Acid and alkali corrosion resistant alloy material as well as preparation method and product thereof

Abstract

The invention discloses an acid and alkali corrosion resistant alloy material as well as a preparation method and a product thereof. The alloy material consists of 20.5 to 21.0 weight percent of Cr, 6.0 to 6.5 weight percent of Mo, 17.5 to 18.5 weight percent of Ni, 0.18 to 0.22 weight percent of N, 0.8 to 1.2 weight percent of Cu, 0.05 to 0.1 weight percent of Ce, less than or equal to 0.02 weight percent of C and the balance of Fe and inevitable impurities. According to the precise ball screw supporting bearing, through multi-azimuth collaborative design, the core requirements of excellent corrosion resistance, high strength and long service life under the working conditions of strong acid / alkali and high stress are met, and the precise ball screw supporting bearing is particularly suitable for semiconductor cleaning equipment and other severe environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy materials, and in particular relates to an alloy material resistant to acid and alkali corrosion, a preparation method thereof, and a product thereof. Background Art

[0002] The bearings in semiconductor cleaning equipment need to be acid-resistant and alkali-resistant, mainly based on the following core reasons: Highly corrosive chemical solutions are often used in the semiconductor cleaning process, and the bearings may directly or indirectly contact the following media: hydrofluoric acid, sulfuric acid, hydrochloric acid, etc., used to remove oxides and metal contaminants; ammonia water, SC1 solution, used to remove organic residues and particles, hydrogen peroxide, ozone water, etc., used for photoresist stripping and surface activation.

[0003] If the bearing material is not corrosion-resistant, chemical corrosion will occur. For example, stainless steel bearings will generate iron fluoride in HF, which will cause pitting corrosion and produce metal ion contamination (Fe 3+ Cr 3+ The metal particles or oxide flakes (such as Fe2O3) produced by bearing corrosion can adhere to the wafer surface with the cleaning fluid, causing circuit shorts and dielectric layer defects.

[0004] In the prior art, commonly used corrosion-resistant bearing materials include ceramic bearings: resistant to all acids and alkalis except HF, but with high cost; Hastelloy C-276 is resistant to HF, but with high price.

[0005] Chinese patent application number 201510525667.8 discloses an acid- and alkali-resistant alloy steel composed of the following components by weight: carbon 0.15-0.27%, silicon 0.25-0.46%, boron 0.12-0.18%, aluminum 0.05-0.14%, titanium 0.16-0.22%, cobalt 0.04-0.09%, antimony 0.5-1.2%, chromium 0.6-1.8%, zinc 0.4-1.3%, copper 0.05-0.8%, composite rare earth elements 0.04-0.1%, phosphorus <0.03%, sulfur <0.03%, and the balance iron. The alloy steel has significantly improved acid- and alkali-resistant performance, exceeding that of conventional alloy steel by more than five times, is less brittle, and has relatively low production costs.

[0006] The Chinese patent application number 2024103636584.2 discloses a stainless steel for fuel cell plates and a surface modification method thereof. The elemental composition of the stainless steel includes Cr: 20-30%, Ni: 0-20%, Mo: 3-10%, N: 0.05-1.5%, C: 0-0.03%, Si: 0-0.6%, Mn: 0-0.5%, Nb: 0-0.5%, W: 0-0.2%, Sn: 0-1%, Au: 0-0.5%, Ta: 0-0.5%, Al: 0-0.02%, Cu: 0-0.2%, P: 0-0.05%, S: 0-0.05%, Ce: 0-0.1%, and Fe makes up the balance. The surface passivation film and impurities of the stainless steel are removed and a new passivation film is generated. The self-corrosion current density can be less than 1μA / cm 2 , and also has excellent electrical conductivity, but the material has only been tested for corrosion resistance under acidic conditions, and it is not certain whether it can meet the application scenarios that require both acid and alkali resistance. Summary of the Invention

[0007] In order to overcome the deficiencies in the prior art, the present invention proposes a new type of acid- and alkali-resistant bearing alloy material that can be used to make semiconductor cleaning equipment. The specific technical solution of the present invention is as follows: The first technical solution of the present invention is: An acid and alkali corrosion-resistant alloy material consists of 20.5-21.0wt% Cr, 6.0-6.5wt% Mo, 17.5-18.5wt% Ni, 0.18-0.22wt% N, 0.8-1.2wt% Cu, 0.05-0.1wt% Ce, ≤0.02wt% C, the remainder Fe and inevitable impurities, wherein the O content in the Fe is ≤500ppm.

