High-strength impact-resistant tempered glass and preparation method thereof

Abstract

The invention discloses high-strength impact-resistant tempered glass and a preparation method thereof, and belongs to the technical field of inorganic non-metallic materials. A rare earth doped Al2O3-ZrO2 nano-composite precipitated phase is uniformly dispersed and distributed in a tempered glass matrix, and the rare earth doped Al2O3-ZrO2 nano-composite precipitated phase is composed of Y3 + or Ce4 + stabilized tetragonal phase ZrO2 and spinel type Al2ZrO5; the glass has a gradient stress structure, and comprises an upper surface compressive stress layer, a lower surface compressive stress layer and a subsurface toughness buffer area positioned below the upper surface compressive stress layer and the lower surface compressive stress layer, and the buffer area is in a micro-tensile stress state and contains the nano-composite precipitated phase. Through the collaborative design of rare earth doped nano phase change toughening and asymmetric gradient stress, the mechanical property of hard surface and tough interior is achieved, the impact resistance height is high, the fracture toughness is large, the structural integrity is still kept after multi-point impact, and the composite material is particularly suitable for high-safety-requirement scenes such as building curtain walls, explosion-proof windows and new energy automobile skyscreens.

Description

Technical Field

[0001] This invention belongs to the field of inorganic non-metallic materials technology, specifically relating to a high-strength impact-resistant tempered glass and its preparation method. Background Technology

[0002] Tempered glass, due to its high surface compressive stress, possesses 3-5 times higher mechanical strength and thermal stability than ordinary annealed glass, and is widely used in modern industrial and civilian fields. However, traditional physically tempered glass still has significant shortcomings when facing high-speed projectiles, explosive shock waves, or multiple localized impacts. Although existing tempering processes can form a compressive stress layer on the surface, this layer is relatively shallow and has limited effectiveness in suppressing the propagation of deep cracks. Once the surface compressive stress layer is penetrated, the internal tensile stress zone rapidly releases energy, causing the entire glass to shatter in a "spider web" pattern, significantly reducing its overall load-bearing capacity. Chemical tempering can achieve a deeper compressive stress layer, but its processing cycle is longer, its cost is higher, and its application in large-size flat glass is limited. Furthermore, regardless of whether it is physically or chemically tempered, its internal structure is a homogeneous glass matrix, lacking an effective energy dissipation mechanism. Under multi-point impact conditions, it is prone to cumulative damage, which may lead to sudden failure.

[0003] Patent application CN114133138A discloses a high-strength explosion-proof tempered glass and its manufacturing process. This patent improves the impact and bending strength of the glass by introducing various inorganic reinforcing fibers, such as high-strength silicon-aluminum-magnesium fibers, silicon nitride fibers, and alumina fibers, into the glass raw materials. However, this technical solution relies on the uniform dispersion of fibers during the high-temperature melting process. In actual production, the fibers are prone to agglomeration or sedimentation, leading to uneven mechanical properties. Furthermore, the addition of multiple high-melting-point fibers significantly increases the melting temperature and energy consumption, which is detrimental to continuous industrial production and may affect the glass's light transmittance and optical uniformity.

[0004] Existing technologies for improving the multi-point impact resistance of tempered glass either rely on the introduction of complex components, which increases the difficulty of the process, or employ multi-layer composite structures that sacrifice lightweight and intrinsic properties. These technologies struggle to simultaneously achieve high surface hardness, subsurface toughness, and directional control of stress distribution. Therefore, this invention aims to provide a high-strength impact-resistant tempered glass and its preparation method, which significantly improves the overall resistance to damage and service safety of the glass under complex impact conditions while maintaining good optical properties. Summary of the Invention

[0005] One of the objectives of this invention is to provide a high-strength, impact-resistant tempered glass that solves the problem in the prior art where tempered glass shatters completely and its load-bearing capacity drops sharply when faced with high-speed flying objects, explosive shock waves, or multi-point localized impacts.

[0006] The second objective of this invention is to provide a method for preparing high-strength impact-resistant tempered glass, which is used to prepare the aforementioned high-strength impact-resistant tempered glass.

