Dry ice sand blasting-chemical dissolution-ultrasonic collaborative cleaning process for nano aluminum oxide coating part

Abstract

The invention relates to the technical field of surface treatment, discloses a dry ice sand blasting-chemical dissolution-ultrasonic collaborative cleaning process for a nano aluminum oxide coating part, and aims to overcome the defects of an existing cleaning technology in the aspects of removing a complex deposited film, protecting the coating integrity and improving the cleaning efficiency. The method comprises the steps of isopropanol soaking treatment, flowing pure water flushing, hot water soaking treatment, carbon dioxide dry ice sand blasting treatment, chemical cleaning of a niflumic acid mixed solution, high-pressure water washing, ultrasonic cleaning and the like. By the adoption of the technical scheme, the efficient, thorough and lossless cleaning effect can be achieved, and the high-standard requirement for cleaning of the nanometer aluminum oxide coating part in the modern industry is met.

Description

Technical Field

[0001] This invention belongs to the field of surface treatment technology, specifically relating to a dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components. Background Technology

[0002] With the widespread application of nano-alumina coatings in high-end manufacturing fields such as semiconductor manufacturing, optical components, and precision instruments, the impact of their surface cleanliness on device performance and lifespan is becoming increasingly prominent. Nano-alumina coatings possess high hardness, excellent insulation, and chemical stability, and are often used for surface protection of critical functional components. However, their micro-nano structures readily adsorb oil, organic residues, inorganic particles, and complex deposited films. Incomplete cleaning can directly lead to decreased interfacial adhesion, deterioration of optical transmittance, or drift in electrical properties. Therefore, there is an urgent need for a precision cleaning process that can efficiently remove various contaminants without damaging the nanoscale coating structure to meet the stringent surface cleanliness requirements of modern high-precision manufacturing.

[0003] The cleaning process for nano-alumina coated components needs to address the triple objectives of physical stripping, chemical dissolution, and deep cleaning. Traditional cleaning methods often employ single approaches, such as relying solely on organic solvent immersion, high-pressure water rinsing, or conventional ultrasonic cleaning, which are insufficient to handle multi-component, strongly adhered complex contaminants. Especially when contaminants form dense deposits or are embedded in microporous structures, a single cleaning mechanism often fails to achieve complete removal and is prone to causing coating peeling, lattice damage, or increased surface roughness due to mechanical stress or highly corrosive reagents, thereby affecting its functional performance.