[0008] An acid and alkali corrosion-resistant alloy material for a ball screw support bearing consists of 20.5-21.0wt% Cr, 6.0-6.5wt% Mo, 17.5-18.5wt% Ni, 0.18-0.22wt% N, 0.8-1.2wt% Cu, 0.05-0.1wt% Ce, ≤0.02wt% C and the balance Fe, wherein O in the Fe is ≤500ppm.

[0009] Furthermore, the alloy material contains Mo+Cu at least 7wt% and a Cr / Ni mass ratio of 1.1-1.2. The key to this Mo+Cu 7wt% ratio is leveraging the Mo-Cu synergistic effect to enhance the repairability and density of the passive film. A Cr / Ni ratio of 1.1-1.2 optimizes the oxide film's chemical composition (NiCr2O4 spinel phase) and phase stability, achieving comprehensive corrosion resistance.

[0010] Furthermore, the pitting corrosion equivalent of the alloy material is 43.18–45.97, which is calculated based on the formula: pitting corrosion equivalent = %Cr + 3.3 × %Mo + 16 × %N.

[0011] Furthermore, the grain grade of the alloy material is ASTM grade 9-10.

[0012] A method for preparing the aforementioned acid- and alkali-resistant alloy material comprises the following steps: Step 1: Charge a furnace with 18.3-19.2wt% Cr, 6.0-6.5wt% Mo, 17.5-18.5wt% Ni, 0.8-1.2wt% Cu, 0.05-0.1wt% Ce, ≤0.02wt% C, and 51.5-54.2wt% Fe; Step 2: Evacuate the furnace to a vacuum state with a pressure value of ≤5×10 -3 pa; Step 3: Heat the raw materials to melt, preheat at 600℃ for 20 minutes, and then melt at 1520±10℃. The melting time should be ≤30min to avoid burning of Cr or Mo. Step 4: Add 2.8-3.4wt% FeCrN and stir for 12-15 minutes. Maintain the furnace temperature at 1550±10℃. Use a nitrogen-argon mixture (90% Ar + 10% N2) for environmental control. Blow argon from the bottom to stir the melt and promote the dissolution of FeCrN. Maintain a slight positive pressure of 0.1MPa in the furnace to avoid nitrogen loss. Preferably, FeCrN is FeCrN-6.5. FeCrN can be added in two batches. The first batch is 60% of the total amount. The remaining FeCrN is added after an interval of 2-3 minutes to ensure uniform melting. Step 5: Casting the electrode rod.

[0013] Furthermore, all raw materials from step 1 were sandblasted, ultrasonically cleaned with alcohol for 10 minutes, and then dried at 80°C for 2 hours. The furnace loading order was: first add the refractory metals (Mo, Fe), then the fusible metals (Ni, Cu, Cr), and finally add Ce wrapped in foil.

[0014] Step 2: Evacuate the furnace to a vacuum state with a pressure value of ≤5×10 -3 The procedure for pa is as follows: first, the mechanical pump is pre-pumped to ≤10Pa; then, the diffusion pump is switched and the temperature is raised to the working temperature and then pumped to ≤5×10 -3 Pa; finally, pressure maintenance test: leakage rate ≤ 0.02Pa / min. Equipment requirements: oil diffusion pump + cold trap, equipped with an ionization vacuum gauge to monitor vacuum degree.

[0015] Step 5: Casting the electrode rod. Casting conditions: mold preheating: preheat the graphite mold to 600°C to reduce thermal stress; casting temperature: 1550±5°C; speed: inclined casting (30° angle), flow rate 2-3 kg / s; cooling parameters: argon protection cooling to 800°C, cooling rate 50°C / s. Rapid cooling is used here to refine the grains, reduce segregation, and improve strength; subsequent air cooling to room temperature. The obtained electrode specifications are: Φ80×500mm, and the surface is turned (Ra≤3.2μm).