[0007] The objective of this invention can be achieved through the following technical solutions: In a first aspect, a high-strength, impact-resistant tempered glass is provided, wherein a rare-earth-doped Al2O3-ZrO2 nanocomposite precipitate is uniformly dispersed in the glass matrix, and the precipitate is composed of Y... 3+ or Ce 4+ The glass is composed of stabilized tetragonal ZrO2 and spinel-type Al2ZrO5 with a particle size in the nanometer range. The glass has a gradient stress structure, including an upper surface compressive stress layer, a lower surface compressive stress layer, and a subsurface toughness buffer layer located inside the upper surface compressive stress layer and the lower surface compressive stress layer, respectively. The subsurface toughness buffer layer contains the nanocomposite precipitates and is in a state of micro-tensile stress.

[0008] By introducing rare-earth-doped Al2O3-ZrO2 nanocomposite precipitates into a glass matrix and combining them with an asymmetric air-cooling process, a gradient mechanical structure with a "hard surface and tough interior" is constructed in the thickness direction of the glass. 3+ or Ce 4+ Ions can dissolve into the ZrO2 lattice, suppressing its spontaneous transformation from tetragonal to monoclinic phase at service temperatures, thus maintaining t-ZrO2 in a metastable state at room temperature. When the crack propagates to the subsurface layer, the stress field triggers the t→m phase transformation, accompanied by volume expansion, generating reverse compressive stress at the crack tip, hindering further crack propagation. Simultaneously, asymmetric cooling creates differentiated compressive stress layers on the upper and lower surfaces, matching the unilateral impact conditions commonly encountered in practical applications. The micro-tensile stress zone in the subsurface layer, in synergy with the nano-precipitated phases, forms local energy dissipation units, converting impact kinetic energy into phase transformation work and plastic deformation energy, preventing energy concentration in a single crack path.

[0009] Furthermore, the particle size of the nanocomposite precipitates is 20–80 nm; the compressive stress of the upper surface compressive stress layer is ≥120 MPa, and the compressive stress of the lower surface compressive stress layer is ≥100 MPa; the depth of the subsurface toughness buffer layer is 30–100 μm, and the stress value under micro-tensile stress is +5 to +15 MPa. The particle size is controlled at 20–80 nm because if it is too small, it is difficult to form an effective phase transformation toughening effect, while if it is too large, stress concentration is likely to occur at the particle-matrix interface; the differentiated design of the upper and lower surface compressive stresses is to match the stress characteristics of the upper surface bearing the main impact under unilateral impact conditions; the buffer depth and micro-tensile stress range are to ensure that the stress field can accurately trigger the phase transformation of the precipitates, while avoiding excessive tensile stress that could lead to spontaneous cracking of the glass.

[0010] Furthermore, the glass matrix composition is 68–72 wt% SiO2, 10–14 wt% Al2O3, 8–12 wt% Na2O, 5–7 wt% CaO, and 1–3 wt% MgO, with the balance being unavoidable impurities. This composition system exhibits good melt flowability and precipitate compatibility. The increased Al2O3 content facilitates the formation of the Al2ZrO5 spinel phase, enhancing the interfacial bonding strength.

[0011] Furthermore, the rare earth-doped Al2O3-ZrO2 nanocomposite particles are prepared using a coprecipitation-sol-gel coupling method, specifically including the following steps: B1. Prepare a mixed aqueous solution with a total metal ion concentration of 1.1-1.3 mol / L by mixing aluminum nitrate, zirconium oxychloride and rare earth nitrates in a molar ratio of Al:Zr:RE=3:1:(0.05–0.15); The Al:Zr ratio of 3:1 is used to match the stoichiometric ratio of the subsequent Al2ZrO5 spinel phase, ensuring that Al and Zr elements react fully. The RE molar ratio of 0.05–0.15 can effectively stabilize the tetragonal ZrO2 phase, avoiding excessive doping that could lead to lattice distortion or the precipitation of a second phase, affecting transmittance and thermal stability. The total metal ion concentration is controlled at 1.1–1.3 mol / L. Too low a concentration will result in less precipitation and lower efficiency, while too high a concentration can easily cause excessively high local ion concentrations, affecting the uniformity of precipitation.

