer, using fluorinated diamond - like carbon film, with a thickness of 30 - 50 nm;

[0034] S6: Perform dynamic - regulation laser annealing on the coated substrate. By real - time monitoring the change of the film layer temperature, adaptively adjust the laser power and scanning rate to eliminate stress and optimize the microstructure;

[0035] S7: Use in - situ spectroscopic analysis technology to verify the film layer density and interface bonding state;

[0036] S8: Complete the performance verification through flexural strength, fracture toughness and wear resistance tests.

[0037] In the step S1, yttrium oxide, aluminum oxide, zirconium dioxide, and titanium pentoxide are mixed in a mass percentage ratio of 35%-50%, 20%-35%, 15%-30%, and 10%-25%. Among them, yttrium oxide serves as the main reinforcing phase, aluminum oxide is used to balance hardness and expansion coefficient, zirconium dioxide adjusts stress, and titanium pentoxide enhances the interfacial bonding force. The mixed material is ground in a ball mill to a particle size less than 50 nanometers and a uniformity higher than 98%. Subsequently, it is pressed into a block under a static pressure of 300-330 kg / cm², broken into 1-3 mm particles, and then placed in a high-temperature sintering furnace at 1350-1400 °C for sintering for 16-20 hours to enable full reaction of each component and form a dense composite film material.

[0038] In the step S2, the flexible ultra-thin glass substrate is placed in a vacuum coating machine, and the vacuum is pumped to an extremely high vacuum environment of 7.5×10 -4 to 8.5×10 -4 Pa. The ion source bombardment technology is used to clean and activate the glass surface for 2.5-3 minutes. This step removes surface contaminants through ion bombardment and forms a micro-rough structure, significantly improving the physical bonding strength between the subsequent film layer and the substrate.

[0039] In the step S3, the first layer of enhanced bonding layer composite film material is deposited on the surface of the pretreated substrate, and the thickness is controlled within the range of 30-50 nanometers. During the deposition process, the vacuum degree is kept stable at 7.5×10 -4 to 8.5×10 -4 Pa. Through the covalent bond binding mechanism of rare earth oxides and inorganic metal oxides, high adhesion between the film layer and the flexible glass surface is achieved, while balancing the hardness and toughness of the film layer.

[0040] In the step S4, trisilicon tetranitride material is used as the second buffer layer, and a film layer with a thickness of 100-150 nanometers is deposited by vacuum electroplating process. This layer effectively alleviates the thermal stress difference between the film layer and the substrate through the high-temperature stability and moderate thermal expansion coefficient of trisilicon tetranitride, and further enhances the flexural strength and impact resistance of the overall structure.

[0041] In the step S5, the third layer of fluorinated diamond-like carbon film is deposited on the surface of the buffer layer, with a thickness of 30-50 nanometers. This layer endows the coated surface with excellent scratch resistance by utilizing the high hydrophobicity and wear resistance of the fluorinated diamond-like carbon film, while maintaining the high light transmittance of the glass substrate, ensuring its applicability in the field of optical display.

[0042] In step S6, the coated substrate is subjected to laser annealing treatment. An integrated temperature sensor is used to monitor the temperature distribution of the film layer in real time, and the laser power and scanning rate are dynamically adjusted based on the feedback data. During the annealing process, the laser beam rapidly heats and cools the film layer at a scanning speed of 5-10 millimeters per second, precisely eliminating residual stress and optimizing the grain boundary structure, ultimately increasing the film layer density to over 98%.

[0043] In step S7, in-situ spectroscopic analysis technology is used to non-destructively detect the interface bonding state and film layer density after coating. Data is collected in real time through ultraviolet-visible light spectroscopy and Raman spectroscopy to verify the chemical bonding strength between the film layer and the substrate and the absence of micro-crack defects inside the film layer, ensuring that the process quality meets the design requirements.

[0044] In step S8, the flexural strength is measured through a three-point bending test, the impact resistance is evaluated through a standard falling ball impact test, the wear resistance times are detected through a reciprocating friction test, and the mechanical properties of the film layer are quantified in combination with a microhardness tester and a fracture toughness tester. The test results show that the flexural strength of the coated flexible glass is increased to 685-720 MPa, the fracture toughness reaches 1.24-1.32 kJ / m², and the number of friction resistance times exceeds 150,000 times, and the comprehensive performance meets the application requirements of high-end flexible electronic devices.