[0016] In order to further reduce the surface activity of the alloy material and improve the corrosion resistance, the present invention also provides a second technical solution, an acid and alkali corrosion resistant alloy material, which is composed of 20.5-21.0wt% Cr, 6.0-6.5wt% Mo, 17.5-18.5wt% Ni, 0.18-0.22wt% N, 0.8-1.2wt% Cu, 0.05-0.1wt% Ce, ≤0.02wt% C and the remainder of Fe and inevitable impurities. The surface of the alloy material contains a passivation layer, which is obtained by passivating the alloy material. The passivation solution uses 10% citric acid + 10% hydrogen peroxide + 0.05% cerium chloride + 1% sodium molybdate. The passivation process is: first, keep the film at 60°C for 30 minutes, then keep it at 40°C for 20 minutes, and after passivation is completed, neutralize and wash with water and then dry under nitrogen protection at 80°C. The main body of the passivation layer obtained by passivation treatment is a three-layer structure. The outermost layer is the surface organic layer, which is mainly a citric acid-Cr complex and acts as a hydrophobic barrier; the middle transition layer is CrOOH+Fe2O3+ Ni(OH)2, which buffers stress and inhibits interface peeling; the doped oxide layer, Cr2O3+MoO2+CeO2, is the main anti-corrosion layer, which blocks ion penetration.

[0017] Furthermore, the content of Mo+Cu in the alloy material is ≥7wt%, and the mass ratio of Cr / Ni is 1.1-1.2.

[0018] Furthermore, the pitting corrosion equivalent of the alloy material is 43.18–45.97.

[0019] Furthermore, the grain grade of the alloy material is ASTM grade 9-10.

[0020] The preparation method of the acid-alkali corrosion-resistant alloy material containing a passivation layer in this scheme is: Step 1: Charge a furnace with 18.3-19.2wt% Cr, 6.0-6.5wt% Mo, 17.5-18.5wt% Ni, 0.8-1.2wt% Cu, 0.05-0.1wt% Ce, ≤0.02wt% C, and 51.5-54.2wt% Fe; Step 2: Evacuate the furnace to a vacuum state with a pressure value of ≤5×10 -3 pa; Step 3: Heat the raw materials to melt, preheat at 600℃ for 20 minutes, and then melt at 1520±10℃. The melting time should be ≤30min to avoid burning of Cr or Mo. Step 4: Add 2.8-3.4wt% FeCrN and stir for 12-15 minutes. Maintain the furnace temperature at 1550±10℃. Use a nitrogen-argon mixture (90% Ar + 10% N2) for environmental control. Blow argon from the bottom to stir the melt and promote the dissolution of FeCrN. Maintain a slight positive pressure of 0.1MPa in the furnace to avoid nitrogen loss. Preferably, FeCrN is FeCrN-6.5. FeCrN can be added in two batches. The first batch is 60% of the total amount. The remaining FeCrN is added after an interval of 2-3 minutes to ensure uniform melting. Step 5: Casting electrode rods; Step 6: After machining and surface treatment, the electrode rods are passivated using a passivation solution consisting of 10% citric acid, 10% hydrogen peroxide, 0.05% cerium chloride, and 1% sodium molybdate. Specifically, the solution contains 10% citric acid, 10% hydrogen peroxide, 0.05% cerium chloride, and 1% sodium molybdate, all in water. The passivation process involves first forming a film at 60°C for 30 minutes, followed by curing the hydrophobic layer at 40°C for 20 minutes. After passivation, the electrodes are neutralized, rinsed with water, and dried at 80°C under a nitrogen atmosphere.

[0021] Preferably, 0.1 wt% of sodium citrate, a pH stabilizer, can be added to the passivation solution. Furthermore, 0.1-0.5 wt% of graphene or PTFE nanoparticles can be added to the passivation solution. Introducing graphene or PTFE nanoparticles into the organic layer can improve wear resistance and extreme pH stability.

[0022] Furthermore, all raw materials from step 1 were sandblasted, ultrasonically cleaned with alcohol for 10 minutes, and then dried at 80°C for 2 hours. The furnace loading order was: first add the refractory metals (Mo, Fe), then the fusible metals (Ni, Cu, Cr), and finally add Ce wrapped in foil.

[0023] Step 2: Evacuate the furnace to a vacuum state with a pressure value of ≤5×10 -3 The procedure for pa is as follows: first, the mechanical pump is pre-pumped to ≤10Pa; then, the diffusion pump is switched and the temperature is raised to the working temperature and then pumped to ≤5×10 -3 Pa; finally, pressure maintenance test: leakage rate ≤ 0.02Pa / min. Equipment requirements: oil diffusion pump + cold trap, equipped with an ionization vacuum gauge to monitor vacuum degree.

