A method for polishing the surface of a fluorine-indium glass

Abstract

The application discloses a fluorine-indium glass surface polishing method, and mainly comprises the following steps: using a damping cloth, low load pressure, a cerium oxide (CeO2) polishing solution and a sodium carbonate (Na2CO3) PH regulator to polish the surface of the fluorine-indium glass. The application is a fluorine-indium glass precision machining method based on traditional point gluing and disc processing combined with mechanical chemical polishing technology, realizes high-precision machining of the fluorine-indium glass, and solves the problems of easy corrosion and poor roughness of the fluorine-indium glass. The application has the characteristics of high machining precision and high machining efficiency.

Description

Technical Field

[0001] This invention relates to the processing of optical components, and in particular to a method for surface polishing of fluorine-indium glass. Background Technology

[0002] The mid-infrared 3-5μm band has extremely high application value in the field of modern infrared optoelectronic countermeasures systems. One major method in infrared countermeasures technology is to interfere with and damage incoming missiles by emitting high-energy lasers. The development and application of mid-infrared laser technology and devices are inseparable from the research and development of mid-infrared materials. Among them, fluoride glass, with its low phonon energy, wide infrared transmission band, high rare earth ion solubility, and high damage threshold, is a core key material for the development of mid-infrared fiber laser technology and devices. However, current traditional surface polishing methods for optical components, such as those for quartz glass, microcrystalline glass, crystal, single-crystal silicon, and ceramics, are not very suitable for fluoride glass, especially indium fluoride glass. This material is soft, prone to crystallization and corrosion, and easily scratched, resulting in difficult and inefficient processing. Summary of the Invention

[0003] The purpose of this invention is to provide a surface polishing method for fluorine-indium glass. This method is based on a traditional dispensing and plate-mounting technique combined with chemical mechanical polishing, achieving high-precision, non-destructive processing of fluorine-indium glass and ensuring stable mass production. It features non-destructive processing and high processing efficiency.

[0004] The technical solution of the present invention is as follows:

[0005] Damping cloth is used as a polishing pad to prevent scratches on the surface of fluorinated indium glass, and an alkaline polishing solution is prepared to prevent defects from forming on the surface of fluorinated indium glass.

[0006] The specific implementation steps of the above plan are as follows:

[0007] 1) Cutting of fluorine-indium glass: According to the drawing requirements, a certain tolerance range is set, and a wire cutting machine is used to cut irregular glass into regular shapes with consistent dimensions.

[0008] 2) Two-axis machine rough polishing: Use asphalt to apply adhesive to the fluorine-indium glass plate, ensuring that the glass is in the center of the two-axis machine polishing disc, and then use the two-axis machine for rough polishing. The polishing fluid is 14-50 micron diamond abrasive, and the two-axis machine polishing disc is a copper disc. The rough polishing is completed when the surface of the glass is polished to a plane.

[0009] 3) Prepare the polishing solution: Use deionized water, cerium oxide and sodium carbonate solution to prepare the polishing solution. Cerium oxide powder accounts for 5-20% of the total mass of the polishing solution, with a particle size of 50-500nm. Sodium carbonate solution accounts for 1-3% of the total mass of the polishing solution, with a concentration of 1mol / L. The remainder is deionized water. Stir thoroughly and adjust the pH of the polishing solution to 10-12.

[0010] 4) Single-axis machine fine polishing: Transfer the coarsely polished fluorinated indium glass to a single-axis machine for fine polishing, ensuring that the fluorinated indium glass is in the center of the single-axis machine polishing disc. The single-axis machine polishing disc is a glass disc with a damping cloth polishing pad adhered to its surface. The Shore hardness of the damping cloth is 55-70, the upper disc load is within the pressure range of 0-2kg, the upper disc speed is 100-500rpm / min, and the damping cloth polishing disc speed is 100-500rpm / min. Add the polishing liquid prepared in 3), and polish for 10-60 minutes. During the fine polishing process, the surface quality is checked regularly and observed using an optical microscope.

[0011] 5) Surface roughness inspection: After the fluorine-indium glass surface is polished to be free of defects and scratches, a profilometer and a surface defect detector are used to inspect its surface. If the glass surface quality does not meet the requirements, return to step 4) until the surface quality meets the requirements.