[0012] B2. Under the conditions of 48-52°C water bath and 700-900rpm stirring, add 25% ammonia water dropwise at a rate of 3mL / min until the pH=8.7-8.9, continue stirring for 1-2h and then let it stand for aging for 12-16h. pH=8.7-8.9 is Al 3+ Zr 4+ RE 3+ / RE 4+ The optimal range for complete sedimentation; subsequent stirring and aging are to ensure complete crystallization of the precipitate and improve particle uniformity; B3. Centrifuge to separate the precipitate, wash with water until the conductivity is <50μS / cm, and then wash twice with anhydrous ethanol; Washing with water until the conductivity is <50μS / cm is to thoroughly remove impurity ions such as nitrate and chloride ions from the precipitate, so as to avoid the residual impurities affecting the subsequent powder properties. B4. Disperse the washed precipitate in anhydrous ethanol, add citric acid in a molar amount that is 1.1-1.3 times the total molar amount of metal ions, and stir at 58-62°C for 2-3 hours to form a transparent sol. Citric acid, as a complexing agent, at a molar amount of 1.1-1.3 times, can ensure complete complexation of metal ions and prevent particle coarsening during subsequent calcination. Stirring at 58-62°C can promote the full progress of the complexation reaction, forming a stable transparent sol, which lays the foundation for the subsequent preparation of uniform powder.

[0013] B5. The sol was dried at 80°C for 12 hours to obtain a dry gel, which was then calcined in a muffle furnace with a programmed temperature increase: the temperature was increased to 300°C at 2-3°C / min and held for 1 hour, and then increased to 600–650°C at 1.5-2°C / min and held for 2 hours. After natural cooling, it was ground through a 200-mesh sieve to obtain rare earth-doped Al2O3-ZrO2 nanocomposite particles.

[0014] Furthermore, the rare earth nitrate mentioned in step B1 is yttrium nitrate [Y(NO3)3·6H2O] or cerium nitrate [Ce(NO3)3·6H2O]. It has good solubility in aqueous solution and can rapidly dissociate from Y. 3+ Ce 3+ Furthermore, the decomposition products of nitrates are gases, which do not leave impurities in the powder, thus avoiding affecting the purity of the nanocomposite particles and the subsequent glass properties.

[0015] Furthermore, in step B5, the calcination temperature is strictly controlled at 600–650°C. If the temperature is below 600°C, the organic residues are not completely decomposed, and if the temperature is above 650°C, the grains grow to >100nm, thus losing the nano-effect.

[0016] Secondly, a method for preparing high-strength impact-resistant tempered glass includes the following steps: C1. Mix the glass matrix batch with an appropriate amount of rare earth-doped Al2O3-ZrO2 nanocomposite particles, melt them in a molten pool at a suitable temperature for a suitable time, and during the process, introduce nitrogen gas for protection and stir for a suitable time. C2. Molten glass is formed into flat glass of a specific thickness by float glass process and then sent to an annealing furnace for annealing; C3. The formed glass is subjected to heating, heat preservation, slow cooling and natural cooling steps to complete the first stage of low temperature annealing; C4. After the annealed glass is heated and kept warm in the tempering furnace, it enters the asymmetric air grid system for cooling. After cooling to below the set temperature, it is taken out of the furnace to obtain high-strength impact-resistant tempered glass.

[0017] During the melt doping stage, nanoparticles partially dissolve in the glass melt and selectively precipitate in the subsurface region during cooling, forming a uniformly dispersed nanocomposite phase. The first-stage annealing is carried out above the glass transition temperature, promoting the precipitation of ZrO2 in a tetragonal phase and its reaction with Al2O3 to form the Al2ZrO5 interfacial phase, enhancing its bonding with the matrix. In the asymmetric air-cooling stage, the upper surface cools faster than the lower surface, resulting in asymmetric compressive stresses on both surfaces and the formation of a micro-tensile stress zone in the subsurface. This zone coincides with the distribution of the nanoprecipitated phases, constituting a stress-phase transformation synergistic toughening unit.

[0018] Furthermore, in step C1, the amount of rare earth-doped Al2O3-ZrO2 nanocomposite particles added is 0.5–2.0 wt%, preferably 1.0 wt%; the melting temperature is 1500–1600°C, the melting time is 60–65 min, the stirring rate is 30–40 rpm, and the stirring time is 40–50 min. 0.5 wt% of particles is the minimum amount required for effective toughening; an excess of 2.0 wt% can easily lead to agglomeration and a decrease in light transmittance. The melting temperature ensures that the glass batch is fully melted and the particles are partially dissolved.

[0019] Furthermore, in step C2, the thickness of the float-formed flat glass is 3–6 mm, and the inlet temperature of the annealing furnace is 570–590°C. The inlet temperature of the annealing furnace is close to the glass transition temperature, which can alleviate the internal stress generated during the float forming process and lay the foundation for subsequent low-temperature annealing and tempering.

[0020] Furthermore, in step C3, the specific parameters for the first stage of low-temperature annealing are as follows: heating to 570-590°C at a heating rate of 3-4°C / min, holding at that temperature for 45-50 min, then slowly cooling to 390-410°C at a rate of 1-2°C / min, and then naturally cooling to room temperature; wherein the glass transition temperature Tg≈560°C.