[0004] Current technologies for cleaning nano-alumina coatings still have significant shortcomings. On the one hand, while dry ice blasting offers advantages such as low temperature and residue-free physical impact, its ability to remove chemically bonded films is limited. On the other hand, while conventional acid washing processes can dissolve some inorganic deposits, the selectivity of nitric acid or hydrofluoric acid alone is insufficient, easily corroding the substrate or damaging the coating integrity. Furthermore, although ultrasonic cleaning can penetrate deep into microstructures, its efficiency in peeling off stubborn films is low without pretreatment. Especially when dealing with ultrathin coatings only tens to hundreds of nanometers thick, existing cleaning processes lack multi-mechanism synergistic design, making it difficult to maintain the structural stability and surface finish of the coating while ensuring thorough cleaning. These problems collectively constitute the core technological bottleneck faced by nano-alumina coated components in high-cleanliness applications, urgently requiring a synergistic cleaning process that integrates physical impact, targeted chemical dissolution, and cavitation deep cleaning to overcome these challenges. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated parts, which can effectively solve the problems in the background art. To achieve the above objectives, the present invention provides the following technical solution: a dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components, comprising the following steps: Step S110, isopropanol immersion treatment of the nano-alumina coated components at room temperature for 30 minutes; Step S120, rinsing the surface of the components after isopropanol immersion with flowing pure water for at least 2 minutes; Step S130, immersion treatment of the components in hot water at room temperature for 30 minutes; Step S140, rinsing the surface of the components again with flowing pure water for at least 2 minutes; Step S150, blasting the surface of the components with a carbon dioxide dry ice blasting device at a blasting pressure range of 25 to 45 psi; Step S160, drying the surface of the blasted components with compressed air; Step S170, preparing a solution of 2% to 5% nitric acid and 0.A mixed acid solution consisting of 5% to 2% hydrofluoric acid and the remainder pure water is used to chemically clean the component to remove microscopic deposits on the surface; in step S180, the component is immersed three times in a pure water bath to remove residual acid from the surface; in step S190, a high-pressure water gun with a pressure of 800 to 1000 psi is used to thoroughly rinse the surface of the component, including all small holes and both sides, for a rinsing time of not less than 2 minutes; in step S200, a nitric acid solution with a concentration of 2% to 5% is prepared to clean the component to form an oxide protective film on the surface; in step S210... Step S220: Immerse the component three times in a pure water bath to remove residual nitric acid from the surface; Step S230: Repeat the high-pressure water washing step, rinsing the component surface with an 800 to 1000 psi high-pressure water gun for at least 2 minutes; Step S240: Clean the component in a pure water ultrasonic cleaning tank with an ultrasonic power density of 4 to 8 watts per square inch for 20 to 30 minutes; Step S250: Dry the component with filtered compressed air until there is no water residue on the surface; Step S26: Rinse the component surface with running pure water. Step S260: Rinse the surface for at least 2 minutes; Step S270: Perform ultrasonic cleaning again with pure water, with an ultrasonic power density of 4 to 8 watts per square inch and an operation time of 20 to 30 minutes; Step S280: Perform a final rinse on the surface of the component with flowing pure water for at least 2 minutes; Step S290: Use a liquid particle testing instrument to perform ultrasonic excitation particle and filtration circulation treatment tests on the component to detect the overall particle level of all surfaces; Step S2011: Use high-purity nitrogen to dry the component until there are no water marks on the surface. Step S300: Place the component in a cleanroom oven for drying at a temperature ranging from 80 to 100 degrees Celsius for 2 hours. Step S310: Perform a visual inspection on the dried component. Step S320: Conduct a final quality control inspection, verifying the component's appearance. Step S330: Use an ultraviolet lamp to inspect the component surface to ensure there are no fluorescent defects. Step S340: Use a QIII particle detector to check the particle level on the component surface. Step S350: Seal the qualified components in double-layer vacuum polyethylene bags.

[0006] Preferably, the isopropanol immersion treatment in step S110 serves to dissolve and remove organic oil and some polar contaminants from the surface of the component. The isopropanol has a purity of not less than 99.7% to ensure that it is non-corrosive to the nano-alumina coating and does not introduce secondary pollution. The immersion process is carried out in a sealed container to avoid solvent evaporation leading to concentration changes and environmental exposure.

[0007] Furthermore, in step S130, the hot water immersion treatment maintains the water temperature within the range of 45 to 60 degrees Celsius. This temperature range can effectively soften the composite membrane deposited in the micropores of the nano-coating and reduce its binding energy with the coating surface. The hot water is ultrapure water that has undergone ion exchange and reverse osmosis treatment, and its resistivity is not less than 18 megohm-cm, in order to prevent inorganic ions from redepositing during the softening process.

[0008] Furthermore, in step S150, the carbon dioxide dry ice blasting treatment uses dry ice particles with a particle size distribution between 0.5 and 3 mm, a blasting distance controlled between 100 and 300 mm, and a blasting angle at a 15 to 45 degree angle relative to the normal to the component surface. Upon impact, the dry ice particles undergo a phase transition and sublimate, generating a localized low-temperature effect of approximately -78.5 degrees Celsius. This low-temperature effect embrittles contaminants. Simultaneously, the micro-explosion energy generated by the expansion of the dry ice, combined with the mechanical impact force, physically removes contaminants from the nanoscale pores. Moreover, no solid residue remains after the dry ice sublimates, avoiding secondary pollution.

[0009] Preferably, in the nitric acid chemical cleaning of step S170, the concentration of nitric acid in the mixed acid solution is preferably 3%, and the concentration of hydrofluoric acid is preferably 1%. This ratio is based on the synergistic effect of the strong oxidizing property of nitric acid and the specific dissolving ability of hydrofluoric acid on silicate deposits. The action time of the mixed acid solution is controlled at 5 to 10 minutes, and the operating temperature is maintained at 20 to 25 degrees Celsius. The coating thickness change is monitored in real time by an online ellipsometry. When the etching rate exceeds 0.08 nanometers per minute, pure water is automatically added to dilute the acid solution so that the rate is stabilized in the range of 0.05-0.1 nanometers per minute.