[0012] 6) Polishing the remaining surfaces: Apply a protective film to the fluorine-indium glass surface that meets the surface quality requirements, then flip the fluorine-indium glass over and repeat steps 2)-5) to polish the second surface until all surfaces of the fluorine-indium glass are polished. The polished fluorine-indium glass surface achieves a roughness at the nanometer level.

[0013] Furthermore, in step 2), the particle size of the diamond particles is 28 micrometers.

[0014] Furthermore, in step 3), the cerium oxide powder has a particle size of 350 nm.

[0015] Furthermore, in step 3), the mass ratio of cerium oxide to sodium carbonate solution is 5:1, and the pH value of the polishing solution is 11.

[0016] Furthermore, in step 4), the Shore hardness of the damping cloth is 65, the load pressure on the upper plate is 0 kg, the rotation speed of the upper plate is 200 rpm / min, and the rotation speed of the polishing plate is 250 rpm / min.

[0017] Furthermore, in step 5), the testing standard follows the 20 / 10 surface finish requirements of MIL-O-13830B, the U.S. military standard.

[0018] Furthermore, in step 6), the protective film is a 3M protective film.

[0019] Beneficial technical effects of the present invention:

[0020] 1) This invention provides a non-destructive polishing method for the surface of fluorine-indium glass, including polishing conditions and polishing fluid preparation. This method can achieve nanoscale roughness on the surface of fluorine-indium glass, and the surface is free of scratches and defects. It has the characteristics of simple processing, high efficiency and low cost.

[0021] 2) Damping cloth and low load pressure can prevent surface damage to fluorine-indium glass during polishing. Nano-sized cerium oxide particles and adjustable polishing speed and load pressure within a certain range improve the removal rate, while ensuring the stability of internal stress in the glass and preventing scratches. This condition results in high processing efficiency and is conducive to mass polishing.

[0022] 3) Alkaline polishing solution can generate a passivation layer on the surface of fluoroindium glass, preventing corrosion from deionized water. During the ultra-smooth polishing process, it protects the structural system of fluoroindium glass and prevents defects and crystallization.

[0023] 4) Test results show that the surface roughness RMS of the fluorine-indium glass polished by this method is as low as 2.8 nm, the removal rate is as high as 19.39 μm / min, and the surface is free of damage and defects, with an infrared transmittance of more than 90% in the 2.2-6 μm range. Attached Figure Description

[0024] Figure 1 (a) is the roughness measured by a profilometer before polishing of the fluorine-indium glass surface in Example 1; (b) is the roughness measured by a profilometer after polishing of the fluorine-indium glass surface in Example 1; and (c) is the roughness measured by a profilometer after polishing of the control group in Example 1 with cerium oxide aqueous solution.

[0025] Figure 2 (a) is the roughness measured by a profilometer before polishing of the fluorine-indium glass surface in Example 2; (b) is the roughness measured by a profilometer after polishing of the fluorine-indium glass surface in Example 2; and (c) is the roughness measured by a profilometer after polishing of the control group in Example 2 with cerium oxide aqueous solution.

[0026] Figure 3 (a) is the roughness measured by a profilometer before polishing of the fluorine-indium glass surface in Example 3; (b) is the roughness measured by a profilometer after polishing of the fluorine-indium glass surface in Example 3; and (c) is the roughness measured by a profilometer after polishing of the control group with cerium oxide aqueous solution in Example 3.

[0027] Figure 4 (a) is a SEM image of the fluorine-indium glass surface before polishing in Example 1; (b) is a SEM image of the fluorine-indium glass surface after polishing in Example 1.

[0028] Figure 5 (a) is a SEM image of the fluorine-indium glass surface before polishing in Example 2; (b) is a SEM image of the fluorine-indium glass surface after polishing in Example 2.

[0029] Figure 6 (a) is a SEM image of the fluorine-indium glass surface before polishing in Example 3; (b) is a SEM image of the fluorine-indium glass surface after polishing in Example 3.

[0030] Figure 7This is a comparison chart of the removal rates of indium fluoride glass polishing in Examples 1, 2, and 3.

[0031] Figure 8 These are comparative diagrams of stress birefringence distribution measured by a white light interferometer after polishing of indium fluoride glass in Examples 1, 2, and 3.