[0021] Furthermore, in step C4, the heating temperature of the tempering furnace is 690-710°C, and the holding time is 5-8 minutes; the air pressure on the upper surface of the asymmetric air grid system is 130-140 kPa, the air pressure on the lower surface is 90-100 kPa, the cooling rate ratio is (1.3-1.4):1, and the furnace is removed after cooling to below 75-80°C.

[0022] Furthermore, the asymmetric air grating system includes an upper air grating and a lower air grating. The upper air grating has a nozzle orifice diameter of 0.8 mm, a spacing of 12 mm, and an air pressure adjustment range of 120–150 kPa; the lower air grating has a nozzle orifice diameter of 1.0 mm, a spacing of 15 mm, and an air pressure adjustment range of 80–100 kPa. The upper and lower air gratings start synchronously, with the cooling time controlled within 120–150 seconds. The combination of nozzle parameters and air pressure ensures a stable and controllable difference in cooling rates between the upper and lower surfaces, forming the gradient stress distribution required by the design.

[0023] Furthermore, the formation mechanism of the gradient stress structure is as follows: asymmetric cooling causes the upper surface to contract rapidly and be under pressure, while the lower surface cools more slowly, resulting in lower compressive stress; the central layer generates tensile stress due to volume conservation; and in the depth range of 30–100 μm, the cooling rate is between that of the surface and the center, and is affected by the difference in the thermal expansion coefficients of the nano-precipitated phases, forming a micro-tensile stress state. In this region, t-ZrO2 undergoes a stress-induced phase transition under impact load, and its volume expansion offsets part of the tensile stress while absorbing impact energy, achieving a multi-level protection mechanism of "hard surface layer resisting penetration, tough secondary layer absorbing energy, and central layer protecting the overall structure."

[0024] The beneficial effects of this invention are: (1) The high-strength impact-resistant tempered glass provided by this invention achieves significantly better comprehensive performance than traditional tempered glass through the synergistic effect of its core technical features. The rare earth-doped Al2O3-ZrO2 nanocomposite precipitates endow the glass with excellent phase transformation toughening properties. 3+ or Ce 4+ The stabilized tetragonal ZrO2 remains metastable at room temperature. When the crack extends to the subsurface, the stress field can trigger its transformation into a monoclinic phase, accompanied by volume expansion, forming a reverse compressive stress at the crack tip to hinder crack propagation. Meanwhile, spinel-type Al2ZrO5 has good compatibility with the glass matrix, which can strengthen the interfacial bonding between the precipitated phase and the matrix, avoid interfacial stress concentration, and maximize the coverage of the toughening effect with the uniform dispersion of nano-sized particles.

[0025] (2) The gradient stress structure in the high-strength impact-resistant tempered glass provided by the present invention is precisely adapted to the actual service conditions. The upper and lower surface compressive stress layers directly improve the hardness and penetration resistance of the glass surface. The differentiated compressive stress design can be specifically matched to common usage scenarios where single-sided impact is the main factor, so that the upper surface, which is mainly subjected to force, has a higher impact resistance threshold. The secondary surface toughness buffer contains nanocomposite precipitates and is in a micro-tensile stress state, which not only provides the necessary stress conditions for stress-induced phase transformation, but also works with the precipitates to form a local energy dissipation unit, which efficiently converts the impact kinetic energy into phase transformation work and plastic deformation energy, effectively avoiding sudden fracture caused by energy concentration in a single crack path.

[0026] (3) The phase transformation toughening of the rare earth-doped Al2O3-ZrO2 nanocomposite precipitates and the stress regulation of the gradient stress structure used in this invention form a complementary and synergistic effect, constructing an optimized performance system that is "hard on the surface and tough on the inside". This system not only resists the initial impact and scratches through the compressive stress of the surface layer, but also inhibits crack propagation through the "phase transformation-energy dissipation" mechanism of the subsurface layer, while ensuring the integrity of the glass core layer structure. Ultimately, the glass achieves high strength, high toughness and excellent impact resistance, breaking through the performance bottleneck of traditional tempered glass that is "hard and brittle", and significantly expanding its application prospects in fields with high safety protection requirements such as construction and transportation. Detailed Implementation

