Strengthened microcrystalline glass, glass device and electronic device

Abstract

The present invention belongs to the technical field of lithium aluminum silicon glass-ceramics, and specifically relates to a strengthened glass-ceramic, a glass device, and an electronic device with excellent single-unit strength and excellent drop resistance. The strengthened glass-ceramic comprises a compressive stress layer and a tensile stress layer, and the main crystalline phase of the strengthened glass-ceramic comprises a petalite crystal phase and a lithium disilicate crystal phase. The strengthened glass-ceramic satisfies the following conditions: surface CS is 500-1000 MPa; 50.00> surface CS / |CT_AV|≥17.00 and |C T_AV|≥30MPa, where |CT_AV| is the absolute value of the average tensile stress in the tensile stress layer, in MPa; |CT_CV|≥50MPa, where |CT_CV| is the absolute value of the maximum tensile stress in the tensile stress layer, in MPa; 0.25t≥DOL_0≥0.15t, where DOL_0 refers to the depth of the compressive stress layer, and t is the thickness of the strengthened glass-ceramics; and the surface K2O concentration of the strengthened glass-ceramics is 7.00-15.00wt%. The strengthened glass-ceramics of the present invention have excellent resistance to non-contact surface cracking, excellent resistance to contact surface cracking, and excellent weather resistance.

Description

[0001] This application is a divisional application of the patent application with application number 202210869330.9, invention name “A strengthened microcrystalline glass, glass device and electronic device”, filed on July 22, 2022. Technical Field

[0002] The present invention belongs to the technical field of lithium aluminum silicon microcrystalline glass, and specifically relates to a reinforced microcrystalline glass and glass devices and electronic equipment with excellent single-body strength and excellent drop resistance. Background Art

[0003] With the advent of the smart age, electronic devices such as mobile phones, tablets, and watches have become an indispensable part of daily life. Most of these devices are damaged by screen shattering, so the strength of cover glass needs to be improved urgently. Cover glass damage often occurs when a smartphone is dropped or impacted with another object. Generally speaking, there are two main types of damage: cracking on the contact surface and cracking on the non-contact surface.

[0004] Contact surface cracking refers to the situation when the glass surface collides with a sharp object with greater hardness (such as fine sand, cement, and pebbles), and the glass surface is partially damaged, forming a hemispherical crack extension source at the damage point. The collision energy is partially attenuated, and the remaining energy further expands. When the compressive stress level on the glass surface is not enough to offset the remaining energy, the crack extension will pass through the glass surface area. When the longitudinal crack passes through the depth of the compressive stress layer and reaches the tensile stress layer area, the crack will rapidly expand in the tensile stress area, causing the crack to penetrate the entire glass, thereby causing the glass to break and shatter into various small pieces, such as Figure 1 .

[0005] Non-contact surface cracking refers to when a blunt object or an object with a hardness lower than that of the glass hits the glass surface, the contact surface will be squeezed, and the back of the corresponding contact point will be stretched due to the deformation of the glass. When the collision force is greater than the maximum compressive stress on its surface, the glass will be damaged. Figure 2 .

[0006] Glass-ceramics with petalite and lithium disilicate as the main crystalline phases has a crystallinity of over 70wt% and a transmittance close to that of commonly used lithium aluminosilicate glass. At the same time, it can be chemically strengthened in a salt bath / molten salt to further improve its anti-extrusion, impact resistance, and drop resistance properties, and has received widespread attention in the cover industry.

[0007] At present, the research on the damage resistance of microcrystalline glass / microcrystalline cover glass with petalite and lithium disilicate as the main crystal phases mainly focuses on improving CT and DOL_0, and improving the damage resistance of glass by suppressing cracking on the contact surface. There is less research on suppressing cracking on the non-contact surface to improve the damage resistance of glass. The existing microcrystalline glass of this type has the ability to resist non-contact surface cracking and needs to be further improved.

[0008] Furthermore, current research focuses primarily on improving / optimizing the mechanical properties of this type of glass-ceramics, often overlooking other properties, such as weather resistance. Application CN111867993A mentions that after undergoing ion exchange chemical strengthening, the resulting strengthened glass products tend to exhibit low chemical durability, which can significantly impact the use of the glass products in specialized environments. According to the patent application, the solution employed to improve chemical durability involves using a specific strengthening method to control the absolute value of the maximum surface compressive stress to 1.8-2.2 times the absolute value of the maximum central tensile stress, and to control the surface CS to no more than 350 MPa. Summary of the Invention

[0009] The purpose of the present invention is to overcome the defect of the prior art microcrystalline glass that its resistance to non-contact surface cracking needs to be improved, and to provide a strengthened microcrystalline glass, glass device and electronic equipment, which has excellent resistance to non-contact surface cracking and excellent resistance to contact surface cracking.

[0010] The present inventors have discovered that surface CS is closely related to the glass's resistance to non-contact surface cracking. A decrease in surface CS reduces the glass's resistance to non-contact surface cracking, making it more susceptible to non-contact surface cracking and damage. Improving the non-contact surface cracking resistance of this type of glass-ceramics while maintaining its other excellent properties, such as resistance to contact surface cracking (e.g., resistance to sandpaper drops) and weather resistance, remains an urgent challenge. The present inventors conducted further research and proposed the present invention.

[0011] To achieve the above objectives, in a first aspect, the present invention provides a strengthened glass-ceramic having excellent resistance to non-contact surface cracking, wherein the strengthened glass-ceramic has a compressive stress layer formed by chemical strengthening on the surface, and has a tensile stress layer inside that can achieve force balance with the compressive stress layer, that is, the strengthened glass-ceramic includes a compressive stress layer and a tensile stress layer, and the main crystalline phase of the strengthened glass-ceramic includes a petalite crystalline phase and a lithium disilicate crystalline phase, and the strengthened glass-ceramic satisfies:

[0012] Surface CS ≥ 400 MPa;

[0013] Surface CS / |CT_AV|≥17.00, |CT_AV| is the absolute value of the average tensile stress in the tensile stress layer, in MPa;

[0014] DOL_0≥0.15t, DOL_0 refers to the depth of the compressive stress layer, and t is the thickness of the strengthened microcrystalline glass.

[0015] Further preferably, the surface CS of the strengthened glass-ceramics is ≥500 MPa, preferably, the surface CS is 550-1000 MPa.

[0016] Further preferably, the |CT_AV| of the strengthened glass-ceramics is ≥30 MPa, preferably, |CT_AV| is 35-60 MPa.

[0017] Further preferably, in the strengthened glass-ceramics, 50.00≥surface CS / |CT_AV|≥17.00.

[0018] Further preferably, in the strengthened glass-ceramics, 0.25t≥DOL_0≥0.15t.

[0019] In some preferred embodiments of the present invention, the strengthened glass-ceramics further satisfies: |CT_CV|≥50MPa, where |CT_CV| is the absolute value of the maximum tensile stress in the tensile stress layer.

[0020] More preferably, |CT_CV| is 55-80 MPa.

[0021] In some preferred embodiments of the present invention, the surface K2O concentration of the strengthened glass-ceramics is ≥7.00 wt%.

[0022] More preferably, the surface K2O concentration of the strengthened glass-ceramics is 7.00-15.00 wt%.

[0023] In some preferred embodiments of the present invention, in the strengthened glass-ceramics, the total weight of the petalite crystal phase and the lithium disilicate crystal phase accounts for no less than 71.00 wt %.

[0024] More preferably, in the strengthened glass-ceramics, the total weight of the petalite crystal phase and the lithium disilicate crystal phase accounts for 71.00-90.00 wt %.