[0024] Step 5: Casting the electrode rod. Casting conditions: mold preheating: preheat the graphite mold to 600°C to reduce thermal stress; casting temperature: 1550±5°C; speed: inclined casting (30°C angle), flow rate 2-3 kg / s; cooling parameters: argon protection cooling to 800°C, cooling rate 50°C / s, subsequent air cooling to room temperature, preferably, 800°C-400°C, cooling rate 20°C / s, air cooling below 400°C, the final electrode specifications: Φ80×500mm, surface turning (Ra≤3.2μm).

[0025] The passivation layer on the surface of the passivated alloy material has a three-layer structure. The outermost layer is the surface organic layer, which is mainly composed of citric acid-Cr complex and acts as a hydrophobic barrier; the intermediate transition layer is CrOOH+Fe2O3+ Ni(OH)2, which buffers stress and inhibits interface peeling; the doped oxide layer is Cr2O3 + MoO2 + CeO2, which is the main anti-corrosion layer and blocks ion penetration.

[0026] The applicant believes that the passivation process may form a multilayer structure through the following mechanisms: First, the organic layer is mainly a citric acid-Cr complex. The citric acid (weakly acidic) in the passivation solution acts as an excellent chelating agent. The multiple carboxyl groups and hydroxyl groups on the citric acid molecules will quickly react with the metal atoms with the strongest surface activity (mainly Cr) to form a citric acid-Cr complex adsorption layer. Under the oxidation action of H2O2 at 60°C, the complex may undergo partial decarboxylation and / or oxidative polymerization to form an ultra-thin, cross-linked organic polymer network film; second, the transition layer. In the weakly acidic environment provided by citric acid, the Fe and Ni elements with higher electrochemical activity on the alloy surface will selectively dissolve in the microscopic anode area, with Fe 2+ 、Ni 2+ ions into the solution boundary layer close to the alloy surface. This process is in dynamic competition with the subsequent passivation formation and does not occur after the formation of the dense inner layer, but in the initial stage of film formation. - Ion generation (core mechanism): This is the key to the formation of the hydroxide intermediate layer and one of the most sophisticated chemical principles in this process design. - Mainly from H2O2 in Ce 3+ / Ce 4+ Decomposition under catalytic cycle, Ce in solution 3+ Fenton-like reaction with H2O2: H2O2+Ce 3+ → Ce 4 + OH + OH - This catalytic cycle continuously produces highly active OH radicals and high concentrations of OH near the alloy surface. -ions, resulting in a significant increase in local pH. 2+ 、Ni 2+ and a small amount of dissolved Cr 3+ ions, the high concentration of OH produced in the above reaction - Under the action of 2+ +2OH - → Fe(OH)2 (subsequently oxidized by H2O2 to more stable Fe2O3), Ni 2+ +2OH - → Ni(OH)2, Cr 3+ +3OH - → Cr(OH)3 (partially dehydrated to form CrOOH). These newly generated hydroxide / oxide nanoparticles undergo heterogeneous nucleation and growth below the formed organic complex layer or in its micropores, intercalating to form a mixed, dense intermediate transition layer. Finally, a doped oxide layer forms, and the large amount of Cr and Mo elements in the alloy matrix undergo in-situ oxidation directly at the metal / film interface under the strong oxidizing effect of H2O2. The presence of Mo can significantly promote the passivation of Cr, and the MoO4 provided by sodium molybdate 2- The ions are reduced and doped into the Cr2O3 lattice in the form of molybdenum oxide, forming a more stable Cr-Mo composite oxide layer (Cr2O3+MoO2). In the formation of the transition layer, H2O2+Ce 3+ Ce generated by the reaction 4+ The ions are extremely unstable and will quickly hydrolyze and deposit into ultrafine CeO2 nanoparticles. 4+ +2H2O →CeO2(s)+4H + These CeO2 nanoparticles will fill the grain boundaries, pores and other defects of the growing Cr-Mo oxide layer, playing a "physical pinning" and "filling" role, greatly improving the density and resistance to ion penetration of the layer. 3+ / Ce 4+ The presence of the redox couple endows the passivation film with a certain degree of chemical repair capability in the event of local damage. Through the sequential reaction of the three stages described above, a functionally gradient composite film is ultimately formed on the alloy surface. The outer organic layer provides a hydrophobic barrier, isolating most aqueous media. The intermediate transition layer, due to its flexible hydroxide phase and the volume differences between different oxides, acts as a stress buffer and inhibits interlayer delamination. The innermost Cr-Mo-Ce ternary composite oxide layer serves as the core anti-corrosion barrier, blocking the penetration of corrosive ions.