[0027] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0028] Example 1

[0029] This embodiment provides a high-strength, impact-resistant tempered glass, which is prepared through the following steps: S1. Preparation of rare earth-doped Al2O3-ZrO2 nanocomposite particles: B1. Accurately weigh 28.6 g (0.075 mol) of aluminum nitrate [Al(NO3)3·9H2O], 9.0 g (0.025 mol) of zirconium oxychloride [ZrOCl2·8H2O], and 0.82 g (0.0025 mol) of yttrium nitrate [Y(NO3)3·6H2O], and prepare a mixed aqueous solution with a total metal ion concentration of 1.2 mol / L and a total volume of 625 mL according to the molar ratio of Al:Zr:Y=3:1:0.1. B2. Place the mixed solution in a constant temperature water bath, control the water bath temperature at 50°C, stir continuously at 800 rpm, add 25% ammonia water dropwise at a rate of 3 mL / min, stop adding when the pH meter shows pH=8.8, continue stirring for 1.5 h, and then let it stand for 14 h to age. B3. Transfer the aged precipitate to a centrifuge tube, centrifuge at 8000 rpm for 10 min, discard the supernatant, wash the precipitate repeatedly with deionized water until the conductivity is <50 μS / cm, and then wash twice with anhydrous ethanol. B4. Disperse the washed precipitate in 200 mL of anhydrous ethanol, add 1.45 g of citric acid (total molar amount of Al+Zr+Y × 1.2), place in a 60°C water bath, and stir at 300 rpm for 2.5 h to form a uniform and transparent sol. B5. Transfer the sol to a petri dish and dry it in an 80°C oven for 12 hours to obtain a dry gel. Then, transfer the dry gel to a muffle furnace for programmed calcination: increase the temperature to 300°C at 2°C / min and hold for 1 hour, then increase it to 620°C at 1.5°C / min and hold for 2 hours. After natural cooling, grind it through a 200-mesh sieve to obtain Y. 3+ Nanocomposite particles doped with Al2O3-ZrO2.

[0030] S2. Melt doping: 200 kg of glass matrix batch (70 wt% SiO2, 12 wt% Al2O3, 10 wt% Na2O, 6 wt% CaO, 2 wt% MgO) is added to an electric melting furnace and melted at 1550°C for 1 hour. After the glass melt is clear, 2.0 kg (1.0 wt%) of the above-mentioned nanocomposite particles are added and stirred continuously at 35 rpm for 45 min to ensure that the nanoparticles are uniformly dispersed in the glass melt.

[0031] S3. Forming: Molten glass is formed into 5mm thick flat glass using the float glass process. The inlet temperature of the annealing furnace is controlled at 580°C, and the glass enters the annealing furnace for preliminary annealing.

[0032] S4. First-stage low-temperature annealing: The float-formed glass is heated to 580°C (slightly above the glass transition temperature Tg≈560°C) at a heating rate of 3.5°C / min, held at that temperature for 48 min, then slowly cooled to 400°C at a rate of 1.5°C / min, and finally allowed to cool naturally to room temperature. This stage promotes the selective precipitation of ZrO2 in the tetragonal phase in the subsurface region, and its reaction with Al2O3 to form the Al2ZrO5 interface phase.

[0033] S5. Second Stage Asymmetric Air-Cooled Tempering: The annealed glass is placed in a tempering furnace and heated to 700°C for 6 minutes, then transferred to an asymmetric air grid system. The upper air grid nozzles have a diameter of 0.8 mm, a spacing of 12 mm, and an air pressure of 135 kPa; the lower air grid nozzles have a diameter of 1.0 mm, a spacing of 15 mm, and an air pressure of 95 kPa. The upper and lower air grids are activated simultaneously, and after 135 seconds of cooling, the glass is cooled to below 78°C, resulting in high-strength, impact-resistant tempered glass.

[0034] Example 2

[0035] The difference between this embodiment and Embodiment 1 is that in step S1, yttrium nitrate is replaced with cerium nitrate. 3+ During calcination, it is partially oxidized to Ce. 4+The process achieves t-ZrO2 stabilization; in step S2, the amount of nanocomposite particles incorporated is 1.2 wt%; in step S4, the annealing temperature is 600°C; and in step S5, the tempering temperature is 710°C. The remaining raw materials and preparation process are the same as in Example 1.

[0036] Example 3

[0037] The difference between this embodiment and Example 1 is that in step S1, the concentration of the yttrium nitrate solution is adjusted to 0.0165 mol / L (Y). 3+ (5% of the molar amount of Zr), the remaining raw materials and preparation process are the same as in Example 1.