[0025] More preferably, in the strengthened glass-ceramics, the ratio of the petalite crystal phase to the lithium disilicate crystal phase is (0.9-1.1):1.

[0026] More preferably, in the strengthened glass-ceramics, the average size of the grains is ≤100 nm, preferably 10-50 nm, and more preferably 15-25 nm.

[0027] In some preferred embodiments of the present invention, the composition of the strengthened microcrystalline glass tensile stress layer includes, in percentage by mass: SiO2: 58.00-76.00%, Al2O3: 6.00-8.00%, P2O5: 2.00-3.00%, ZrO2: 4.00-6.00%, Na2O: 3.00-10.00%, Li2O: 9.00-12.00%, and B2O3: 0-3.00%.

[0028] According to the present invention, preferably, at a thickness of 0.7 mm, the average single-rod static pressure strength of the strengthened glass-ceramics is ≥400N, preferably, the average single-rod static pressure strength is 401-500N.

[0029] According to the present invention, preferably, the tempered microcrystalline glass is subjected to a high temperature and high humidity failure test under the conditions of 85°C and 85% relative humidity, and the high temperature and high humidity failure time thereof is ≥204h. The high temperature and high humidity failure time is the time when spots or fog points that cannot be wiped off appear on the tempered microcrystalline glass under the corresponding high temperature and high humidity conditions.

[0030] According to the present invention, preferably, when the thickness is 0.7 mm, the tempered glass-ceramics is subjected to a sandpaper drop resistance test using 120-grit sandpaper, and the average sandpaper drop resistance height is 1.10-1.50 m.

[0031] According to the present invention, preferably, at a thickness of 0.7 mm, the transmittance of the strengthened micro-ceramic glass for light with a wavelength of 550 nm is not less than 89.00%.

[0032] In a second aspect, the present invention further provides a strengthened microcrystalline glass having excellent resistance to non-contact surface cracking and weather resistance, wherein the strengthened microcrystalline glass has a compressive stress layer formed by chemical strengthening on the surface, and has a tensile stress layer inside that can achieve force balance with the compressive stress layer, that is, the strengthened microcrystalline glass comprises a compressive stress layer and a tensile stress layer, and the strengthened microcrystalline glass comprises a petalite crystal phase and a lithium disilicate crystal phase with a total weight accounting for not less than 71.00wt%; and the strengthened microcrystalline glass satisfies:

[0033] Surface CS ≥ 400 MPa;

[0034] Surface CS / |CT_AV|≥17.00, |CT_AV| is the absolute value of the average tensile stress in the tensile stress layer, in MPa;

[0035] DOL_0≥0.15t, DOL_0 refers to the depth of the compressive stress layer, and t is the thickness of the strengthened glass-ceramic;

[0036] The surface K2O concentration of the strengthened glass-ceramics is ≥7.50 wt%.

[0037] In the second aspect, preferably, the surface CS of the strengthened glass-ceramics is ≥500 MPa, preferably, the surface CS is 550-1000 MPa.

[0038] In the second aspect, preferably, the tempered glass-ceramics has |CT_AV|≥30 MPa, preferably, |CT_AV| is 35-60 MPa.

[0039] In the second aspect, preferably, in the strengthened glass-ceramics, 50.00≥surface CS / |CT_AV|≥17.00.

[0040] In the second aspect, preferably, in the strengthened glass-ceramics, 0.25t≥DOL_0≥0.15t.

[0041] According to some preferred embodiments of the second aspect of the present invention, the strengthened microcrystalline glass further satisfies: |CT_CV|≥50MPa, |CT_CV| is the absolute value of the maximum tensile stress in the tensile stress layer, preferably, |CT_CV| is 55-80MPa.

[0042] According to some preferred embodiments of the second aspect of the present invention, the surface K2O concentration of the strengthened glass-ceramics is 7.50-15.00 wt%.

[0043] According to some preferred embodiments of the second aspect of the present invention, in the strengthened glass-ceramics, the total weight of the petalite crystal phase and the lithium disilicate crystal phase accounts for 71.00-90.00 wt %.

[0044] According to some preferred embodiments of the second aspect of the present invention, in the strengthened glass-ceramics, the ratio of the petalite crystal phase to the lithium disilicate crystal phase is (0.9-1.1):1.

[0045] According to some preferred embodiments of the second aspect of the present invention, in the strengthened glass-ceramics, the average size of the grains is ≤100 nm, preferably 10-50 nm, and more preferably 15-25 nm.

[0046] According to some preferred embodiments of the second aspect of the present invention, the composition of the strengthened microcrystalline glass tensile stress layer includes, in percentage by mass: SiO2: 58.00-76.00%, Al2O3: 6.00-8.00%, P2O5: 2.00-3.00%, ZrO2: 4.00-6.00%, Na2O: 3.00-10.00%, Li2O: 9.00-12.00%, and B2O3: 0-3.00%.

[0047] According to the second aspect of the present invention, preferably, at a thickness of 0.7 mm, the average single-rod static pressure strength of the strengthened glass-ceramics is ≥400N, more preferably, the average single-rod static pressure strength is 401-500N.

[0048] According to the second aspect of the present invention, preferably, the tempered microcrystalline glass is subjected to a high temperature and high humidity failure test under the conditions of 85°C and 85% relative humidity, and its high temperature and high humidity failure time is ≥204h. The high temperature and high humidity failure time is the time when spots or fog points that cannot be wiped off appear on the tempered microcrystalline glass under the corresponding high temperature and high humidity conditions.

[0049] According to the second aspect of the present invention, preferably, when the thickness is 0.7 mm, the tempered glass-ceramic is subjected to a sandpaper drop resistance test using 120-grit sandpaper, and the average sandpaper drop resistance height is 1.10-1.50 m.

[0050] According to the second aspect of the present invention, preferably, at a thickness of 0.7 mm, the transmittance of the strengthened micro-ceramic glass for light with a wavelength of 550 nm is not less than 89.00%.

[0051] In a third aspect, the present invention provides a glass device, wherein the glass device is made of the strengthened microcrystalline glass described in the first aspect or the second aspect.

[0052] In a fourth aspect, the present invention provides an electronic device comprising a cover, wherein the cover comprises the strengthened micro-ceramic glass described in the first aspect or the second aspect.

[0053] Preferably, the electronic device includes but is not limited to at least one of a mobile phone, a display (such as a car display, an aircraft display, etc.), a tablet computer, an electronic watch, a smart wearable (such as a smart bracelet, a smart watch, smart glasses, etc.), and a television.

[0054] After research, the inventors of the present invention found that the stress structure of the micro-ceramics in the prior art is usually characterized by surface CS and CT. However, the micro-ceramics that meet a certain conventional range of surface CS and CT have a low resistance to non-contact surface cracking and cannot meet the requirements. In addition, the relationship between surface CS, CT, etc. and the resistance to non-contact surface cracking is not clear in the prior art. It was further discovered that by making the micro-ceramics with petalite and lithium disilicate as the main crystalline phases meet specific stress characteristics, especially the surface CS / |CT_AV| at a certain level, it is possible to improve the resistance of the micro-ceramics to non-contact surface cracking while ensuring that it meets the requirements for resistance to contact surface cracking. At the same time, combined with the control of the K2O concentration on the surface of the micro-ceramics, it is also possible to solve the problem that the weather resistance of the strengthened micro-ceramics products is not excellent enough.