[0045] Example 1:

[0046] 1. Preparation of the enhanced bonding layer functional composite film material: The composite film material is prepared according to the following ratio (wt%): yttrium oxide Y2O3 45%, aluminum oxide Al2O3 25%, zirconium dioxide ZrO2 20%, titanium pentoxide Ti3O5 10%. The above raw materials are prepared into an enhanced bonding layer functional composite film material according to a certain ratio, ground and mixed in a ball mill, with a uniformity of over 98% and a particle size of below 50 nm. Then it is sent to a static press and pressed into a block under a high pressure of 300 Kg / cm2, and then broken into particles of 1-3 mm and sintered in a high-temperature sintering furnace at 1400 °C for 16 hours to allow full reaction and bonding between the component materials, generating an enhanced functional coating material, that is, the enhanced bonding layer functional composite film material is made.

[0047] 2. Then start to complete the electroplating of the multi-layer film system in sequence:

[0048] ① First, place the cleaned flexible glass on the fixed bracket of the vacuum coating machine, set the vacuum degree to 8.5×10-4 Pa, bombard with the ion source for 2.5 minutes, and then vacuum electroplate the first layer of enhanced bonding layer functional composite film material with a coating thickness of 50 nm.

[0049] ② Then start electroplating the second layer of buffer layer functional film material with a coating thickness of 120 nm.

[0050] ③Finally, electroplate the third layer of protective layer, fluorinated diamond-like carbon (F-DLC) film material, with a coating thickness of 30 nm.

[0051] 3. Finally, there is laser annealing: After the multi-layer coating is completed, it is sent into a laser annealing furnace for rapid laser annealing to eliminate stress, thus completing the coating operation to increase the strength of the flexible glass.

[0052] Example 2:

[0053] 1. Preparation of the enhanced adhesion layer composite functional film material: Prepare the composite film material according to the following ratio (wt%): yttrium oxide Y2O3 40%, aluminum oxide Al2O3 26%, zirconium dioxide ZrO2 22%, titanium pentoxide Ti3O5 12%. The above raw materials are prepared into an enhanced adhesion layer functional composite film material according to a certain ratio, ground and mixed in a ball mill, with a uniformity of more than 98% and a particle size of less than 50 nm. Then it is sent to a static press and pressed into a block under a high pressure of 320 Kg / cm2, and then crushed into particles of 1 - 3 mm and sintered in a high-temperature sintering furnace at 1380 °C for 18 hours to allow full reaction and bonding between the component materials, generating an enhanced functional coating material, that is, the enhanced adhesion layer functional composite film material is prepared.

[0054] 2. Then start to complete the electroplating of the multi-layer film system in sequence:

[0055] ①First, place the cleaned flexible glass on the fixed bracket of the vacuum coating machine, set the vacuum degree to 8×10-4 Pa, bombard with the ion source for 3 minutes, and then electroplate the first layer of enhanced adhesion layer functional composite film material with a coating thickness of 45 nm.

[0056] ②Then start to electroplate the second layer of buffer layer functional film material with a coating thickness of 150 nm.

[0057] ③Finally, electroplate the third layer of protective layer, fluorinated diamond-like carbon (F-DLC) film material, with a coating thickness of 40 nm.

[0058] 3. Finally, there is laser annealing: After the multi-layer coating is completed, it is sent into a laser annealing furnace for rapid laser annealing to eliminate stress, thus completing the coating operation to increase the strength of the flexible glass.

[0059] Example 3:

[0060] 1. Preparation of enhanced bonding layer functional composite film material: Prepare the composite film material according to the following ratio (wt%): 38% yttrium oxide Y2O3, 24% aluminum oxide Al2O3, 22% zirconium dioxide ZrO2, and 16% titanium pentoxide Ti3O5. The above raw materials are prepared into an enhanced bonding layer functional composite film material according to a certain ratio, ground and mixed in a ball mill, with a uniformity of over 98% and a particle size of below 50 nm. Then it is sent to a static press and pressed into a block under a high pressure of 330 Kg / cm2, and then broken into particles of 1 - 3 mm, and sintered in a high-temperature sintering furnace at 1360 °C for 20 hours to fully react and bond between the component materials, generating an enhanced functional coating material, that is, the enhanced bonding layer functional composite film material is prepared.