[0010] Furthermore, in the high-pressure water washing operations of steps S190 and S220, the water jet pressure is set to 900 psi, and the water jet nozzle adopts a fan-shaped wide-angle design with a coverage angle of 60 to 80 degrees. The physical scouring effect of the high-pressure water washing can effectively remove the loose residual particles and reaction products after chemical cleaning. Especially for microstructures with pore sizes greater than 1 micrometer, the cleaning efficiency can reach more than 95%.

[0011] Furthermore, in the ultrasonic cleaning of steps S230 and S260, the ultrasonic frequency is set to 40 kHz, and the peak pressure of the microjets generated by the cavitation effect exceeds 1000 atmospheres. When the cavitation bubbles collapse near the surface of the nano-coating, the resulting shear force can penetrate into pores with a size of 0.1 to 10 micrometers, peeling the attached particles from the substrate. The product of the ultrasonic power density and the action time is controlled within the range of 160 to 240 watts per minute per square inch to ensure that the cavitation intensity is within the effective cleaning threshold and does not cause cavitation erosion on the coating surface.

[0012] Preferably, the liquid particle test in step S280 is based on the principle of applying ultrasonic waves with a frequency of 80 to 120 kHz to the test liquid to excite the particles adsorbed on the surface of the component. Then, the test liquid is circulated and filtered using a filter membrane with a pore size of 0.1 micrometers, and the particle concentration C (unit: particles / mL) of the filtered liquid is measured by a laser particle counter. The number of particles per square centimeter is calculated according to the formula 'surface particle density = C × V / S' based on the area S (unit: cm²) of the component immersed in the test liquid and the liquid volume V (unit: mL).

[0013] Furthermore, the dust-free oven drying in step S300 has an air cleanliness level of 5 as specified in ISO14644-1, an airflow organization of vertical laminar flow, and an air velocity of 0.3 to 0.5 meters per second. The drying process not only removes surface adsorbed water, but the hot air convection can also promote the condensation of hydroxyl groups on the coating surface, thereby enhancing the density and chemical stability of the alumina coating.

[0014] Furthermore, the ultraviolet detection in step S330 uses a 365 nm ultraviolet light source to irradiate the component surface in a dark room. The background fluorescence intensity of the nano-alumina coating at this wavelength is less than 10 photons per second per square centimeter. If a local fluorescence intensity exceeds this threshold, organic residue is determined to be present, and the following steps must be repeated: Wipe the defective area three times unidirectionally with a non-woven fabric soaked in 99.7% isopropanol, with a 10-second interval between each wipe; then blow with 0.3 MPa compressed air at a 45° angle from 50 mm above the surface for 20 seconds. Repeat until the fluorescence intensity is below the threshold.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0016] 1. By using a sequential process of hot water immersion and dry ice blasting, the softening and physical stripping of the deposited film were achieved in synergy, overcoming the shortcomings of single physical cleaning in removing chemically bonded contaminants, and increasing the film removal rate to over 98%.

[0017] 2. Chemical cleaning was performed using a nitrofluoric acid mixture with a specific ratio. Under the oxidation of nitric acid and the specific dissolution of hydrofluoric acid, the inorganic deposited film was selectively removed, while the corrosion rate of the coating was controlled to less than 6 nanometers per hour, ensuring the structural integrity of the nano-coating.

[0018] 3. The multi-round synergistic operation of high-pressure water washing and ultrasonic cleaning combines the macroscopic scouring of high-pressure water jets with the microscopic cleaning effect of ultrasonic cavitation, which significantly improves the removal efficiency of submicron particles embedded deep in micro-nano structures, reducing the number of residual particles to less than 5 per square centimeter.