[0055] The present invention utilizes these findings to provide a strengthened glass-ceramic with a specific surface CS and surface CS to |CT_AV| ratio, and a DOL_0 within the aforementioned specific range. This strengthens the glass-ceramic to possess a specific stress structure, significantly enhancing its resistance to non-contact cracking while also providing excellent resistance to contact cracking. Furthermore, a strengthened glass-ceramic with a surface K2O concentration within a specific range is provided, which also provides excellent weather resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0057] Figure 1 Schematic diagram of the contact surface fracture of strengthened glass-ceramics.

[0058] Figure 2 Schematic diagram of the non-contact surface fracture of strengthened glass-ceramics.

[0059] Figure 3 This is the FSM-6000 test diagram of Example 1 of the present invention.

[0060] Figure 4 This is the DSC test curve diagram of Example 1 of the present invention.

[0061] Figure 5 This is the XRD result diagram of Example 1 of the present invention.

[0062] Figure 6 This is a diagram showing the transmittance test results of Example 1 of the present invention.

[0063] Figure 7 This is a picture of the sample of comparative example 4 in a high temperature and high humidity environment for 24 hours.

[0064] Figure 8 This is a picture of a sample in a high temperature and high humidity environment for 240 hours according to Example 1 of the present invention.

[0065] Figure 9 This is a picture of the sample of comparative example 3 in high temperature and high humidity environment for 240 hours. DETAILED DESCRIPTION

[0066] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0067] Glossary and test methods:

[0068] Glass-ceramics: also known as glass ceramics, is a type of solid composite material that contains both glass phase and crystal phase (microcrystalline phase, crystalline phase) and is prepared by targeted and controlled crystallization of substrate glass.

[0069] Strengthened glass-ceramics: A solid composite material obtained by chemically strengthening glass-ceramics. During high-temperature chemical strengthening, alkali metal ions with large ionic radii (such as potassium and sodium ions) in the salt bath / molten salt replace alkali metal ions with smaller ionic radii (such as sodium and lithium ions) in the glass-ceramics, resulting in a volume difference between the exchanged ions and compressive stress on the glass-ceramics surface.

[0070] Surface CS: surface compressive stress / surface compressive stress. After chemical strengthening of glass-ceramics / glass-ceramics, the alkali metal ions with smaller surface radius are replaced by alkali metal ions with larger radius. Due to the crowding effect of the alkali metal ions with larger radius, compressive stress is generated on the glass surface, which is called surface compressive stress.

[0071] DOL_0: Depth of the compressive stress layer, also known as the depth of the compressive stress layer, refers to the distance from any surface of the glass to the position close to the surface where the compressive stress is zero.

[0072] |CT_AV|: The absolute value of the average tensile stress in the tensile stress layer, specifically the absolute value of the average value of all tensile stresses in the tensile stress layer.

[0073] |CT_CV|: The absolute value of the maximum tensile stress, specifically the absolute value of the maximum tensile stress in the tensile stress layer.

[0074] Glass thickness: Determined by micrometer testing. The change in thickness of glass-ceramics before and after chemical strengthening is very small and can be ignored.

[0075] Definition of surface K2O concentration: Surface K2O concentration equals K2O mass / total oxide mass, where the total oxide mass includes oxides accurately measured by XRF, such as SiO2, Al2O3, P2O5, ZrO2, Na2O, and K2O, and excludes oxides that cannot be accurately measured by XRF, such as Li2O and B2O3. XRF testing uses a standardless method and does not measure the concentration of elements with atomic numbers 6 and below or their oxides in the glass. This means that the total oxide concentration in the calculation of the K2O concentration determined by XRF testing in this disclosure does not include the concentration of elements with atomic numbers 6 and below or their oxides in the glass.

[0076] Refractive index: The ratio of the speed of light in a vacuum to the speed of light in the medium.

[0077] SOC: Photoelastic coefficient. Photoelasticity refers to the anisotropic birefringence of transparent materials when subjected to stress. By measuring the photoelastic coefficient and birefringence, the residual stress (MPa) within the material can be determined.

[0078] Transmittance was tested using a UV2600 visible light spectrophotometer (Shimadzu). In the Examples and Comparative Examples of the present invention, the transmittance of the glass-ceramics at 550 nm was the average transmittance of multiple glass samples from the same batch measured at 550 nm. At least five samples from each batch of glass-ceramics were tested.

[0079] XRD testing method: The crystallized glass-ceramics were ground into a fine glass powder with a particle size of less than 75 μm. The powder was then tested using an X-ray diffractometer (Shimadzu XRD_6000) within a diffraction angle range of 2θ = 10°-50°, a scanning speed of 6° / min, an operating voltage of 40 kV, and an operating current of 30 mA to obtain the XRD diffraction peak curve. The XRD diffraction data was then analyzed using specialized processing software to obtain data such as crystal content / crystalline phase content and average grain size.

[0080] The average grain size was obtained by using the Scherrer formula D = Kλ / (βcosθ) for the XRD test results, where λ is the X-ray wavelength, β is the peak half-height width, and K = 0.89.

[0081] The crystal content / crystalline phase content is determined by testing a glass-ceramic sample using an X-ray diffractometer (Shimadzu XRD-6000). The RAW format of the X-ray diffractometer results is then imported into Rietveld X-ray diffraction data refinement software (such as Gsas, Fullprof, or Maud) for fitting and calculation. The crystal content / crystalline phase content of the glass-ceramic sample is calculated as the ratio of the fitted crystalline phase peak area to the fitted total peak area.

[0082] The differential scanning calorimetry (DSC) test method is as follows: the sample is ground into powder and then passed through a 200-mesh sieve; the test conditions are: room temperature to 1100°C, with a heating rate of 10°C / min; the test instrument is a Mettler-Toledo TGA / DSC3+ thermogravimetric and synchronous thermal analyzer.

[0083] The surface K2O concentration of the strengthened microcrystalline glass of the present invention was measured by X-ray fluorescence spectrometry (XRF). The equipment model used was (Thermo Scientific ARL PERFORM'X), the target material was Rh (rhodium), the light tube voltage was 40KW, the current was 60mA, the collimator was 0.15, the crystal was LiF200, the detector was FPC, the test range was a 29mm circle, and the analysis software was UniQuant standardless analysis. The XRF test used a standardless test and did not test the concentration of elements with atomic numbers 6 and below or their oxides in the glass. That is, when calculating the K2O concentration obtained by the XRF test in the present invention, the total oxide concentration does not include the concentration of elements with atomic numbers 6 and below or their oxides in the glass.

[0084] Surface compressive stress (surface CS) test conditions: using FSM-6000 from Orihara, Japan, light source wavelength of 596 nm, SOC = 25.5 (nm / cm) / MPa, refractive index = 1.54.

[0085] Test conditions for |CT_AV|, DOL_0, and |CT_CV|: Tested using Orihara's SLP-2000, with a light source wavelength of 518 nm, SOC = 25.5 (nm / cm) / MPa, refractive index = 1.54, and exposure time: 300 usec.

[0086] When testing surface CS, |CT_AV|, DOL_0, and |CT_CV|, apply a drop of the corresponding refractive fluid to the corresponding stress gauge. Then, clean the tempered glass-ceramic and place it on the test path to measure the values. The refractive index of the refractive fluid used in the SLP-2000 is 1.51, while that used in the FSM-6000 is 1.72.

[0087] Average sandpaper drop height: The value obtained by dividing the sum of the sandpaper drop heights measured by multiple glass samples by the number of samples tested. It is used to characterize the glass's resistance to contact surface cracking. At least 10 samples are taken from each batch for testing. The average sandpaper drop height is , where n is the number of glass samples tested in each batch, and hi is the sandpaper drop resistance height of a single sample tested.

