Composite strengthening method for large-size hemispherical glass

Abstract

The invention discloses a large-size hemispherical glass composite strengthening method which comprises the following steps: (1) carrying out laser-induced crystallization treatment on an original inch hemispherical glass sheet, specifically, corroding the original glass sheet with hydrofluoric acid, coating a light absorption layer on the surface of the glass, and carrying out glass surface crystallization processing by adopting laser to obtain a crystallized glass sheet; finally, the glass is put into an annealing furnace for annealing treatment; and (2) cleaning the surface of the glass subjected to laser induction treatment, putting the glass into a vacuum or inert gas environment, scanning the surface of the glass by using a high-energy electron beam generated by an accelerator, and finally putting the glass into an annealing furnace for annealing treatment. The obtained large-size hemispherical tempered glass has the advantages of being excellent in mechanical performance, free of thermal deformation risk in the strengthening process, designable in crystal phase and the like, and in addition, the composite strengthening method has the advantages of being energy-saving and environment-friendly in process, safe, reliable and the like, and has good industrial application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of glass strengthening, and in particular to a composite strengthening method for large-size hemispherical glass. Background Art

[0002] Large-scale hemispherical glass can serve as observation windows for space stations. In near-Earth space, where the station travels at near-first cosmic velocity, small, high-speed space debris can travel much faster than a bullet. Therefore, the strength of large-scale hemispherical glass used in space stations must be significantly higher than that of terrestrial bulletproof glass. Therefore, enhancing the mechanical properties of hemispherical glass through post-processing and strengthening is an inevitable choice for improving the safety of hemispherical glass.

[0003] Glass is a typically brittle material. When used as a key structural component, it requires strengthening processing to enhance its mechanical properties and thereby ensure structural reliability during engineering service. Currently, the design principle for improving glass strength is to create a pre-stressed layer on the glass surface through strengthening processing, inhibiting the inward expansion of microcracks and the resulting stress concentration. Depending on the strengthening principle, there are two main types: chemical strengthening and thermal strengthening. Chemical strengthening is primarily used for thin glass under 3 mm. For hemispherical glass thicker than 3 mm, the only option is thermal strengthening, which is a physical tempering process.

[0004] For large-sized hemispherical glass with a diameter greater than 1000mm, physical tempering has the following technical difficulties:

[0005] (a) When tempering large sizes, the glass will deform under the influence of its own weight, and the temperature inside and outside the ball will be inconsistent, and the temperature uniformity will not meet the requirements;

[0006] (b) When the wind grid cools the spherical glass, the wind pressure is inconsistent inside and outside, and at different locations on the spherical surface. This leads to uneven stress distribution on the glass surface, resulting in substandard tempered strength and substandard particle size after breakage. Currently, there is no better solution for the physical tempering of large-sized hemispherical glass. Summary of the Invention

[0007] Aiming at the defects in the existing technology of physical tempering of large-sized hemispherical glass, such as deformation affected by dead weight and uneven stress distribution on the surface of the shaped glass, the present invention proposes a composite strengthening method for large-sized hemispherical glass.

[0008] The technical solution adopted by the present invention is as follows:

[0009] A large-size hemispherical glass composite strengthening method comprises the following steps:

[0010] S1. Performing laser-induced crystallization on a glass sheet. Specifically, a large-sized hemispherical glass sheet larger than 1000 mm is etched with hydrofluoric acid, a light-absorbing layer is coated on the glass surface, laser is used to crystallize the glass surface, and finally the glass is placed in an annealing furnace for annealing.

[0011] S2. Electron beam irradiation strengthening treatment is performed on large-sized hemispherical glass originals. First, the glass surface after laser induced treatment is cleaned, the glass is placed in a vacuum or inert gas environment, and the high-energy electron beam generated by the accelerator is used to scan the glass surface. Finally, the glass original is placed in an annealing furnace for annealing treatment.

[0012] Furthermore, in the large-sized hemispherical glass original piece in step S1, one or a combination of nucleating agents TiO2, ZrO2, SnO2, Ta2O5, and MoO3 is added to the glass oxide composition, and the total content of the nucleating agents is 0.15 wt.%-1.2 wt.%; the laser wavelength used is 600-800 nm, the single pulse energy is 3-5 μJ, the repetition frequency is 220-250 kHz, and the irradiation time is 1-3 s.