[0032] Figure 9 These are comparison charts showing the transmittance of indium fluoride glass surfaces after polishing in Examples 1, 2, and 3. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the scope of protection of the present invention.

[0034] Example 1

[0035] 1) Cutting of fluorine-indium glass: According to the drawing requirements, a certain tolerance range is set, and a wire cutting machine is used to cut irregular glass into regular shapes with consistent dimensions.

[0036] 2) Two-axis machine rough polishing: Apply asphalt to the plate of fluorine-indium glass, ensuring that the glass is in the center of the plate, and then use a two-axis machine for rough polishing. The polishing fluid is 28-micron diamond abrasive, and the polishing plate is a copper plate. The rough polishing is completed when the surface of the glass is polished to a plane.

[0037] 3) Prepare a polishing solution using deionized water, cerium oxide and sodium carbonate solution. Use 30g of cerium oxide powder with an average particle size of 350nm, 6g of sodium carbonate solution and 160g of deionized water. Stir thoroughly and adjust the pH of the polishing solution to 11.

[0038] 4) Single-axis machine fine polishing: Transfer the rough-polished glass to a single-axis machine for fine polishing. The polishing disc is a glass disc with a Shore hardness of 65 damping cloth polishing pad attached to its surface. The upper disc load pressure is 2 kg, the upper disc speed is 400 rpm / min, and the damping cloth polishing disc speed is 450 rpm / min. Add the polishing slurry prepared in 3), and polish for 30 minutes. During the fine polishing process, the surface quality is checked regularly and observed using an optical microscope. A control group is set up. The polishing slurry is a cerium oxide aqueous solution, and other conditions are the same.

[0039] 5) Surface roughness inspection: After the fluorine-indium glass surface is polished to be free of defects and scratches, a profilometer and a surface defect detector are used to inspect the surface. If the surface quality of the glass does not meet the requirements, return to step 4). If the surface quality meets the requirements, apply 3M protective adhesive and then polish the second side, repeating steps 2)-5).

[0040] See attached Figure 1Example 1: Roughness measured by a profilometer before and after polishing the surface of fluorine-indium glass. (a) The roughness before polishing is shown in Figure 1. There are many irregular defects and the roughness is poor. The RMS is 313.392 nm. (b) The surface optical quality after polishing is shown in Figure 2. There are no obvious defects on the surface and the roughness is greatly reduced. The RMS is 2.834 nm. (c) The roughness of fluorine-indium glass after polishing with cerium oxide aqueous solution in the control group is shown in Figure 3. There are a lot of defects on the surface. The RMS is 382.216 nm.

[0041] See attached Figure 4 Example 1: SEM images of the fluorine-indium glass surface before and after polishing. (a) The image shows the SEM image of the surface before polishing, where there are obvious defects on the glass surface. (b) The image shows the SEM image of the surface after polishing, where the surface is smooth and without defects.

[0042] See attached Figure 7 In Example 1, the removal rate of polished fluorine-indium glass was 19.39 μm / min.

[0043] See attached Figure 8 In Example 1, the stress birefringence measured by a white light interferometer after polishing the fluorine-indium glass was 2.53 nm / cm.

[0044] See attached Figure 9 In Example 1, the infrared transmittance in the 2.2-6μm range of the polished fluorine-indium glass was higher than 90% overall, with no obvious defect absorption peaks.

[0045] Example 2

[0046] 1) Cutting of fluorine-indium glass: According to the drawing requirements, a certain tolerance range is set, and a wire cutting machine is used to cut irregular glass into regular shapes with consistent dimensions.

[0047] 2) Two-axis machine rough polishing: Apply asphalt to the plate of fluorine-indium glass, ensuring that the glass is in the center of the plate, and then use a two-axis machine for rough polishing. The polishing fluid is 14-micron diamond abrasive, and the polishing plate is a copper plate. The rough polishing is completed when the surface of the glass is polished to a plane.

[0048] 3) Prepare a polishing solution using deionized water, cerium oxide and sodium carbonate solution. Use 15g of cerium oxide powder with an average particle size of 50nm, 3g of sodium carbonate solution and 100g of deionized water. Stir thoroughly and adjust the pH of the polishing solution to 11.