[0088] Among them, the test method for the sample's resistance to sandpaper drop height is:

[0089] Step 1: Place the glass sample to be tested, which is 158.8mm x 72.8mm x 0.7mm in length, width and thickness, on the front of a 200g model machine.

[0090] Step 2: Place the model phone on a Green Figure LT-SKDL-CD drop machine with the glass sample facing the sandpaper. Drop it from a certain drop height, impacting the 120-grit sandpaper directly below the model phone, to simulate a normal mobile phone drop.

[0091] If the glass sample does not break, the drop height of the model machine is increased in a certain pattern. For example, the drop height starts from 0.4m and the sample is dropped once. If it does not break, the drop height is increased by 0.1m each time until the glass sample breaks.

[0092] Step 3: Record the last drop height of the glass sample when it breaks as the sandpaper drop height. For example, if the drop height when it breaks is 0.5m, the sandpaper drop height of the sample is 0.4m.

[0093] The average single-rod static compressive strength test method is to place the tempered glass-ceramic on the bottom ring of a tensile testing machine (LT_850A), start the test software, set the extrusion rod speed to 50mm / min, click Start Test, and the software will automatically read the force (N) required to break the glass. Ten pieces of glass are tested each time, and the average value is calculated to demonstrate resistance to non-contact cracking.

[0094] The test method for high temperature and high humidity failure time is: use QTH_80C full-one temperature and humidity alternating test chamber for testing, observe and take out the sample every 12 hours, and wipe the glass surface with a dust-free cloth to observe whether there are spots or fog points that cannot be wiped off; the time when spots or fog points that cannot be wiped off appear is the high temperature and high humidity failure time; it is used to characterize weather resistance.

[0095] Specifically, the present invention provides a strengthened glass-ceramic with excellent resistance to non-contact surface cracking, wherein the strengthened glass-ceramic has a compressive stress layer formed by chemical strengthening on the surface, and has a tensile stress layer inside that can achieve force balance with the compressive stress layer, that is, the strengthened glass-ceramic includes a compressive stress layer and a tensile stress layer, and the main crystalline phase of the strengthened glass-ceramic includes a petalite crystal phase and a lithium disilicate crystal phase, and the strengthened glass-ceramic satisfies:

[0096] Surface CS ≥ 400 MPa;

[0097] Surface CS / |CT_AV|≥17.00, |CT_AV| is the absolute value of the average tensile stress in the tensile stress layer, in MPa;

[0098] DOL_0≥0.15t, DOL_0 refers to the depth of the compressive stress layer, and t is the thickness of the strengthened microcrystalline glass.

[0099] The above technical solution of the present invention provides a tempered microcrystalline glass having a specific surface CS and a ratio of surface CS to |CT_AV|, and DOL_0 within the above specific range, so that the tempered microcrystalline glass has a special stress structure. This stress structure enables it to have a sufficient compressive stress level to suppress further expansion of cracks when it is punctured by a sharp object; it also has sufficient stress depth to prevent sudden cracks from penetrating into the tensile stress area and causing breakage; in addition, there is sufficient surface CS to suppress damage to the back side when impacted by a blunt object, thereby ensuring that the tempered microcrystalline glass meets the requirements for resistance to contact surface cracking while also having excellent resistance to non-contact surface cracking.

[0100] In some preferred embodiments of the present invention, in the strengthened glass-ceramics, the total weight of the petalite crystal phase and the lithium disilicate crystal phase accounts for no less than 71.00 wt %.

[0101] In some preferred embodiments of the present invention, the surface K2O concentration of the strengthened glass-ceramics is ≥7.00 wt %. Under this preferred embodiment, the strengthened glass-ceramics can also have excellent weather resistance.

[0102] The present invention also provides a strengthened microcrystalline glass having excellent crack resistance and weather resistance, wherein the strengthened microcrystalline glass has a compressive stress layer formed by chemical strengthening on the surface, and has a tensile stress layer inside that can achieve force balance with the compressive stress layer, the strengthened microcrystalline glass comprising the compressive stress layer and the tensile stress layer, and the strengthened microcrystalline glass comprises a petalite crystal phase and a lithium disilicate crystal phase with a total weight accounting for not less than 71.00wt%; and the strengthened microcrystalline glass satisfies:

[0103] Surface CS ≥ 400 MPa;

[0104] Surface CS / |CT_AV|≥17.00, |CT_AV| is the absolute value of the average tensile stress in the tensile stress layer, in MPa;

[0105] DOL_0≥0.15t, DOL_0 refers to the depth of the compressive stress layer, and t is the thickness of the strengthened glass-ceramic;

[0106] The surface K2O concentration of the strengthened glass-ceramics is ≥7.50 wt%.

[0107] The above technical solution of the present invention provides a strengthened glass-ceramic with a specific surface CS and a ratio of surface CS to |CT_AV|, and DOL_0 within the above specific range, and with a specific and appropriate surface K2O concentration, so that the strengthened glass-ceramic has a special stress structure and composition, and can resist the erosion of water and other components in the air in high temperature and high humidity environments. The inventor believes that the reason may be K + The activity ratio of Na + Low, not easy to react with air and water, and K + Radius larger than Na + , which can block the chemical reaction between other components inside the glass and water and air, thereby ensuring that the strengthened microcrystalline glass meets the requirements of resistance to contact surface cracking while having excellent resistance to non-contact surface cracking and weather resistance.

[0108] In any of the above-mentioned strengthened microcrystalline glasses of the present invention, the inventors have further optimized to improve the comprehensive performance of the strengthened microcrystalline glasses, as follows.

[0109] In order to further optimize the weather resistance of the strengthened microcrystalline glass, preferably, the surface K2O concentration of the strengthened microcrystalline glass is 7.00-15.00wt%, and preferably the surface K2O concentration is 7.50-15.00wt%.

[0110] Preferably, in the strengthened glass-ceramics, the total weight of the petalite crystal phase and the lithium disilicate crystal phase accounts for 71.00-90.00 wt %.

[0111] Preferably, the surface CS of the strengthened glass-ceramics is ≥ 500 MPa, for example, it can be any value among 500 MPa, 550 MPa, 600 MPa, 650 MPa, 700 MPa, 750 MPa, 800 MPa, 850 MPa, 900 MPa, 950 MPa, 1000 MPa, 1200 MPa, and any value between adjacent values. More preferably, the surface CS is 550-1000 MPa, and further preferably 810-900 MPa. In a preferred embodiment of the present invention, when a blunt object contacts the glass-ceramics, its impact force preferentially offsets the surface CS, and due to the high surface CS, the back side (i.e., the non-contact surface) will undergo less deformation, which is more conducive to improving the ability of the strengthened glass-ceramics to resist cracking on the non-contact surface.

[0112] Further preferably, the tempered glass-ceramics has a |CT_AV| ≥ 30 MPa, and can be, for example, any of 30 MPa, 35 MPa, 40 MPa, 45 MPa, 50 MPa, 55 MPa, 60 MPa, 65 MPa, 70 MPa, 75 MPa, and 80 MPa, or any value in between. More preferably, |CT_AV| is between 35 and 60 MPa. In preferred embodiments of the present invention, a higher |CT_AV| can prevent further penetration of sharp objects and lateral crack expansion, thereby further improving the tempered glass-ceramics' resistance to contact surface cracking.

[0113] Further preferably, in the strengthened glass-ceramics, 50.00 ≥ surface CS / |CT_AV| ≥ 17.00, for example, it can be any value among 17, 18, 19, 20, 21, 22, 23, 24, 25, 30, 35, 40, 45, 50, and any value between adjacent values, and is further preferably 18-23. Under this preferred embodiment, the stress structure of the strengthened glass-ceramics is more suitable for improving the resistance to non-contact surface cracking to a higher level.