[0013] Furthermore, the concentration of hydrofluoric acid used in step S1 is 5 wt.%-8 wt.%, and the etching time is 30s-80s.

[0014] Furthermore, the light absorbing layer coated on the surface of the glass sheet in step S1 is a carbon nanotube suspension, and the coating thickness is greater than 200 nm.

[0015] Furthermore, the crystal form of the crystallized surface of the glass sheet in step S1 is one or a combination of cordierite crystal form, spinel crystal form, and β-quartz crystal form.

[0016] Furthermore, in step S1, the original glass sheet is annealed in a nitrogen atmosphere at 250-300° C. for 30 minutes.

[0017] Furthermore, the vacuum degree of the vacuum environment in step S2 is less than 10 -4 Pa, high-energy electron beam scans the surface of the glass original for 1-10 minutes, the electron energy is 0.5-2.5 MeV, and the beam current density is 0.5-10 mA / cm 2 The glass sheet was annealed in a nitrogen atmosphere at 250-300°C for 30 minutes.

[0018] The laser-induced crystallization method of the present invention uses laser induction to microcrystallize the glass surface. The resulting crystals are transparent and do not affect the glass's transmittance. Furthermore, the laser-induced microcrystallization method can produce uniform microcrystals on the inner and outer surfaces of the glass hemisphere. The addition of a nucleating agent to the glass oxide composition allows the glass to form crystal nuclei under laser induction. Further growth of the nuclei leads to microcrystallization of the glass surface. Electron beam irradiation strengthening, on the other hand, rearranges the atoms in the irradiated area of ​​the glass surface, forming a more compact silicon-oxygen network structure. While the surface densifies, the volume shrinks, but is constrained by the underlying unirradiated glass, generating residual compressive stress in the surface layer (similar to the principle of physical tempering), significantly inhibiting the propagation of microcracks.

[0019] Beneficial effects of the present invention:

[0020] By combining laser-induced crystallization and electron beam irradiation, the present invention achieves a composite strengthening method that prevents temperatures from exceeding 500°C during glass processing, whereas alkali-free aluminosilicate glass, during physical tempering, reaches temperatures 50°C below its softening point, i.e., 650-850°C. This composite strengthening method effectively prevents deformation of glass under its own weight at high temperatures. Furthermore, laser-induced crystallization and electron beam irradiation are highly effective for strengthening complex glass shapes. Both strengthening methods differ significantly from traditional physical tempering, avoiding the drawbacks of wind grid cooling, which can lead to uneven stress distribution and low yields, resulting from varying cooling rates in different glass regions. DETAILED DESCRIPTION

[0021] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only a portion of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments derived by persons of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0022] The following experimental methods are conventional methods unless otherwise specified.

[0023] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0024] Example

[0025] The present invention discloses a large-sized hemispherical glass sheet with a diameter of 1500 mm and a thickness of 10 mm. The glass sheet has the following composition: SiO2: 65-80%, Al2O3: 15-20%, B2O3: 1-5%, MgO: 0.5-4%, CaO: 0.5-8%, SrO: 0.5-3%, BaO: 5-10%. The nucleating agent in the glass sheet is a combination of TiO2 and SnO2, and the amount of the nucleating agent added is 1.0 wt.% of the total amount of glass.

[0026] The above-mentioned large-size hemispherical glass composite strengthening method includes the following steps:

[0027] S1. The glass substrate is subjected to laser-induced crystallization treatment. Specifically, the glass substrate is etched with 5% wt.% hydrofluoric acid for 30 seconds, and a 200 nm thick carbon nanotube suspension (light-absorbing layer) is coated on the glass surface. After drying, the glass surface is crystallized using a laser. The crystal forms formed after crystallization are spinel and β-quartz. The laser wavelength used is 600 nm, the single pulse energy is 4 μJ, the repetition rate is 220 kHz, and the irradiation time is 3 seconds.