[0049] 4) Single-axis machine fine polishing: Transfer the rough polished glass to a single-axis machine for fine polishing. The polishing disc is a glass disc with a Shore hardness of 65 damping cloth polishing pad attached to its surface. The upper disc load pressure is 1 kg, the upper disc speed is 300 rpm / min, and the damping cloth polishing disc speed is 350 rpm / min. Add the polishing fluid prepared in 3), and polish for 30 minutes. During the fine polishing process, the surface quality is checked regularly and observed using an optical microscope. A control group is set up. The polishing fluid is a cerium oxide aqueous solution, and other conditions are the same.

[0050] 5) Surface roughness inspection: After the fluorine-indium glass surface is polished to be free of defects and scratches, a profilometer and a surface defect detector are used to inspect the surface. If the surface quality of the glass does not meet the requirements, return to step 4). If the surface quality meets the requirements, apply 3M protective adhesive and then polish the second side, repeating steps 2)-5).

[0051] See attached Figure 2 Example 2: Roughness measured by a profilometer before and after polishing the surface of fluorine-indium glass. (a) The roughness before polishing is shown in Figure 1. There are many irregular defects and the roughness is poor. The RMS is 182.483 nm. (b) The surface optical quality after polishing is shown in Figure 2. There are no obvious defects on the surface and the roughness is greatly reduced. The RMS is 3.194 nm. (c) The roughness of fluorine-indium glass after polishing with cerium oxide aqueous solution in the control group is shown in Figure 3. There are a lot of defects on the surface. The RMS is 414.675 nm.

[0052] See attached Figure 5 Example 2: SEM images of the fluorine-indium glass surface before and after polishing. (a) The image shows the SEM image of the surface before polishing, where there are obvious defects on the glass surface. (b) The image shows the SEM image of the surface after polishing, where the surface is smooth and without defects.

[0053] See attached Figure 7 In Example 2, the removal rate of polished fluorine-indium glass was 15.59 μm / min.

[0054] See attached Figure 8 In Example 2, the stress birefringence measured by a white light interferometer after polishing the fluorine-indium glass was 2.54 nm / cm.

[0055] See attached Figure 9 In Example 2, the infrared transmittance in the 2.2-6μm range of the polished fluorine-indium glass was higher than 90% overall, with no obvious defect absorption peaks.

[0056] Example 3

[0057] 1) Cutting of fluorine-indium glass: According to the drawing requirements, a certain tolerance range is set, and a wire cutting machine is used to cut irregular glass into regular shapes with consistent dimensions.

[0058] 2) Two-axis machine rough polishing: Apply asphalt to the plate of fluorine-indium glass, ensuring that the glass is in the center of the plate, and then use a two-axis machine for rough polishing. The polishing fluid is 50-micron diamond abrasive, and the polishing plate is a copper plate. The rough polishing is completed when the surface of the glass is polished to a plane.

[0059] 3) Prepare a polishing solution using deionized water, cerium oxide and sodium carbonate solution. Use 5g of cerium oxide powder with an average particle size of 500nm, 1g of sodium carbonate solution and 80g of deionized water. Stir thoroughly and adjust the pH of the polishing solution to 11.

[0060] 4) Single-axis machine fine polishing: Transfer the rough-polished glass to a single-axis machine for fine polishing. The polishing disc is a glass disc with a Shore hardness of 65 damping cloth polishing pad attached to its surface. The upper disc is unloaded and rotates at 150 rpm / min, while the damping cloth polishing disc rotates at 200 rpm / min. Add the polishing slurry prepared in step 3), and polish for 30 minutes. During the fine polishing process, the surface quality is checked periodically using an optical microscope. A control group is also set up. The polishing slurry is a cerium oxide aqueous solution, and all other conditions are the same.

[0061] 5) Surface roughness inspection: After the fluorine-indium glass surface is polished to be free of defects and scratches, a profilometer and a surface defect detector are used to inspect the surface. If the surface quality of the glass does not meet the requirements, return to step 4). If the surface quality meets the requirements, apply 3M protective adhesive and then polish the second side, repeating steps 2)-5).