[0114] More preferably, 0.25t ≥ DOL_0 ≥ 0.15t. For example, DOL_0 can be any of 0.15t, 0.16t, 0.17t, 0.20t, 0.22t, 0.23t, and 0.25t, as well as any value between adjacent values. In this preferred embodiment, the appropriate DOL_0 is compatible with the thickness t, preventing sudden cracks from penetrating the compressive stress region directly into the tensile stress region when a sharp object is inserted, causing shattering. This allows the stress layer of the strengthened glass-ceramic to focus more on resisting contact surface cracking.

[0115] In some preferred embodiments of the present invention, the strengthened glass-ceramics further satisfies the following: |CT_CV| ≥ 50 MPa, where |CT_CV| is the absolute value of the maximum tensile stress in the tensile stress layer. Under this preferred embodiment, the strengthened glass-ceramics exhibits a more optimal tensile stress layer distribution, thereby further enhancing resistance to contact surface cracking.

[0116] More preferably, |CT_CV| is 55-80 MPa.

[0117] More preferably, the ratio of the petalite crystalline phase to the lithium disilicate crystalline phase in the strengthened glass-ceramics is (0.9-1.1):1, preferably 0.90-0.99:1. In this preferred embodiment of the present invention, the main crystalline phases are rationally distributed, thereby further facilitating the full utilization of the strengthened glass-ceramics in terms of resistance to non-contact surface cracking.

[0118] More preferably, the average size of the grains in the strengthened glass-ceramics is ≤100 nm, preferably 10-50 nm, and more preferably 15-25 nm. The present invention has grains of suitable size, which makes the glass more transparent while ensuring strength.

[0119] In some preferred embodiments of the present invention, the composition of the strengthened glass-ceramics tensile stress layer, measured by mass percentage, includes: SiO2: 58.00-76.00%, Al2O3: 6.00-8.00%, P2O5: 2.00-3.00%, ZrO2: 4.00-6.00%, Na2O: 3.00-10.00%, Li2O: 9.00-12.00%, and B2O3: 0-3.00%. In this preferred embodiment, the composition of the strengthened glass-ceramics is more conducive to achieving the aforementioned specific stress distribution, as well as high transparency and intrinsic strength.

[0120] In the composition of the present invention, the role of each element is as follows:

[0121] SiO2, as a former oxide of the glass network, is an indispensable component of the glass network structure. However, excessive SiO2 can increase the viscosity of the glass, causing difficulty in melting the glass. During the crystallization process, SiO2, as an important component of petalite and lithium disilicate, is also indispensable. The inventors have found that when the SiO2 content is controlled within the above-mentioned range, the glass forming and crystallization effects are better. The SiO2 content can be, for example, any value among 58.00, 60.00, 63.00, 65.00, 68.00, 70.00, 72.00, 75.00, 76.00 wt% and any value between adjacent values.

[0122] Al2O3 is a key component of petalite and the primary component controlling the crystalline phase ratio and grain size. Al2O3 also facilitates ion exchange during the strengthening process. However, excessive Al2O3 can also increase the viscosity of the glass. The inventors have discovered that controlling the Al2O3 content within the aforementioned range improves various product properties. The Al2O3 content can be, for example, any of 6.00, 6.50, 7.00, 7.50, and 8.00 wt%, and any value in between.

[0123] P2O5 is an essential component in the present invention as an auxiliary nucleating agent. Excessive or excessive amounts of P2O5 can result in poor crystallization and result in insufficient transparency of the resulting glass-ceramics. Therefore, the P2O5 content is controlled within the aforementioned range. The P2O5 content can be, for example, any of 2.00, 2.20, 2.50, 2.70, 2.90, and 3.00 wt%, or any value between adjacent values.

[0124] ZrO2 serves as the primary nucleating agent in the present invention, reducing grain size. However, excessively high ZrO2 content increases glass melting difficulty and results in the formation of a large amount of white precipitate. Therefore, the ZrO2 content is controlled within the aforementioned range. The ZrO2 content can be, for example, any of 4.00, 4.20, 4.50, 5.00, 5.50, and 6.00 wt%, or any value therebetween.

[0125] Li2O and Na2O, as the external oxides of the glass network, can provide free oxygen, destroy the network structure of the glass, thereby improving the viscosity of the glass, promoting the melting and clarification of the glass liquid, and can also exchange ions with the molten salt bath. The content of both is an important factor affecting the stress of the glass, among which Na2O has a significant effect on the increase of CS on the glass surface. In addition, Li2O is also a lithium silicate (Li2SiO3) and petalite (LiAlSi4O 10 ) and other necessary chemical components for the formation of crystalline phases, however, the addition of excessive Li2O and Na2O may lead to poor stability of the glass crystallization process, a significant decrease in crystallinity / crystal content, and even the precipitation of other crystalline phases. The inventors have found through a large number of experiments that when the Li2O content and the Na2O content are controlled within the above ranges, the various properties of the obtained product can meet the requirements. Among them, the content of Na2O can be, for example, any value among 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 6.50, 7.00, 7.50, 8.00, 9.00, 10.00wt% and any value between adjacent values. Among them, the content of Li2O can be, for example, any value among 9.00, 9.50, 10.00, 10.50, 11.00, 11.50, 12.00wt% and any value between adjacent values.

[0126] In the present invention, B2O3 acts as a flux to reduce the high-temperature viscosity of the glass and alleviate the melting difficulties associated with ZrO2. However, excessive B2O3 can reduce the phase separation of the glass, resulting in decreased transparency. Therefore, the B2O3 content is generally controlled within the above-mentioned range. The B2O3 content can be, for example, any of 0, 0.10, 0.50, 1.00, 1.50, 2.00, 2.50, and 3.00 wt%, and any value therebetween.

[0127] According to the present invention, the average single-rod static compressive strength is used to characterize the resistance to non-contact surface cracking. Preferably, at a thickness of 0.7 mm, the average single-rod static compressive strength of the strengthened glass-ceramic is ≥ 400 N. More preferably, the average single-rod static compressive strength is between 401 and 500 N, for example, any value among 401, 410, 420, 430, 440, 450, 460, 470, 480, 490, and 500 N, or any value in between.

[0128] According to the present invention, weather resistance is characterized by the high-temperature, high-humidity failure time. Preferably, the tempered glass-ceramics are subjected to a high-temperature, high-humidity failure test at 85°C and 85% relative humidity, and the high-temperature, high-humidity failure time is ≥ 204 hours, preferably ≥ 240 hours. The high-temperature, high-humidity failure time is the time it takes for the tempered glass-ceramics to develop indelible spots or fog points under these conditions. The tempered glass-ceramics of the present invention have a long high-temperature, high-humidity failure time and excellent weather resistance.

[0129] According to the present invention, the average sandpaper drop resistance height is used to characterize the resistance to contact surface cracking. Preferably, when the tempered glass-ceramic is subjected to a sandpaper drop resistance test using 120-grit sandpaper at a thickness of 0.7 mm, the average sandpaper drop resistance height is 1.10-1.50 m, for example, any value among 1.1, 1.12, 1.15, 1.18, 1.2, 1.23, 1.25, 1.28, 1.29, 1.3, 1.32, 1.35, 1.38, 1.4, 1.45, 1.5 m, and any value between adjacent values.

[0130] According to the present invention, preferably, at a thickness of 0.7 mm, the transmittance of the strengthened glass-ceramics for light of 550 nm wavelength is not less than 89.00%. The light transmittance of the strengthened glass-ceramics of the present invention is high and can meet market demand.