[0038] Example 4

[0039] The difference between this embodiment and Example 1 is that in step S1, the concentration of the yttrium nitrate solution is adjusted to 0.0495 mol / L (Y). 3+ (15% of the molar amount of Zr), the remaining raw materials and preparation process are the same as in Example 1.

[0040] Example 5

[0041] The difference between this embodiment and Example 1 is that in step S1, the calcination temperature is adjusted to 600°C, and the average particle size of the obtained nanoparticles is 20 nm. The other raw materials and preparation process are the same as in Example 1.

[0042] Example 6

[0043] The difference between this embodiment and Example 1 is that in step S1, the calcination temperature is adjusted to 650°C, and the average particle size of the obtained nanoparticles is 80 nm. The other raw materials and preparation process are the same as in Example 1.

[0044] Example 7

[0045] The difference between this embodiment and embodiment 1 is that in step S5, the wind pressure on the upper surface is adjusted to 120 kPa, the wind pressure on the lower surface is adjusted to 100 kPa, the cooling rate ratio is 1.2:1, and the remaining raw materials and preparation process are the same as in embodiment 1.

[0046] Example 8

[0047] The difference between this embodiment and embodiment 1 is that in step S5, the wind pressure on the upper surface is adjusted to 150 kPa, the wind pressure on the lower surface is adjusted to 83.3 kPa, the cooling rate ratio is 1.8:1, and the remaining raw materials and preparation process are the same as in embodiment 1.

[0048] Comparative Example 1

[0049] The difference between this comparative example and Example 1 is that: in step S1, no rare earth nitrates were added, and only Al2O3-ZrO2 nanoparticles were prepared; the remaining raw materials and preparation process remained the same as in Example 1.

[0050] Comparative Example 2

[0051] The difference between this comparative example and Example 1 is that no nanoparticles were added, while the other raw materials and preparation process remained the same as in Example 1.

[0052] Comparative Example 3

[0053] The difference between this comparative example and Example 1 is that in step S5, the wind pressure on both the upper and lower surfaces is 110 kPa, and a symmetrical air-cooling process is used. The remaining raw materials and preparation process are the same as in Example 1.

[0054] Comparative Example 4

[0055] The difference between this comparative example and Example 1 is that step S4 (first-stage low-temperature annealing) is omitted, while the remaining raw materials and preparation process are the same as in Example 1.

[0056] Comparative Example 5

[0057] The difference between this comparative example and Example 1 is that in step S1, the calcination temperature was adjusted to 680°C, and the average particle size of the obtained nanoparticles was 110 nm. The other raw materials and preparation process remained the same as in Example 1.

[0058] Comparative Example 6

[0059] The difference between this comparative example and Example 1 is that in step S1, the concentration of the yttrium nitrate solution was adjusted to 0.066 mol / L (Y). 3+ (20% of the molar amount of Zr), the remaining raw materials and preparation process are the same as in Example 1.

[0060] Performance testing

[0061] All tempered glass samples prepared in the examples and comparative examples were subjected to the following performance tests after 72 hours of curing: 1. Impact resistance test: Referring to GB 15763.2-2005 "Safety glass for building - Part 2: Tempered glass", a 1040 g steel ball was dropped freely from different heights to impact the center of the glass, and the critical height at which the glass broke was recorded.

[0062] 2. Fracture toughness test: The fracture toughness K_IC was tested using the single-sided notched beam method (SENB) according to ASTM C1421-19.

[0063] 3. Stress distribution test: The surface compressive stress was measured using an FSM-6000LE surface stress meter, and the stress state in the subsurface layer within a depth range of 30–100 μm was measured using X-ray diffraction.

[0064] 4. Multi-point impact test: Five impact tests at the same height were performed at different locations on the glass surface, and the crack propagation and final breakage state were recorded after each impact.

[0065] 5. Light transmittance test: Refer to GB / T 2680-2021 "Determination of visible light transmittance, direct solar transmittance, total solar transmittance, ultraviolet transmittance and related window glass parameters of architectural glass" to test the visible light transmittance.

[0066] The test results are shown in Table 1: Table 1

[0067] As shown in Table 1, the impact resistance height of all embodiments (1-8) is significantly higher than that of the comparative example, indicating the effectiveness of the technical solution of the present invention. Embodiment 1 exhibits the best overall performance, with an impact resistance height of 2.30 m, which is 53% higher than that of ordinary tempered glass (comparative example 2), and a fracture toughness K_IC of 1.92 MPa·m. 1 / 2 It is 2.02 times that of ordinary tempered glass.