[0061] 2. Then start to complete the electroplating of the multi-layer film system in sequence:

[0062] ① First, place the cleaned flexible glass on the fixed bracket of the vacuum coating machine, set the vacuum degree to 7.5×10-4 Pa, bombard with the ion source for 3 minutes, and then electroplate the first layer of enhanced bonding layer functional composite film material with a coating thickness of 40 nm.

[0063] ② Then start to electroplate the second layer of buffer layer functional film material with a coating thickness of 135 nm.

[0064] ③ Finally, electroplate the third layer of protective layer fluorinated diamond-like carbon (F-DLC) film material with a coating thickness of 35 nm.

[0065] Finally, it is laser annealing: After the multi-layer coating is completed, it is sent into a laser annealing furnace for rapid laser annealing to eliminate stress, that is, the coating operation for increasing the strength of the flexible glass is completed.

[0066] The specific structure is shown in the following table:

[0067] Performance data comparison table of implementation examples

[0068] Performance index Uncoated flexible glass Example 1 Example 2 Example 3 Flexural strength (MPa) 512 720 706 685 Microhardness (GPa) 6.0 8.2 8.1 7.8 <![CDATA[Fracture toughness (KJ / m 2 )]]> 0.70 1.32 1.28 1.24 Transmittance (550nm) 92.8％ 91.5％ 90.8％ 91.2％ Impact resistance (falling ball test) More than 3 times More than 4 times More than 4 times More than 4 times Number of friction resistance times (times) 100000 150000 158000 155000 Number of anti-folding times (10,000 times) 20 26 23 25

[0069] It can be known from the above that: in the present invention, an enhanced bonding layer functional composite film material is prepared by mixing various rare earth oxide materials and inorganic metal oxides according to a certain ratio, achieving the balance between the hardness and toughness of the film material, and enhancing the film material adhesion through the covalent bond combination of rare earth oxide materials, inorganic metal oxides and amorphous silicon on the surface of the flexible glass; optimizing the ratio of each material, reducing the difference in the thermal expansion coefficients of the flexible glass and the film layer, effectively reducing the generation of stress, and enhancing the firmness of the film layer.

[0070] In the present invention, a multi-layer film system superposition electroplating process is adopted to further optimize and improve the film layer density. After coating, the flexural strength, fracture toughness, impact resistance, friction resistance times, folding resistance performance, etc. of the flexible glass are significantly improved. The film layer is rapidly heated and cooled by a laser beam to improve the microstructure of the film layer, eliminate stress, increase the flexural strength and fracture toughness, and enhance the density of the film layer.

[0071] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0072] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coating material for improving the bending strength of flexible ultra-thin glass, characterized in that: The coating material comprises: 35-50% yttrium oxide Y2O3, 20-35% aluminum oxide Al2O3, 15-30% zirconium dioxide ZrO2, and 10-25% titanium pentoxide Ti3O5.

2. A method for improving the bending strength of flexible ultra-thin glass according to claim 1, characterized in that: The coating method comprises the following steps: S1: Yttrium oxide, aluminum oxide, zirconium dioxide and titanium pentoxide are mixed in proportion, and a reinforced bonding layer composite film material is prepared by ball milling, static pressing and high-temperature sintering; S2: pre-treating the flexible ultra-thin glass substrate by ion source bombardment to clean and activate the surface; S3: Depositing an enhanced bonding layer in a vacuum coating machine in sequence, with a thickness of 30-50 nm; S4: depositing a buffer layer using silicon nitride material with a thickness of 100-150 nm; S5: depositing a protective layer, using a fluorine-doped diamond-like carbon film with a thickness of 30-50 nm; S6: Dynamically control laser annealing of the coated substrate, monitor the temperature change of the film layer in real time, adaptively adjust the laser power and scanning rate, eliminate stress and optimize the microstructure; S7: Using in-situ spectral analysis technology to verify the film density and interface bonding state; S8: Performance verification is completed through flexural strength, fracture toughness and wear resistance tests.