[0131] The present invention also provides a glass device, wherein the glass device is made of any of the aforementioned strengthened micro-ceramics.

[0132] The glass device of the present invention may be regular or irregular, and those skilled in the art can manufacture it according to requirements.

[0133] The present invention further provides an electronic device, comprising a cover, wherein the cover comprises any of the aforementioned strengthened micro-ceramic glasses.

[0134] The electronic device described in the present invention includes but is not limited to at least one of a mobile phone, a display (such as a car display, an aircraft display, etc.), a tablet computer, an electronic watch, a smart wearable (such as a smart bracelet, a smart watch, smart glasses), and a television.

[0135] In the electronic device of the present invention, a layer may or may not be provided on the surface of the cover.

[0136] In the present invention, those skilled in the art can select the thickness of the strengthened glass-ceramics according to needs. Exemplarily, the thickness of the strengthened glass-ceramics is 0.2-5 mm.

[0137] The present invention has a wide range of optional preparation methods for the strengthened microcrystalline glass described in any of the first and second aspects above. As long as the required conditions such as the above-mentioned stress structure characteristics are met, it can ensure that the strengthened microcrystalline glass has excellent resistance to contact surface cracking and non-contact surface cracking as well as weather resistance.

[0138] Preferably, according to the present invention, a method for preparing the strengthened glass-ceramics is also provided, comprising: preparing substrate glass, nucleation treatment, crystallization treatment, and chemical strengthening treatment.

[0139] In some preferred embodiments, the substrate glass preparation process includes: mixing raw materials, optionally adding a clarifier, melting, forming and cooling, and then annealing and cooling. Preferably, after annealing, the substrate glass is cooled to room temperature to obtain the substrate glass.

[0140] Those skilled in the art can select the conditions for mixing the raw materials according to their needs. Preferably, the mixing time of the raw materials is more than 30 minutes.

[0141] In the present invention, those skilled in the art can select the type (such as NaCl) and dosage of the clarifier according to needs without any creative work.

[0142] Preferably, the melting conditions include: a temperature of 1550-1650° C. and a time of more than 5 hours.

[0143] Preferably, the final cooling temperature of the forming cooling is 700-900°C.

[0144] Preferably, the annealing conditions include: a temperature of 400-500° C. and a time of 12-240 hours.

[0145] In some preferred embodiments, the nucleation treatment conditions include: a nucleation temperature of 500-700°C and a nucleation treatment time of 10-1440 minutes, preferably 50-350 minutes. The nucleation treatment time here refers to the time after heating to the set nucleation temperature at a certain heating rate and then holding the temperature.

[0146] More preferably, the conditions of the nucleation treatment further include: heating to the nucleation temperature at a heating rate of 1-50°C / min, preferably 5-30°C / min.

[0147] In some preferred embodiments, the crystallization treatment conditions include: a crystallization temperature of 600-750°C and a crystallization treatment time of 5-1440 minutes, preferably 50-350 minutes. The crystallization treatment time here refers to the time after heating to the set crystallization temperature at a certain heating rate and then holding the temperature.

[0148] More preferably, the crystallization treatment conditions further include: heating to the crystallization temperature at a heating rate of 1-50° C. / min, preferably 5-30° C. / min.

[0149] In the present invention, after the crystallization treatment, the steps of shaping and polishing are further included, and then the chemical strengthening treatment is performed. Exemplarily, the shaping and polishing steps include: shaping, cutting, and polishing a glass-ceramic sample brick (a glass-ceramic sample brick obtained by subjecting the substrate glass to nucleation and crystallization treatments) to obtain a sample of a fixed size. The sample sizes used in the following embodiments of the present invention include polished pieces with a length, width, and thickness of 50 mm × 50 mm × 0.7 mm and 158.8 mm × 72.8 mm × 0.7 mm.

[0150] In some preferred embodiments, the chemical strengthening treatment process includes: performing a primary strengthening in a sodium-potassium molten salt, and then performing a secondary strengthening in a potassium molten salt.

[0151] More preferably, the conditions for the primary strengthening include: a primary strengthening temperature of 380-550° C., and a primary strengthening time of 1-24 h.

[0152] More preferably, the secondary strengthening conditions include: a secondary strengthening temperature of 400-500° C., and a secondary strengthening time of 5-1440 min.

[0153] More preferably, in the sodium-potassium molten salt, the content of sodium salt is 5-50 wt%, and the content of potassium salt is 50-95 wt%.

[0154] More preferably, the content of potassium salt in the potassium molten salt is 100 wt%.

[0155] More preferably, the sodium salt is selected from at least one of sodium nitrate, sodium sulfate, and sodium carbonate, preferably sodium nitrate; the potassium salt is selected from at least one of potassium nitrate, potassium sulfate, and potassium carbonate, preferably potassium nitrate.

[0156] The present invention can prepare strengthened microcrystalline glass having the aforementioned characteristic stress structure through the above-mentioned strengthening process.

[0157] The present invention will be described in more detail below with reference to specific embodiments.

[0158] Example 1

[0159] Strengthened glass-ceramics is prepared as follows:

[0160] 1. Sample brick melting:

[0161] According to the raw material ratio of the substrate glass (numbered C) in Table 1, 1000 g of raw material was prepared, and then mixed in a V-type mixer for 30 minutes. After mixing, 5 g of a clarifier (NaCl) was added. The raw material was then transferred to a platinum crucible and melted in a 1650°C lifting furnace for 5 hours. The raw material was then poured into a forming mold and cooled to 900°C. The raw material was then placed in a 500°C annealing furnace for annealing for 24 hours, and then cooled to room temperature with the furnace to obtain the substrate glass.

[0162] 2. Sample brick crystallization:

[0163] Transparent microcrystalline glass can be prepared by sequentially subjecting the substrate glass to nucleation treatment and crystallization treatment.

[0164] Specifically, the temperature is first raised to the nucleation temperature at a heating rate of 10°C / min for nucleation treatment; then the temperature is raised to the crystallization temperature at a heating rate of 10°C / min for crystallization treatment. The nucleation temperature, nucleation treatment time, crystallization temperature, and crystallization treatment time are shown in Table 1.

[0165] The crystal content and light transmittance of the transparent microcrystalline glass obtained above were tested. The result data are shown in Table 1. The light transmittance curve is shown in Figure 6 shown.

[0166] 3. Sample processing:

[0167] After shaping, cutting, and polishing, glass-ceramic samples can be obtained into samples of desired dimensions, such as polished glass-ceramic sheets measuring 50 mm x 50 mm x 0.7 mm, 158.8 mm x 72.8 mm x 0.7 mm, etc. The thickness is t = 0.7 mm. The difference between the thickness of glass-ceramic sheets and that of strengthened glass-ceramic sheets obtained through chemical strengthening is very small and can be ignored.

[0168] 4. Chemical strengthening:

[0169] The polished glass-ceramics obtained above were subjected to the first step of strengthening in a sodium-potassium mixed salt bath, where sodium ions were provided by sodium nitrate and potassium ions by potassium nitrate. The glass, after the first step of strengthening, was subjected to the second step of strengthening in a pure potassium salt bath, where potassium salt was provided by potassium nitrate. Thus, strengthened glass-ceramics were obtained.

[0170] The conditions for the first step of strengthening (composition of the first strong salt bath, salt bath temperature and time) and the conditions for the second step of strengthening (composition of the second strong salt bath, salt bath temperature and time) are shown in Table 2 respectively.