[0019] 4. It integrates multiple online quality control methods such as liquid particle testing, ultraviolet detection, and particle detection, realizing real-time monitoring of the cleaning process and quantitative evaluation of cleaning quality, ensuring that the components leaving the factory meet the stringent standards for surface cleanliness in the semiconductor manufacturing industry. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall technical solution architecture of the dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components proposed in this invention;

[0021] Figure 2 This is a schematic diagram of the core principle framework of the dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning method in this invention;

[0022] Figure 3 This is a logical flow diagram of the pretreatment and physical cleaning stages in this invention;

[0023] Figure 4 This is a schematic diagram of the multi-level interaction relationship and data flow between the chemical cleaning and post-treatment stages in this invention. Detailed Implementation

[0024] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[0025] Example 1

[0026] In the maintenance workshop for critical components of semiconductor manufacturing equipment, a combined dry ice blasting-chemical dissolution-ultrasonic cleaning process is implemented for the inner wall components of process chambers with a nano-alumina coating. (See also...) Figure 1 This process comprises four main technical modules: pretreatment, physical cleaning, chemical cleaning, and post-treatment. The pretreatment stage begins with isopropanol immersion of the nano-alumina coated components. The components are completely submerged in an isopropanol solution within a sealed container, with the treatment temperature maintained between 20 and 25 degrees Celsius, and the immersion time strictly controlled to 30 minutes. The isopropanol has a purity of no less than 99.7%, and its hydroxyl groups form hydrogen bonds with organic contaminants, effectively dissolving and removing organic oil and polar contaminants from the component surface. The sealed container is made of stainless steel and equipped with a sealing cap to prevent solvent evaporation and concentration changes, while also preventing particulate contaminants from the environment from entering the treatment solution.

[0027] After isopropanol immersion, the components undergo a flowing pure water rinsing process. Ultrapure water with a resistivity of at least 18 megohm-cm is used, forming a uniform water curtain through a porous distributor to thoroughly rinse the component surface. The water flow rate is maintained at 2 to 3 meters per second, and the rinsing time is no less than 2 minutes. The rinsed wastewater is collected through a dedicated pipeline to a neutralization treatment system to ensure compliance with environmental emission standards. Following this, a hot water immersion treatment is performed. The components are transferred to a constant-temperature hot water bath, with the water temperature precisely controlled within the range of 45 to 60 degrees Celsius. The hot water is ultrapure water that has undergone dual treatment of ion exchange and reverse osmosis, with a dissolved oxygen content of less than 10 micrograms per liter. The immersion time is maintained for 30 minutes. This temperature range effectively softens the composite membrane deposited within the micropores of the nano-coating, reducing the bonding energy between the membrane and the coating surface from the initial 200 millijoules per square meter to below 50 millijoules per square meter.

[0028] A second rinse with running pure water, using the same process parameters as the first rinse, is performed to ensure thorough removal of contaminants dissolved during hot water immersion. After rinsing, the process proceeds to dry ice blasting. See [link / reference] Figure 2 The process employs a carbon dioxide dry ice blasting system. The dry ice particles, with a particle size distribution between 0.5 and 3 mm, are accelerated by compressed air to an impact pressure of 25 to 45 psi. The blasting distance is controlled within the range of 100 to 300 mm, and the blasting angle is at an angle of 15 to 45 degrees relative to the normal to the component surface. Upon impact, the dry ice particles undergo a phase transition and sublimation, generating a localized low-temperature effect of approximately -78.5 degrees Celsius, increasing the embrittlement of contaminants by more than three times. Simultaneously, the micro-explosion energy generated by the expansion of the dry ice, combined with the mechanical impact force, achieves the physical stripping of contaminants from the nanoscale pores, with a stripping efficiency of 98.5%. No solid residue remains after dry ice sublimation, avoiding secondary pollution that may occur with traditional blasting media.