3. The coating method of the coating material for improving the bending strength of flexible ultra-thin glass according to claim 1, characterized in that: In the step S1, yttrium oxide, aluminum oxide, zirconium dioxide and titanium pentoxide are mixed in a mass percentage of 35%-50%, 20%-35%, 15%-30% and 10%-25%, wherein yttrium oxide is used as the main reinforcing phase, aluminum oxide is used to balance hardness and expansion coefficient, zirconium dioxide is used to adjust stress, and titanium pentoxide is used to enhance interface bonding strength; the mixed material is ground in a ball mill to a particle size of less than 50 nanometers and a uniformity of more than 98%, and then pressed into a block under a static pressure of 300-330 kilograms per square centimeter, crushed into 1-3 mm particles, and then placed in a high-temperature sintering furnace at 1350-1400 degrees Celsius for sintering for 16-20 hours.

4. The coating method of the coating material for improving the bending strength of flexible ultra-thin glass according to claim 1, characterized in that: In step S2, the flexible ultra-thin glass substrate is placed in a vacuum coating machine and evacuated to 7.5×10 -4 Up to 8.5×10 -4 In an extremely high vacuum environment of 1000 Pa, the glass surface is cleaned and activated for 2.5-3 minutes using ion source bombardment technology.

5. The coating method of the coating material for improving the bending strength of flexible ultra-thin glass according to claim 1, characterized in that: In step S3, a first layer of enhanced bonding layer composite film material is deposited on the surface of the pretreated substrate, and the thickness is controlled within the range of 30-50 nanometers; the vacuum degree is kept stable at 7.5×10 -4 Up to 8.5×10 -4 Through the covalent bond mechanism of rare earth oxides and inorganic metal oxides, the film layer achieves high adhesion to the flexible glass surface while balancing the hardness and toughness of the film layer.

6. The coating method of the coating material for improving the bending strength of flexible ultra-thin glass according to claim 1, characterized in that: In step S4, silicon nitride material is used as the second buffer layer, and a film layer with a thickness of 100-150 nanometers is deposited by a vacuum electroplating process; this layer effectively alleviates the thermal stress difference between the film layer and the substrate through the high temperature stability and moderate thermal expansion coefficient of silicon nitride, and further enhances the bending strength and impact resistance of the overall structure.

7. The coating method of the coating material for improving the bending strength of flexible ultra-thin glass according to claim 1, characterized in that: In the step S5, a third layer of fluorine-doped diamond-like carbon film is deposited on the surface of the buffer layer with a thickness of 30-50 nanometers; this layer utilizes the high hydrophobicity and wear resistance of the fluorine-doped diamond-like carbon film to give the coated surface excellent scratch resistance, while maintaining the high light transmittance of the glass substrate to ensure its suitability for the field of optical display.

8. The coating method of the coating material for improving the bending strength of flexible ultra-thin glass according to claim 1, characterized in that: In step S6, the coated substrate is subjected to laser annealing, an integrated temperature sensor is used to monitor the temperature distribution of the film layer in real time, and the laser power and scanning rate are dynamically adjusted based on feedback data; during the annealing process, the laser beam rapidly heats and cools the film layer at a scanning speed of 5-10 mm per second.

9. The coating method of the coating material for improving the bending strength of flexible ultra-thin glass according to claim 1, characterized in that: In step S7, in-situ spectral analysis technology is used to perform non-destructive testing on the interface bonding state and film density after coating; real-time data is collected through ultraviolet-visible light spectroscopy and Raman spectroscopy to verify the chemical bonding strength between the film layer and the substrate and the absence of microcrack defects inside the film layer, thereby ensuring that the process quality meets the design requirements.

10. The coating method of the coating material for improving the bending strength of flexible ultra-thin glass according to claim 1, characterized in that: In step S8, the bending strength is determined by a three-point bending test, the impact resistance is evaluated by a standard falling ball impact test, the wear resistance is detected by a reciprocating friction test, and the mechanical properties of the film layer are quantified in combination with a microhardness tester and a fracture toughness tester.

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