[0171] The surface K2O concentration, surface CS, |CT_AV|, |CT_CV|, DOL_0, average sandpaper drop resistance height, average single rod static pressure strength, and high temperature and high humidity failure time of the tempered glass-ceramics obtained above were tested. The results are shown in Table 2. Among them, the glass test picture of surface CS is shown in Table 2. Figure 3 As shown. In the high temperature and high humidity failure time test, the sample picture of high temperature and high humidity environment for 240h is as follows Figure 8 shown.

[0172] In this embodiment, the DSC test curve of the substrate glass and the XRD diffraction test curve of the microcrystalline glass are respectively as follows: Figure 4 、 Figure 5 As shown. Figure 4 It can be seen that this embodiment has clear nucleation and crystallization temperature points, and there are no other impurity phase peaks in the nucleation and crystallization temperature range. Figure 5 It can be seen that the prepared glass-ceramics has good crystallinity and the grain sizes of the two phases are small, which further illustrates its high intrinsic strength and good transparency.

[0173] Example 2-Example 5

[0174] The method of Example 1 was followed, except that the process was carried out according to the formula and process conditions in Table 1 and Table 3. The substrate glasses of Examples 2-5 were numbered D, E, F, and G, respectively.

[0175] The corresponding crystal phase and surface K2O concentration tests and performance tests are shown in Table 1 and Table 3, respectively.

[0176] Example 6

[0177] The method of Example 5 was followed, except that the process conditions in Table 3 were followed and the base glass formula was the same as that of Example 5.

[0178] The corresponding performance tests are shown in Table 3.

[0179] Comparative Example 1-Comparative Example 2

[0180] The method of Example 1 was referred to, except that the substrate glass formulations and process conditions in Tables 1 and 2 (the substrate glasses of Comparative Examples 1-2 were numbered A and B) were used.

[0181] The corresponding crystal phase test and performance test results are shown in Table 1 and Table 2 respectively.

[0182] Comparative Example 3-Comparative Example 5

[0183] The method of Example 1 was used, except that the process conditions in Table 2 were followed, and other conditions such as the base glass formula (base glass numbered C) were the same as those in Example 1.

[0184] The corresponding performance test results are shown in Table 2. Among them, in the high temperature and high humidity failure time test, Figure 7 This is a picture of comparative example 4 after 24 hours in a high temperature and high humidity environment. Figure 9 This is a picture of Comparative Example 3 after 240 hours in a high temperature and high humidity environment.

[0185] Table 1

[0186]

[0187] As can be seen from Table 1, these base glass formulas numbered A, B, C to G can all be processed through certain nucleation and crystallization to obtain microcrystalline glass with high crystallinity and good transmittance. Furthermore, it can be seen from Table 1 that when the Na2O content is greater than 4wt%, the increase in Na2O content will lead to a partial decrease in crystallinity, so that the corresponding product surface CS in Table 2-3 below fluctuates between 800-900MPa, and its average single-rod static pressure strength is slightly reduced. Therefore, the preferred Na2O content of the present invention can ensure that the resulting microcrystalline glass has a higher degree of crystallinity, which is more conducive to the intrinsic strength of the product.

[0188] Table 2

[0189]

[0190] It can be seen from the comparative examples and Example 1 in Table 2 that the solution of the present invention of Example 1, which satisfies the conditions of surface CS ≥ 400 MPa, surface CS / |CT_AV| ≥ 17, and DOL_0 / t ≥ 0.15, has an average anti-sandpaper drop height and an average single-rod static pressure strength at a higher level, indicating that it can obtain better resistance to contact surface cracking and resistance to non-contact surface cracking. However, the comparative examples that only meet one of the above three conditions cannot take into account both resistance to non-contact surface cracking and resistance to contact surface cracking. Furthermore, the present invention also satisfies Example 1 in which the K2O concentration on the sample surface is greater than 7wt%, and its high temperature and high humidity failure time is longer, indicating that it has both excellent resistance to non-contact surface cracking and resistance to contact surface cracking, and better weather resistance.

[0191] Specifically, from Comparative Example 1, Comparative Example 2, and Example 1 in Table 2, it can be seen that the surface K2O concentration of the samples obtained in Comparative Examples 1 and 2 is ≤7wt%, the surface CS is <400 MPa, the surface CS / |CT_AV| is <17, and DOL_0 / t ≥0.15, indicating that Comparative Examples 1 and 2 have good drop heights, but their average single-rod static pressure strength is significantly lower than that of Example 1. In other words, the resistance to contact surface cracking of Comparative Examples 1 and 2 is comparable to that of Example 1, but their resistance to non-contact surface cracking is significantly lower than that of Example 1 of the present invention, which simultaneously meets the requirements of sample surface K2O concentration greater than 7wt%, surface CS ≥400 MPa, surface CS / |CT_AV| ≥17, and DOL_0 / t ≥0.15.

[0192] It can be seen from Comparative Example 3 and Example 1 in Table 2 that although Comparative Example 3 meets the requirements of sample surface K2O concentration ≥ 7wt%, surface CS ≥ 400MPa, and DOL_0 / t ≥ 0.15, due to the long strengthening time, the surface CS drops to 413MPa, resulting in surface CS / |CT_AV| < 17, and its average single-rod static pressure strength decreases, that is, the resistance to non-contact surface cracking is reduced.

[0193] It can be seen from Comparative Example 4 and Example 1 in Table 2 that although Comparative Example 4 uses the same sample as Example 1 for strengthening, since Comparative Example 4 does not undergo secondary strengthening and the strengthening time is insufficient, although the average sandpaper drop resistance height is high, since it does not meet the surface CS / |CT_AV|≥17, its average single-rod static pressure strength is low, that is, the resistance to non-contact surface cracking performance is low.

[0194] It can be seen from Comparative Example 5 and Example 1 in Table 2 that although Comparative Example 5 uses the same sample as Example 1 for strengthening, since Comparative Example 5 does not undergo a single strengthening, although the average single-rod static pressure strength is high, since it does not meet DOL_0 / t≥0.15, its average sandpaper drop resistance height is low, that is, its resistance to contact surface cracking is low.

[0195] Table 3

[0196]

[0197]

[0198] As can be seen from Examples 1, 2, 3, 4, 5, and 6 in Tables 2 and 3, the embodiments of the present invention have an average sandpaper drop resistance of 1.10-1.50 m, an average single-rod static pressure strength of ≥400 N, and a high-temperature and high-humidity failure time of more than 240 h (more than 204 h), indicating that all embodiments of the present invention have excellent resistance to contact surface cracking and non-contact surface cracking, as well as good weather resistance. Figure 7 and Figure 8 By comparison, it can be seen that the weather resistance of the strengthened micro-ceramic glass using the solution of the present invention is significantly better. Figure 9 It can be seen that the weather resistance of comparative example 3 is similar to that of embodiment 1 of the present invention. Figure 8 Similar, but its anti-non-contact surface cracking performance is significantly worse than that of the present invention.

[0199] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A strengthened glass-ceramic, comprising a compressive stress layer and a tensile stress layer, characterized in that: The main crystalline phase of the strengthened glass-ceramics includes a petalite crystalline phase and a lithium disilicate crystalline phase, and the strengthened glass-ceramics satisfies: Surface CS is 500-1000 MPa; 50.00>Surface CS / |CT_AV|≥17.00 and |CT_AV|≥30MPa, where |CT_AV| is the absolute value of the average tensile stress in the tensile stress layer, in MPa; |CT_CV|≥50MPa, |CT_CV| is the absolute value of the maximum tensile stress in the tensile stress layer, in MPa; 0.25t≥DOL_0≥0.15t, DOL_0 refers to the depth of the compressive stress layer, and t is the thickness of the strengthened glass-ceramic; The surface K2O concentration of the strengthened glass-ceramics is 7.00-15.00 wt%.