[0029] Immediately after sandblasting, the component surface is dried using filtered compressed air. The compressed air undergoes three-stage filtration, ensuring a particulate matter content below 0.01 mg / m³ and a dew point temperature below -40°C. The drying process continues until no visible water marks remain on the surface, ensuring the effectiveness of subsequent chemical cleaning. Next, a mixed acid solution is prepared, consisting of 2% to 5% nitric acid, 0.5% to 2% hydrofluoric acid, and the remainder pure water, with a preferred ratio of 3% nitric acid to 1% hydrofluoric acid. The mixed acid solution is used to chemically clean the component at 20 to 25°C for 5 to 10 minutes. The strong oxidizing properties of nitric acid convert metallic impurities into soluble salts, while hydrofluoric acid specifically dissolves silicate deposits; their synergistic effect removes the microscopic deposited film on the surface. The etching rate of the hydrofluoric acid on the alumina coating is monitored in real-time, ensuring it is below 0.1 nanometers per minute to guarantee the integrity of the coating structure.

[0030] Immediately after chemical cleaning, the components are immersed in ultrapure water three times. Each immersion lasts at least 5 minutes, with slight shaking of the water tank during immersion to enhance the displacement effect. After three immersions, the surface of the components is thoroughly rinsed using a high-pressure water gun with a pressure of 800 to 1000 psi. The high-pressure water gun nozzle features a wide-angle fan-shaped design with a coverage angle of 60 to 80 degrees, ensuring that the rinsing range covers all small holes and both sides. The rinsing time is at least 2 minutes. The physical scouring effect of the water jet effectively removes loosened residual particles and reaction products after chemical cleaning. For microstructures with pore sizes larger than 1 micrometer, the cleaning efficiency reaches over 95%.

[0031] The components are then cleaned a second time with a 2% to 5% nitric acid solution, preferably 3%. The cleaning time is controlled to be 3 to 5 minutes, forming a dense protective oxide film on the surface of the nano-alumina coating, with a film thickness controlled within the range of 2 to 5 nanometers. The components are then immersed three times in pure water to remove any residual nitric acid. The high-pressure water washing step is repeated, using an 800 to 1000 psi high-pressure water gun to rinse the component surface for at least 2 minutes. This completes all procedures in the chemical cleaning stage.

[0032] In the ultrasonic cleaning stage, the components are placed in a pure water ultrasonic cleaning tank for the first ultrasonic cleaning. The ultrasonic frequency is set to 40 kHz, the power density is controlled between 4 and 8 watts per square inch, and the operation time is 20 to 30 minutes. The microjets generated by the ultrasonic cavitation effect have peak pressures exceeding 1000 atmospheres. The shear force generated when cavitation bubbles collapse near the surface of the nano-coating can penetrate into pores with sizes of 0.1 to 10 micrometers, peeling the attached particles from the substrate. The product of ultrasonic power density and action time is strictly controlled within the range of 160 to 240 watts per minute per square inch to ensure that the cavitation intensity is within the effective cleaning threshold and does not cause cavitation erosion on the coating surface.

[0033] After ultrasonic cleaning, the components are dried with filtered compressed air until no water remains on the surface. Next, the surface is rinsed with running pure water for at least 2 minutes. A second ultrasonic cleaning with pure water is then performed, maintaining an ultrasonic power density of 4 to 8 watts per square inch for 20 to 30 minutes. This second ultrasonic cleaning primarily targets any tiny particles that may have redistributed after the first cleaning, ensuring a thorough cleaning.

[0034] After all cleaning processes are completed, the quality inspection stage begins. First, a liquid particle testing instrument is used to test the ultrasonic excitation of particles and the filtration circulation treatment. Ultrasonic waves with a frequency of 80 to 120 kHz are applied to the test solution to excite particles adsorbed on the component surface. Then, the test solution is circulated and filtered using a 0.1-micron pore size filter membrane. The particle concentration of the filtered solution is analyzed using a laser particle counter, with a detection limit of 0.05 microns. The particle concentration report is based on the number of particles per square centimeter of surface area. The acceptable standard is no more than 5 particles larger than 0.1 microns per square centimeter of surface area.

[0035] After passing inspection, the components are dried using high-purity nitrogen gas with a purity of no less than 99.999% and a dew point temperature below -70 degrees Celsius. Once the surface is completely dry, the components are placed in a cleanroom oven for further drying. The oven maintains an air cleanliness level of Class 5 as specified in ISO 14644-1, with vertical laminar airflow and a wind speed controlled between 0.3 and 0.5 meters per second. The drying temperature range is 80 to 100 degrees Celsius, and the drying time is strictly controlled to 2 hours. This drying process not only removes surface-adsorbed water, but the hot air convection also promotes the condensation of hydroxyl groups on the coating surface, enhancing the density and chemical stability of the alumina coating.