[0062] See attached Figure 3 Example 3: Roughness measured by a profilometer before and after polishing the surface of fluorine-indium glass. (a) The roughness before polishing is shown in Figure 1. There are many irregular defects and the roughness is poor. The RMS is 221.744 nm. (b) The surface optical quality after polishing is shown in Figure 2. There are no obvious defects on the surface and the roughness is greatly reduced. The RMS is 3.174 nm. (c) The roughness of fluorine-indium glass after polishing with cerium oxide aqueous solution in the control group is shown in Figure 3. There are a lot of defects on the surface. The RMS is 350.636 nm.

[0063] See attached Figure 6 Example 3: SEM images of the fluorine-indium glass surface before and after polishing. (a) is the SEM image of the surface before polishing, where there are obvious defects on the glass surface. (b) is the SEM image of the surface after polishing, where the surface is smooth and without defects.

[0064] See attached Figure 7 In Example 3, the removal rate of polished fluorine-indium glass was 12.41 μm / min.

[0065] See attached Figure 8 In Example 3, the stress birefringence measured by a white light interferometer after polishing the fluorine-indium glass was 2.56 nm / cm.

[0066] See attached Figure 9 In Example 3, the infrared transmittance in the 2.2-6μm range of the polished fluorine-indium glass was higher than 90% overall, with no obvious defect absorption peaks.

Claims

1. A method for polishing the surface of indium fluoride glass, characterized in that, Includes the following steps: 1) Cutting of fluoroindium fluoride glass: Set the tolerance range according to the drawing requirements, and use a wire cutting machine to cut the fluoroindium fluoride glass into regular shapes with consistent dimensions; 2) Two-axis machine rough polishing: The fluorinated indium glass is fixed in the middle of the two-axis machine polishing disc by using an asphalt-coated upper plate. A polishing liquid containing 14-50 micron diamond grit is used, and a copper disc is used as the polishing disc for rough polishing until the surface of the fluorinated indium glass forms a flat surface. 3) Prepare the polishing solution: Use deionized water, cerium oxide powder and sodium carbonate solution to prepare the polishing solution. The cerium oxide powder accounts for 5-20% of the total mass of the polishing solution and the particle size of the cerium oxide powder is 50-500nm. The sodium carbonate solution accounts for 1-3% of the total mass of the polishing solution and the concentration is 1mol / L. The remainder is deionized water. Stir thoroughly and adjust the pH of the polishing solution to 10-12. 4) Single-axis machine fine polishing: Transfer the coarsely polished fluoropolymer glass to the center of the single-axis machine polishing disc. Use a glass disc with a damping cloth polishing pad as the polishing disc for fine polishing. The Shore hardness of the damping cloth is 55-70, the load pressure of the upper disc is 0-2kg, the upper disc speed is 100-500rpm / min, and the polishing disc speed is 100-500rpm / min. Add the polishing liquid prepared in 3), and the polishing time is 10-60min. During the polishing time, the surface quality of the fluoropolymer glass is checked regularly. 5) Surface roughness inspection: After the fluorine-indium glass surface is polished to be free of defects and scratches, a profilometer and a surface defect detector are used to inspect its surface. If the glass surface quality does not meet the requirements, return to step 4) to continue polishing until the surface quality meets the requirements. 6) Polishing the remaining surfaces: Apply a protective film to the fluorine-indium glass surface that meets the surface quality requirements, then flip the fluorine-indium glass over and repeat steps 2)-5) to polish the second surface until all surfaces of the fluorine-indium glass are polished. The polished fluorine-indium glass surface achieves a roughness at the nanometer level.

2. The surface polishing method for fluorine-indium glass according to claim 1, characterized in that, In step 2), the particle size of the diamond particles is 28 micrometers.

3. The surface polishing method for fluorine-indium glass according to claim 1, characterized in that, In step 3), the cerium oxide powder has a particle size of 350 nm.

4. The surface polishing method for fluorine-indium glass according to claim 1, characterized in that, In step 3), the mass ratio of cerium oxide to sodium carbonate solution is 5:1, and the pH value of the polishing solution is 11.

5. The surface polishing method for fluorine-indium glass according to claim 1, characterized in that, In step 4), the damping cloth has a Shore hardness of 65, the upper plate load pressure is 2 kg, the upper plate rotation speed is 400 rpm / min, and the polishing plate rotation speed is 450 rpm / min.

6. The surface polishing method for fluorine-indium glass according to claim 1, characterized in that, In step 6), the protective film is a 3M protective film.

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