[0027] The present invention also provides a third technical solution. When the alloy material is used to make high-load components such as bearings, on the basis of the alloy described in the second technical solution, the alloy material further adds a layer of Ce-O modified passivation film on the surface of the passivation layer. The preparation method is based on the preparation method in the second technical solution of the present invention and also includes step 7: sealing treatment, soaking in 0.05% Ce(NO3)3 melt at 80°C for 20-30 minutes to form a Ce-O modified passivation film on the surface of the passivation layer, thereby obtaining an acid and alkali corrosion-resistant alloy material for ball screw support bearings, which is composed of 20.5-21.0wt% Cr, 6.0-6.5wt% Mo, 17.5-18.5wt% Ni, 0.18-0.22wt% N, 0.8-1.2wt% Cu, 0.05-0.1wt% Ce, ≤0.02wt% C and the remainder of Fe and inevitable impurities, and the surface of the alloy material has a Ce-O modified passivation film.

[0028] A product made of the aforementioned acid- and alkali-resistant alloy material is a bearing, which can be a ball screw support bearing. Specifically, the alloy rod is formed by cold heading or hot forging, then rough grinding, quenching, and then fine grinding, polishing, and testing.

[0029] The functions of the alloy raw materials in the present invention are as follows: Cr is a core element that forms a dense Cr2O3 passivation film, providing fundamental corrosion resistance. Especially in acidic environments, a high Cr content (>20%) can significantly improve pitting resistance. In some embodiments, the Cr content can be 20.5wt%, 20.7wt%, 20.9wt%, or 21wt%, or any value in between.

[0030] Mo (6.0-6.5 wt%) enhances resistance to localized corrosion (pitting and crevice corrosion) and synergistically improves the PREN value with Cr / N. In some embodiments, the Mo content can be 6.0 wt%, 6.1 wt%, 6.2 wt%, 6.3 wt%, 6.4 wt%, or 6.5 wt%, or any value between these two values.

[0031] Ni (17.5-18.5 wt%): Stabilizes the austenite phase, preventing transformation to martensite during cold working or welding, maintaining toughness, and improving resistance to reducing acids (such as dilute sulfuric acid). In some embodiments, the Ni content can be 17.5 wt%, 17.8 wt%, 18 wt%, 18.2 wt%, or 18.5 wt%, or any value in between.

[0032] N (0.18-0.22wt%): The nitrogen in the technical solution of this application is added to the melt in the form of FeCrN at 1550±10℃ under argon protection. By precisely controlling the holding time, efficient solid solution of 0.18-0.22 wt% nitrogen is achieved. This method takes into account the triple requirements of semiconductor materials for composition accuracy, corrosion resistance, and toughness. Its solid solution strengthening contribution exceeds 400 MPa. At the same time, the grain boundary stabilization effect of nitrogen increases the life of the bearing in acidic and alkaline environments by more than 3 times. In some embodiments, the N content can be 0.18wt%, 0.2wt%, or 0.22wt%, or any value between these two values.

[0033] Cu (0.8-1.2 wt%): Improves resistance to sulfuric acid and phosphoric acid corrosion and promotes repair of the passivation film. In some embodiments, the Cu content can be 0.8 wt%, 1 wt%, or 1.2 wt%, or any value between these two values.

[0034] Ce (0.05-0.1 wt%): Rare earth elements refine grains, purify grain boundaries (sulfide inclusion modification), and improve high-temperature oxidation resistance. In some embodiments, the Ce content can be 0.05 wt%, 0.08 wt%, or 0.1 wt%, or any value in between.

[0035] Ultra-low carbon (≤0.02wt% C): Avoids the formation of carbides between carbon and Cr, preventing intergranular corrosion sensitization.

[0036] The combination of Cu (resistance to sulfuric acid corrosion) and Ce (refines grains and promotes passive film repair) fills the gap in bearing materials in acidic environments; ultra-low C (≤0.02%) + controlled N: while avoiding intergranular corrosion, the strength loss caused by the lack of C is compensated by N solid solution strengthening.