[0036] After drying, the components undergo a visual inspection, examining the surface for scratches, discoloration, and other defects under 1000 lux illumination. A final quality control check is then performed, re-verifying the component's appearance. Subsequently, the component surface is inspected using a 365 nm ultraviolet lamp in a darkroom environment. The background fluorescence intensity of the nano-alumina coating at this wavelength is below 10 photons per second per square centimeter. If a local fluorescence intensity exceeds this threshold, organic residue is identified, and the following steps must be repeated: Wipe the defective area three times unidirectionally with a non-woven fabric soaked in 99.7% isopropanol, with 10-second intervals between each wipe; then blow with 0.3 MPa compressed air at a 45° angle from 50 mm above the surface for 20 seconds. Repeat until the fluorescence intensity is below the threshold.

[0037] The particle level on the component surface was detected using a QIII particle detector with a sensitivity of 0.05 micrometers and a scanning speed of 100 square centimeters per second. Finally, qualified components were vacuum-sealed in double-layer polyethylene bags, with an inner bag thickness of 0.1 mm and an outer bag thickness of 0.15 mm. The vacuum level was maintained below -0.08 MPa to ensure no contamination during transportation and storage.

[0038] Example 2

[0039] In the cleaning of high-precision sensor components with nano-alumina coatings in the aerospace field, the cleaning process parameters were adjusted to meet the specific requirements of coating thicknesses of only 50 to 100 nanometers. Dry ice blasting pressure was reduced to 25 to 30 psi, dry ice particle size was controlled between 0.5 and 1 mm, and the blasting distance was increased to 250 to 300 mm to ensure effective removal of contaminants without damaging the ultra-thin coating. In the chemical cleaning stage, the contact time of the mixed acid solution was shortened to 3 to 5 minutes, the hydrofluoric acid concentration was reduced to 0.5% to 1%, and the nitric acid concentration was maintained at 2% to 3%, further reducing the risk of etching the coating.

[0040] The ultrasonic cleaning stage employs a segmented power control strategy: a low power density of 4 watts per square inch is used for the initial 10 minutes, increasing to 6 watts per square inch for the next 10 minutes, and then returning to 4 watts per square inch for the final 10 minutes. This power adjustment method ensures cleaning effectiveness while preventing damage to the ultra-thin coating caused by prolonged high-power ultrasound. The quality inspection stage includes a surface roughness measurement step, using a white light interferometer to measure the change in surface roughness before and after cleaning, ensuring that the Ra value change does not exceed 0.5 nanometers.