[0068] Regarding the rare earth doping amount, the performance of Examples 3 (5%) and 4 (15%) was slightly lower than that of Example 1 (10%), indicating that there is an optimal range for rare earth doping amount. The subsurface stress state (+6.2 MPa) of Example 3 was close to the lower limit of micro-tensile stress, indicating insufficient phase transformation toughening effect; although the subsurface stress state (+9.1 MPa) of Example 4 was within the ideal range, the excessive rare earth caused some lattice distortion, affecting the phase transformation driving force.

[0069] The effect of nanoparticle size on performance was demonstrated in Examples 5 (20 nm) and 6 (80 nm). The particles in Example 5 were too small, resulting in insufficient phase transformation driving force; the particles in Example 6 were close to the upper limit, but still within the effective range, and the performance was comparable to that of Example 1. The particles in Comparative Example 5 (110 nm) were too large, and the subsurface stress state deviated significantly from the ideal range (+25.6 MPa), leading to a substantial decrease in the phase transformation toughening effect.

[0070] The effect of the asymmetric air-cooling ratio was verified in Examples 7 (1.2:1) and 8 (1.8:1). Example 7 had a smaller upper / lower air pressure difference, with an upper surface compressive stress of only 120 MPa, slightly lower than the ideal value. Example 8 had a larger upper / lower air pressure difference, but it was still within the effective range, and its performance was comparable to Example 1. The symmetric air-cooling process in Comparative Example 3 resulted in the same upper and lower surface stress (110 MPa), making it impossible to optimize for unilateral impacts, and significantly reducing impact resistance.

[0071] The subsurface stress state of Comparative Example 1 (without rare earth doping) (+18.3 MPa) was significantly higher than the ideal range, indicating that without rare earth doping, ZrO2 partially transforms into the monoclinic phase during the annealing stage, reducing the phase transformation toughening efficiency. The subsurface stress state of Comparative Example 4 (without low-temperature annealing) (+22.4 MPa) further deviated from the ideal range, confirming the key role of the first-stage low-temperature annealing in controlling the precipitation of nanoparticles.

[0072] The results of the multi-point impact test show that all embodiments maintained structural integrity or only had slight cracks after 5 impacts, while all comparative embodiments fractured, proving that the product of the present invention has significant advantages in multi-point impact scenarios.

[0073] The transmittance test results showed that the visible light transmittance of all samples was above 89%, which met the optical performance requirements of architectural glass, indicating that the addition of nanoparticles did not have a negative impact on the light transmittance of the glass.

[0074] The above data fully demonstrates that this invention, through the synergistic design of rare earth-doped Al2O3-ZrO2 nanocomposite precipitates and gradient stress structure, successfully solves the problem of insufficient multi-point impact resistance of traditional tempered glass, achieving a gradient mechanical property of "hard on the surface and tough on the inside," and providing an innovative solution for high-safety application scenarios such as building curtain walls and explosion-proof windows.

[0075] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A high-strength, impact-resistant tempered glass, characterized in that, Rare earth-doped Al2O3-ZrO2 nanocomposite precipitates are uniformly dispersed in the glass matrix. These precipitates are composed of Y... 3+ or Ce 4+ The glass is composed of stabilized tetragonal ZrO2 and spinel-type Al2ZrO5 with a particle size in the nanometer range. The glass has a gradient stress structure, including an upper surface compressive stress layer, a lower surface compressive stress layer, and a subsurface toughness buffer layer located inside the upper surface compressive stress layer and the lower surface compressive stress layer, respectively. The subsurface toughness buffer layer contains the nanocomposite precipitates and is in a state of micro-tensile stress.

2. The high-strength impact-resistant tempered glass according to claim 1, characterized in that, The particle size of the nanocomposite precipitate is 20–80 nm; the compressive stress of the upper surface compressive stress layer is ≥120 MPa, and the compressive stress of the lower surface compressive stress layer is ≥100 MPa; the depth of the subsurface toughness buffer is 30–100 μm, and the stress value of the micro-tensile stress state is +5 to +15 MPa.

3. The high-strength impact-resistant tempered glass according to claim 1, characterized in that, The glass matrix is ​​composed of 68–72 wt% SiO2, 10–14 wt% Al2O3, 8–12 wt% Na2O, 5–7 wt% CaO, and 1–3 wt% MgO, with the balance being unavoidable impurities.