[0037] The alloy of the present invention is strengthened by the Cr / Mo / Ni passivation film, Mo+Cu resists reducing acid, Ce purifies the grain boundary, and the elements synergistically achieve corrosion resistance in all acid and alkali environments; Cr+Mo+N synergistically inhibits local corrosion, optimizes the pitting equivalent, and meets the stability in high chloride ion environments; the surface hydrophobic layer in the passivation layer solves the problem of insufficient hydrophobicity of traditional passivation films, the transition layer (buffers stress through hydroxides to inhibit film peeling, and the main anti-corrosion layer uses the oxygen vacancy repair ability of CeO2 + the Cl - Adsorption inhibition, forming a "self-repairing" barrier.

[0038] Through multi-faceted collaborative design, this application achieves the core requirements of excellent corrosion resistance, high strength and long life under strong acid / alkali and high stress conditions. It is particularly suitable for precision ball screw support bearings in harsh environments such as semiconductor cleaning equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1This is a metallographic diagram of the alloy prepared in Example 1 of the present invention; Figure 2 This is a metallographic diagram of the alloy prepared in Example 2 of the present invention; Figure 3 This is a metallographic diagram of the alloy prepared in Example 3 of the present invention; Figure 4 This is a design diagram for the cycle test of the present invention; Figure 5 This is a photo of the ball screw support bearing produced in Example 5 of the present invention. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0041] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the specified features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0042] In the description of the present invention, the term "for example" is used to mean "used as an example, illustration or illustration". Any embodiment of the present invention described as "for example" is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is given to enable any person skilled in the art to implement and use the present invention. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present invention can be implemented without using these specific details. In other examples, well-known structures and processes are not elaborated in detail to avoid obscuring the description of the present invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed herein.

[0043] Example 1 The alloy material resistant to acid and alkali corrosion is prepared according to the following method steps: Step 1: Charge 20.5wt% Cr, 6.5wt% Mo, 17.5wt% Ni, 1wt% Cu, 0.05wt% Ce, ≤0.02wt% C, and 54.5wt% Fe into a furnace. The order of charging is: first charge refractory metals (Mo, Fe), then charge fusible metals (Ni, Cu, Cr), and finally add Ce wrapped in foil. Specifically, all raw materials must be sandblasted, ultrasonically cleaned with alcohol for 10 minutes, and then dried at 80°C for 2 hours. Step 2: Evacuate the furnace to a vacuum state with a pressure value of ≤5×10 -3 The operation procedure is as follows: 1. Pre-pump with a mechanical pump to ≤10 Pa; 2. Switch to a diffusion pump, heat it to the operating temperature, and then pump it to ≤5×10 -3 Pa (about 30 minutes); 3. Pressure maintenance test: leakage rate ≤ 0.02 Pa / min; Step 3: Heat to melt the raw materials, preheat at 600℃ for 20 minutes, and then melt at 1520℃; Step 4: Casting the electrode rod. Casting conditions: mold preheating: preheat the graphite mold to 600°C to reduce thermal stress; casting temperature: 1550±5°C; speed: inclined casting (30° angle), flow rate 2-3 kg / s; cooling parameters: argon protection cooling to 800°C, cooling rate 50°C / s, and subsequent air cooling to room temperature. The final electrode specifications are: Φ80×500mm, surface turning (Ra≤3.2μm).

[0044] The alloy rod structure prepared in this embodiment is referenced Figure 1 The grain size is evaluated as about level 9 according to ASTM E112 "Standard Test Method for Determining Average Grain Size". The grains are very fine. The measured corrosion resistance is shown in Table 1.