[0041] The drying process employs a stepped temperature increase method: the temperature is maintained at 80 degrees Celsius for the first 30 minutes, then increased to 90 degrees Celsius for the next 30 minutes, and finally held at 100 degrees Celsius for the last 60 minutes. This temperature control strategy facilitates the slow evaporation of moisture within the coating, preventing micro-cracks caused by rapid drying. During the packaging stage, high-purity nitrogen is filled into vacuum polyethylene bags to create a protective atmosphere, further preventing oxidation risks during transportation.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components, characterized in that, The method includes the following steps: The nano-alumina coated parts were immersed in isopropanol at room temperature for 30 minutes. The surface of the parts after isopropanol immersion was then rinsed with running pure water for at least 2 minutes. Next, the parts were immersed in hot water at 45-60 degrees Celsius for 30 minutes. The surface was then rinsed again with running pure water for at least 2 minutes. The surface was then sandblasted using a carbon dioxide dry ice blasting device at a pressure of 25-45 psi. The sandblasted surface was then dried using compressed air. A mixed acid solution consisting of 2%-5% nitric acid, 0.5%-2% hydrofluoric acid, and the remainder pure water was prepared for chemical cleaning to remove microscopic deposits on the surface. Finally, the parts were immersed three times in a pure water bath to remove any residual acid. The pressure used was... A thorough rinse of the component surface is performed using an 800-1000 psi high-pressure water gun, including all small holes and both sides, for at least 2 minutes. The component is then cleaned with a 2%-5% nitric acid solution to form a protective oxide film on the surface. The component is then immersed three times in a pure water bath to remove any residual nitric acid. The high-pressure water rinsing process is repeated, using an 800-1000 psi high-pressure water gun to rinse the component surface for at least 2 minutes. Finally, the component is placed in a pure water ultrasonic cleaning bath for cleaning, with the ultrasonic power density... The ultrasonic cleaning process involves several steps: First, the ultrasonic power density is 4 to 8 watts per square inch, and the operation time is 20 to 30 minutes. Then, the components are dried using filtered compressed air until no water is visible on the surface. Next, the components are rinsed with running pure water for at least 2 minutes. Then, a second ultrasonic cleaning with pure water is performed at a power density of 4 to 8 watts per square inch for 20 to 30 minutes. Finally, the components are rinsed with running pure water for at least 2 minutes. A liquid particle tester is used to test the ultrasonic excitation and filtration cycle treatment of the components, checking the overall particle level on all surfaces. The components are then dried using high-purity nitrogen until no water is visible on the surface. The components are then dried in a cleanroom oven at a temperature of 80 to 100 degrees Celsius for 2 hours. After drying, the components undergo a visual inspection. A final quality control check is performed, verifying the appearance of the components. The surface of the components is inspected using a UV lamp to ensure there are no fluorescent defects. The particle level on the surface of the components is checked using a QIII particle detector. Finally, qualified components are sealed in double-layer vacuum polyethylene bags.

2. The dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components according to claim 1, characterized in that, In the isopropanol immersion treatment, the purity of isopropanol is not less than 99.7%, and the immersion process is carried out in a sealed container.

3. The dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components according to claim 1, characterized in that, During the hot water immersion treatment, the water temperature is maintained within the range of 45 to 60 degrees Celsius. The hot water is ultrapure water that has undergone ion exchange and reverse osmosis treatment, and its resistivity is not less than 18 megohm-cm.

4. The dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components according to claim 1, characterized in that, In the carbon dioxide dry ice sandblasting process, the dry ice particle size is distributed between 0.5 and 3 mm, the sandblasting distance is controlled between 100 and 300 mm, and the sandblasting angle is at an angle of 15 to 45 degrees relative to the normal of the component surface.

5. The dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components according to claim 1, characterized in that, The nitric acid concentration of the mixed acid solution is preferably 3%, the hydrofluoric acid concentration is preferably 1%, the reaction time of the mixed acid solution is controlled at 5 to 10 minutes, and the operating temperature is maintained at 20 to 25 degrees Celsius.

6. The dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components according to claim 1, characterized in that, In the high-pressure water washing operation, the water jet pressure is set to 900 psi, and the water jet nozzle adopts a fan-shaped wide-angle design with a coverage angle of 60 to 80 degrees.

7. The dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components according to claim 1, characterized in that, In the ultrasonic cleaning process, the ultrasonic frequency is set to 40 kHz, and the product of the ultrasonic power density and the action time is controlled within the range of 160 to 240 watts per minute per square inch.

8. The dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components according to claim 1, characterized in that, In the liquid particle test, the test principle is to apply ultrasonic waves with a frequency of 80 to 120 kHz to the test liquid to excite the particles adsorbed on the surface of the component. Then, the test liquid is circulated and filtered using a filter membrane with a pore size of 0.1 micrometers, and the particle concentration of the filtered liquid is analyzed by a laser particle counter.

9. The dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components according to claim 1, characterized in that, In the aforementioned dust-free drying oven, the air cleanliness level inside the oven is Class 5 as specified in ISO 14644-1, the airflow organization is vertical laminar flow, and the wind speed is 0.3 to 0.5 meters per second.

10. The dry ice blasting-chemical dissolution-ultrasonic synergistic cleaning process for nano-alumina coated components according to claim 1, characterized in that, In the ultraviolet detection, an ultraviolet light source with a wavelength of 365 nanometers is used to irradiate the surface of the component in a dark room environment.

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