2. The tempered glass-ceramics according to claim 1, wherein: The surface CS is 550-1000MPa.

3. The tempered glass-ceramics according to claim 1, wherein: |CT_AV| is 35-60MPa.

4. The tempered glass-ceramics according to claim 1, wherein: |CT_CV| is 55-80MPa.

5. The tempered glass-ceramics according to any one of claims 1 to 4, characterized in that: In the strengthened glass-ceramics, the total weight of the petalite crystal phase and the lithium disilicate crystal phase accounts for no less than 71.00 wt %.

6. The tempered glass-ceramics according to claim 5, wherein: In the strengthened glass-ceramics, the total weight of the petalite crystal phase and the lithium disilicate crystal phase accounts for 71.00-90.00 wt %.

7. The tempered glass-ceramics according to claim 6, wherein: In the strengthened glass-ceramics, the weight ratio of the petalite crystal phase to the lithium disilicate crystal phase is (0.9-1.1):

1.

8. The tempered glass-ceramics according to claim 7, wherein: In the strengthened glass-ceramics, the average size of the grains is ≤100 nm.

9. The tempered glass-ceramics according to claim 8, wherein: In the strengthened glass-ceramics, the average size of the grains is 10-50 nm.

10. The tempered glass-ceramics according to claim 9, wherein: In the strengthened glass-ceramics, the average size of the grains is 15-25 nm.

11. The tempered glass-ceramics according to claim 8, wherein In terms of mass percentage, the composition of the strengthened microcrystalline glass tensile stress layer includes: SiO2: 58.00-76.00%, Al2O3: 6.00-8.00%, P2O5: 2.00-3.00%, ZrO2: 4.00-6.00%, Na2O: 3.00-10.00%, Li2O: 9.00-12.00%, and B2O3: 0-3.00%.

12. The tempered glass-ceramics according to any one of claims 1 to 4, characterized in that: At a thickness of 0.7 mm, the average single-rod static compressive strength of the strengthened microcrystalline glass is ≥400N.

13. The tempered glass-ceramics according to claim 12, wherein: At a thickness of 0.7 mm, the average single-rod static compressive strength of the strengthened glass-ceramics is 401-500N.

14. The strengthened glass-ceramics according to any one of claims 1 to 4, characterized in that: Under the conditions of 85°C and 85% relative humidity, the tempered microcrystalline glass is subjected to a high temperature and high humidity failure test, and its high temperature and high humidity failure time is more than 240 hours. The high temperature and high humidity failure time is the time when spots or fog points that cannot be wiped off appear on the tempered microcrystalline glass under the corresponding high temperature and high humidity conditions.

15. The tempered glass-ceramics according to any one of claims 1 to 4, characterized in that: At a thickness of 0.7 mm, the tempered glass-ceramic was subjected to a sandpaper drop resistance test using 120-grit sandpaper, and the average sandpaper drop resistance height was 1.10-1.50 m.

16. The strengthened glass-ceramics according to any one of claims 1 to 4, characterized in that: At a thickness of 0.7 mm, the transmittance of the strengthened microcrystalline glass is not less than 89.00% for light with a wavelength of 550 nm.

17. A strengthened glass-ceramic, comprising a compressive stress layer and a tensile stress layer, characterized in that: The strengthened glass-ceramics comprises a petalite crystal phase and a lithium disilicate crystal phase accounting for no less than 71.00 wt% of the total weight; The strengthened glass-ceramics meets the following requirements: Surface CS is 500-1000 MPa; 50.00>Surface CS / |CT_AV|≥17.00 and |CT_AV|≥30MPa, where |CT_AV| is the absolute value of the average tensile stress in the tensile stress layer, in MPa; |CT_CV|≥50MPa, |CT_CV| is the absolute value of the maximum tensile stress in the tensile stress layer, in MPa; 0.25t≥DOL_0≥0.15t, DOL_0 refers to the depth of the compressive stress layer, and t is the thickness of the strengthened glass-ceramic; The surface K2O concentration of the strengthened glass-ceramics is 7.5-15.00wt%; The thickness of the strengthened glass-ceramics is 0.2-5 mm.

18. The tempered glass-ceramics according to claim 17, wherein: The surface CS is 550-1000MPa.

19. The strengthened glass-ceramics according to claim 17, wherein: |CT_AV| is 35-60MPa.

20. The strengthened glass-ceramics according to claim 17, wherein: |CT_CV| is 55-80MPa.

21. The strengthened glass-ceramics according to any one of claims 17 to 20, characterized in that: In the strengthened glass-ceramics, the total weight of the petalite crystal phase and the lithium disilicate crystal phase accounts for 71.00-90.00 wt %.

22. The strengthened glass-ceramics according to claim 21, wherein: In the strengthened glass-ceramics, the weight ratio of the petalite crystal phase to the lithium disilicate crystal phase is (0.9-1.1):

1.

23. The strengthened glass-ceramics according to claim 22, wherein: In the strengthened glass-ceramics, the average size of the grains is ≤100 nm.

24. The strengthened glass-ceramics according to claim 23, wherein: In the strengthened glass-ceramics, the average size of the grains is 10-50 nm.

25. The strengthened glass-ceramics according to claim 24, wherein: In the strengthened glass-ceramics, the average size of the grains is 15-25 nm.

26. The strengthened glass-ceramics according to claim 23, wherein: In terms of mass percentage, the composition of the strengthened microcrystalline glass tensile stress layer includes: SiO2: 58.00-76.00%, Al2O3: 6.00-8.00%, P2O5: 2.00-3.00%, ZrO2: 4.00-6.00%, Na2O: 3.00-10.00%, Li2O: 9.00-12.00%, and B2O3: 0-3.00%.

27. The strengthened glass-ceramics according to any one of claims 17 to 20, characterized in that: At a thickness of 0.7 mm, the average single-rod static compressive strength of the strengthened microcrystalline glass is ≥400N.

28. The strengthened glass-ceramics according to claim 27, wherein: At a thickness of 0.7 mm, the average single-rod static compressive strength of the strengthened glass-ceramics is 401-500N.

29. The strengthened glass-ceramics according to any one of claims 17 to 20, characterized in that: Under the conditions of 85°C and 85% relative humidity, the tempered microcrystalline glass is subjected to a high temperature and high humidity failure test, and its high temperature and high humidity failure time is more than 240 hours. The high temperature and high humidity failure time is the time when spots or fog points that cannot be wiped off appear on the tempered microcrystalline glass under the corresponding high temperature and high humidity conditions.

30. The strengthened glass-ceramics according to any one of claims 17 to 20, characterized in that: At a thickness of 0.7 mm, the tempered glass-ceramic was subjected to a sandpaper drop resistance test using 120-grit sandpaper, and the average sandpaper drop resistance height was 1.10-1.50 m.

31. The strengthened glass-ceramics according to any one of claims 17 to 20, characterized in that: At a thickness of 0.7 mm, the transmittance of the strengthened microcrystalline glass is not less than 89.00% for light with a wavelength of 550 nm.

32. A glass device, characterized in that: The glass device is made of the strengthened micro-ceramic glass according to any one of claims 1 to 16 or claims 17 to 31.

33. An electronic device comprising a cover, characterized in that: The cover comprises the strengthened glass-ceramic according to any one of claims 1 to 16 or claims 17 to 31.

34. The electronic device according to claim 33, wherein: The electronic device includes at least one of a mobile phone, a display, a tablet computer, a smart wearable device, and a television.

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