[0045] Example 2 Acid and alkali corrosion resistant alloy material is prepared according to the following method and steps: Step 1: Charge the furnace with 21wt% Cr, 6.5wt% Mo, 18.5wt% Ni, 1.1wt% Cu, 0.08wt% Ce, ≤0.02wt% C, and 52.8wt% Fe. The order of charging is as follows: first charge the refractory metals (Mo, Fe), then charge the fusible metals (Ni, Cu, Cr), and finally add Ce wrapped in foil. All raw materials need to be sandblasted, ultrasonically cleaned with alcohol for 10 minutes, and then dried at 80°C for 2 hours. Step 2: Evacuate the furnace to a vacuum state with a pressure value of ≤5×10 -3 The operation procedure is as follows: 1. Pre-pump with a mechanical pump to ≤10 Pa; 2. Switch to a diffusion pump, heat it to the operating temperature, and then pump it to ≤5×10 -3Pa (about 30 minutes); 3. Pressure maintenance test: leakage rate ≤ 0.02 Pa / min; Step 3: Heat to melt the raw materials, preheat at 600℃ for 20 minutes, and then melt at 1510℃; Step 4: Casting the electrode rod. Casting conditions: mold preheating: graphite mold preheated to 600℃ to reduce thermal stress; casting temperature: 1550±5℃; speed: inclined casting (30° angle), flow rate 2-3 kg / s; cooling parameters: argon protection cooling to 800℃, cooling rate 50℃ / s, followed by air cooling to room temperature. The final electrode specifications are: Φ80×500mm, surface turning (Ra≤3.2μm); Step 5: After machining and surface treatment, the electrode rod is passivated using a passivation solution of 10% citric acid, 10% hydrogen peroxide, 0.05% cerium chloride, and 1% sodium molybdate. The passivation process involves first forming a film at 60°C for 30 minutes, then curing the hydrophobic layer at 40°C for 20 minutes. After passivation, the electrode rod is neutralized, rinsed with water, and dried at 80°C under nitrogen. Preferably, 0.1 wt% of sodium citrate, a pH stabilizer, may also be added to the passivation solution.

[0046] The alloy rod structure prepared in this embodiment is referenced Figure 2 The grain size is evaluated according to ASTM E112 "Standard Test Method for Determining Average Grain Size" and is approximately level 9-10. The grains are uniform. The measured corrosion resistance is shown in Table 1.

[0047] Example 3 The alloy material for ball screw support bearings resistant to acid and alkali corrosion is prepared according to the following method and steps: Step 1: Charge the furnace with 18.3wt% Cr, 6.5wt% Mo, 17.5wt% Ni, 1wt% Cu, 0.05wt% Ce, ≤0.02wt% C, and 52.7wt% Fe. The order of charging is as follows: first charge the refractory metals (Mo, Fe), then charge the fusible metals (Ni, Cu, Cr), and finally add Ce wrapped in foil. All raw materials need to be sandblasted, ultrasonically cleaned with alcohol for 10 minutes, and then dried at 80°C for 2 hours. Step 2: Evacuate the furnace to a vacuum state with a pressure value of ≤5×10 -3 The operation procedure is as follows: 1. Pre-pump with a mechanical pump to ≤10 Pa; 2. Switch to a diffusion pump, heat it to the operating temperature, and then pump it to ≤5×10 -3 Pa (about 30 minutes); 3. Pressure maintenance test: leakage rate ≤ 0.02 Pa / min; Step 3: Heat to melt the raw materials, preheat at 600℃ for 20 minutes, and then melt at 1520℃; Step 4: Add 2.8wt% FeCrN and stir for 12-15 minutes. Maintain the furnace temperature at 1550±10°C. Use a nitrogen-argon mixture (90% Ar + 10% N2) for environmental control. Blow argon from the bottom to stir the melt and promote the dissolution of FeCrN. Maintain a slight positive pressure of 0.1MPa in the furnace to avoid nitrogen loss. Preferably, FeCrN is FeCrN-6.5. FeCrN can be added in two batches. The first batch is 60% of the total amount. The remaining FeCrN is added after an interval of 2-3 minutes to ensure uniform melting. Step 5: Casting the electrode rod. Casting conditions: mold preheating: preheat the graphite mold to 600°C to reduce thermal stress; casting temperature: 1550±5°C; speed: inclined casting (30° angle), flow rate 2-3 kg / s; cooling parameters: argon protection cooling to 800°C, cooling rate 50°C / min, and subsequent air cooling to room temperature. The final electrode specifications are: Φ80×500mm, and the surface is turned (Ra≤3.2μm).

[0048] The grain size of the alloy rod prepared in this example was evaluated to be approximately level 9-10 according to ASTM E112 "Standard Test Method for Determination of Average Grain Size". The grains were very fine and evenly distributed. The measured corrosion resistance is shown in Table 1.