4. The high-strength impact-resistant tempered glass according to claim 1, characterized in that, The rare earth-doped Al2O3-ZrO2 nanocomposite particles were prepared by a coprecipitation-sol-gel coupling method, specifically including the following steps: B1. Prepare a mixed aqueous solution with a total metal ion concentration of 1.1-1.3 mol / L by mixing aluminum nitrate, zirconium oxychloride and rare earth nitrates in a molar ratio of Al:Zr:RE=3:1:(0.05–0.15); B2. Under the conditions of 48-52°C water bath and 700-900rpm stirring, add 25% ammonia water dropwise at a rate of 3mL / min until the pH=8.7-8.9, continue stirring for 1-2h and then let it stand for aging for 12-16h. B3. Centrifuge to separate the precipitate, wash with water until the conductivity is <50μS / cm, and then wash twice with anhydrous ethanol; B4. Disperse the washed precipitate in anhydrous ethanol, add citric acid in a molar amount that is 1.1-1.3 times the total molar amount of metal ions, and stir at 58-62°C for 2-3 hours to form a transparent sol. B5. The sol was dried at 80°C for 12 hours to obtain a dry gel, which was then calcined in a muffle furnace with a programmed temperature increase: the temperature was increased to 300°C at 2-3°C / min and held for 1-1.5 hours, and then increased to 600-650°C at 1.5-2°C / min and held for 2 hours. After natural cooling, the gel was ground through a 200-mesh sieve to obtain rare earth-doped Al2O3-ZrO2 nanocomposite particles.

5. The high-strength impact-resistant tempered glass according to claim 4, characterized in that, The rare earth nitrate mentioned in step B1 is yttrium nitrate [Y(NO3)3·6H2O] or cerium nitrate [Ce(NO3)3·6H2O].

6. A method for preparing high-strength impact-resistant tempered glass, characterized in that, The method for preparing the high-strength impact-resistant tempered glass according to any one of claims 1-5 includes the following steps: C1. Mix the glass matrix batch with an appropriate amount of rare earth-doped Al2O3-ZrO2 nanocomposite particles, melt them in a molten pool at a suitable temperature for a suitable time, and during the process, introduce nitrogen gas for protection and stir for a suitable time. C2. Molten glass is formed into flat glass of a specific thickness by float glass process and then sent to an annealing furnace for annealing; C3. The formed glass is subjected to heating, heat preservation, slow cooling and natural cooling steps to complete the first stage of low temperature annealing; C4. After the annealed glass is heated and kept warm in the tempering furnace, it enters the asymmetric air grid system for cooling. After cooling to below the set temperature, it is taken out of the furnace to obtain high-strength impact-resistant tempered glass.

7. The method for preparing high-strength impact-resistant tempered glass according to claim 6, characterized in that, In step C1, the amount of rare earth-doped Al2O3-ZrO2 nanocomposite particles added is 0.5–2.0 wt%; the melting temperature is 1500–1600°C, the melting time is 60–65 min, the stirring rate is 30–40 rpm, and the stirring time is 40–50 min.

8. The method for preparing high-strength impact-resistant tempered glass according to claim 6, characterized in that, In step C2, the thickness of the float glass is 3–6 mm, and the inlet temperature of the annealing furnace is 570–590°C.

9. The method for preparing high-strength impact-resistant tempered glass according to claim 6, characterized in that, In step C3, the specific parameters for the first stage of low-temperature annealing are as follows: heat to 570-590°C at a heating rate of 3-4°C / min, hold for 45-50 min, then slowly cool to 390-410°C at a rate of 1-2°C / min, and then naturally cool to room temperature; wherein the glass transition temperature Tg≈560°C.

10. The method for preparing high-strength impact-resistant tempered glass according to claim 6, characterized in that, In step C4, the heating temperature of the tempering furnace is 690-710°C, and the holding time is 5-8 minutes; the air pressure on the upper surface of the asymmetric air grid system is 130-140 kPa, the air pressure on the lower surface is 90-100 kPa, the cooling rate ratio is (1.3-1.4):1, and the furnace is removed after cooling to below 75-80°C; The asymmetric air grating system includes an upper air grating and a lower air grating. The nozzle orifice diameter of the upper air grating is 0.8 mm, the spacing is 12 mm, and the air pressure adjustment range is 120–150 kPa. The nozzle orifice diameter of the lower air grating is 1.0 mm, the spacing is 15 mm, and the air pressure adjustment range is 80–100 kPa. The upper and lower air gratings start synchronously, and the cooling time is controlled within 120–150 seconds.

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