[0028] Finally, the glass was placed in an annealing furnace under a nitrogen environment and annealed at 280°C for 30 minutes.

[0029] S2. Electron beam irradiation strengthening treatment is performed on the glass. First, the surface of the glass after laser induction treatment is cleaned, and the original glass is placed in a vacuum environment with a vacuum degree of 10 -4 Pa, an accelerator was used to generate a high-energy electron beam that scanned the glass surface for 8 minutes. The electron energy was 2.0 MeV and the beam current density was 8.0 mA / cm 2 Finally, the glass was placed in a nitrogen atmosphere annealing furnace and annealed at 280°C for 30 minutes.

[0030] After taking out the sample for testing, the transmittance = 92.1% (visible light range 390nm ~ 780nm), thermal shock resistance ΔT = 200℃ (±100℃), bending strength = 500Mpa, deflection δ = 1-10mm.

[0031] The test results show that the resulting large-scale hemispherical tempered glass exhibits excellent mechanical, optical, and thermodynamic properties, with no risk of thermal deformation during the tempering process and customizable crystal phases. This makes it suitable for use as a key material for structural components, ensuring structural reliability during engineering service. Furthermore, the composite tempering method proposed in this application is energy-efficient, environmentally friendly, safe, and reliable, demonstrating promising industrial application prospects. In summary, this invention possesses significant application value in the field of radioactive waste treatment technology.

[0032] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. Throughout this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0033] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

Claims

1. A large-size hemispherical glass composite strengthening method, characterized in that The following steps are involved: S1. Performing laser-induced crystallization on a hemispherical glass sheet. Specifically, the hemispherical glass sheet larger than 1000 mm is etched with hydrofluoric acid, a light-absorbing layer is coated on the glass surface, and the surface of the glass sheet is crystallized using a laser. Finally, the glass sheet is placed in an annealing furnace for annealing. S2. Electron beam irradiation strengthening treatment is performed on large-sized hemispherical glass sheets. First, the glass surface after laser induced treatment is cleaned, and the glass is placed in a vacuum or inert gas environment. The surface of the glass sheet is scanned with a high-energy electron beam generated by an accelerator, and finally the glass sheet is placed in an annealing furnace for annealing treatment.

2. The method for composite strengthening of large-sized hemispherical glass according to claim 1, characterized in that: The large-sized hemispherical glass original piece in step S1 has one or a combination of nucleating agents TiO2, ZrO2, SnO2, Ta2O5, and MoO3 added to the glass oxide composition, and the nucleating agent accounts for 0.15 wt.%-1.2 wt.% of the total glass content; the laser wavelength used is 600-800 nm, the single pulse energy is 3-5 μJ, the repetition frequency is 220-250 kHz, and the irradiation time is 1-3 s.

3. The method for composite strengthening of large-sized hemispherical glass according to claim 1, characterized in that: The concentration of hydrofluoric acid used in step S1 is 5 wt.%-8 wt.%, and the etching time is 30s-80s.

4. The method for composite strengthening of large-sized hemispherical glass according to claim 1, characterized in that: In step S1 , the light absorbing layer coated on the surface of the glass sheet is a carbon nanotube suspension, and the coating thickness is greater than 200 nm.

5. The method for composite strengthening of large-sized hemispherical glass according to claim 1, characterized in that: The crystal form of the crystallized surface of the glass sheet in step S1 is one of cordierite crystal form, spinel crystal form, and β-quartz crystal form, or a combination of several of them.

6. The method for composite strengthening of large-sized hemispherical glass according to claim 1, characterized in that: In step S1, the glass sheet is annealed in a nitrogen atmosphere at 250-300° C. for 30 minutes.

7. The method for composite strengthening of large-sized hemispherical glass according to claim 1, characterized in that: The vacuum degree of the vacuum environment in step S2 is less than 10 -4 Pa, high-energy electron beam scans the surface of the glass original for 1-10 minutes, the electron energy is 0.5-2.5 MeV, and the beam current density is 0.5-10 mA / cm 2 The glass sheet was annealed in a nitrogen atmosphere at 250-300°C for 30 minutes.