[0049] Example 4 The alloy material for ball screw support bearings resistant to acid and alkali corrosion is prepared according to the following method and steps: Step 1: Charge the furnace with 18.7wt% Cr, 6.5wt% Mo, 18.5wt% Ni, 1.1wt% Cu, 0.08wt% Ce, ≤0.02wt% C, and 51.7wt% Fe. The order of charging is as follows: first charge the refractory metals (Mo and Fe), then the fusible metals (Ni, Cu, and Cr). Ce is wrapped in foil and added last. All raw materials are sandblasted, ultrasonically cleaned with alcohol for 10 minutes, and then dried at 80°C for 2 hours. Step 2: Evacuate the furnace to a vacuum state with a pressure value of ≤5×10 -3 pa, evacuate the furnace to a vacuum state, the pressure value is ≤5×10 -3 The procedure for pa is as follows: 1. Pre-pump with a mechanical pump to ≤10Pa; 2. Switch to a diffusion pump, heat it to the operating temperature, and then pump it to ≤5×10 -3 Pa (about 30 minutes); 3. Pressure maintenance test: leakage rate ≤ 0.02 Pa / min; Step 3: Heat to melt the raw materials, preheat at 600℃ for 20 minutes, and then melt at 1510℃; Step 4: Add 3.4wt% FeCrN and stir for 12-15 minutes. Maintain the furnace temperature at 1550±10℃. Use a nitrogen-argon mixture (90% Ar + 10% N2) for environmental control. Blow argon from the bottom to stir the melt and promote the dissolution of FeCrN. Maintain a slight positive pressure of 0.1MPa in the furnace to avoid nitrogen loss. Preferably, FeCrN-6.5 is used. FeCrN can be added in two batches. The first batch is 60% of the total amount. The remaining FeCrN is added after an interval of 2-3 minutes to ensure uniform melting. Step 5: Casting the electrode rod. Casting conditions: mold preheating: graphite mold preheated to 600℃ to reduce thermal stress; casting temperature: 1550±5℃; speed: inclined casting (30° angle), flow rate 2-3 kg / s; cooling parameters: argon protection cooling to 800℃, cooling rate 50℃ / min, followed by air cooling to room temperature. The final electrode specifications: Φ80×500mm, surface turning (Ra≤3.2μm); Step 6: After machining and surface treatment, the electrode rod is passivated using a passivation solution of 10% citric acid, 10% hydrogen peroxide, 0.05% cerium chloride, and 1% sodium molybdate. The passivation process involves first forming a film at 60°C for 30 minutes, then curing the hydrophobic layer at 40°C for 20 minutes. After passivation, the electrode rod is neutralized, rinsed, and dried at 80°C under nitrogen. Preferably, 0.1 wt% of sodium citrate, a pH stabilizer, may also be added to the passivation solution.

[0050] The alloy rod prepared in this example had a grain size of approximately 9-10, as assessed according to ASTM E112, "Standard Test Method for Average Grain Size," indicating uniform grain size. This indicates that the alloy rod treated using the method of this example has a uniform grain size, meeting standard requirements. The measured corrosion resistance is shown in Table 1.

[0051] Example 5 The alloy material for ball screw support bearings resistant to acid and alkali corrosion is prepared according to the following method and steps: Step 1: Charge the furnace with 19.2wt% Cr, 6.2wt% Mo, 18.5wt% Ni, 1.1wt% Cu, 0.1wt% Ce, ≤0.02wt% C, and 52.73wt% Fe. The order of charging is as follows: first charge the refractory metals (Mo and Fe), then the fusible metals (Ni, Cu, and Cr). Ce is wrapped in foil and added last. All raw materials are sandblasted, ultrasonically cleaned with alcohol for 10 minutes, and then dried at 80°C for 2 hours. Step 2: Evacuate the furnace to a vacuum state with a pressure value of ≤5×10 -3pa, the operating procedures are as follows: 1. Pre-pump with a mechanical pump to ≤10Pa; 2. Switch to a diffusion pump, heat it to the operating temperature, and then pump it to ≤5×10 -3 Pa (about 30 minutes); 3. Pressure maintenance test: leakage rate ≤ 0.02 Pa / min; Step 3: Heat to melt the raw materials, preheat at 600℃ for 20 minutes, and then melt at 1520℃; Step 4: Add 3.0wt% FeCrN and stir for 12-15 minutes. Maintain the furnace temperature at 1550±10℃. Use a nitrogen-argon mixture (90% Ar + 10% N2) for environmental control. Blow argon from the bottom to stir the melt and promote the dissolution of FeCrN. Maintain a slight positive pressure of 0.1MPa in the furnace to avoid nitrogen loss. Preferably, FeCrN is FeCrN-6.5. FeCrN can be added in two batches. The first batch is 60% of the total amount. The remaining FeCrN is added after an interval of 2-3 minutes to ensure uniform melting. Step 5: Casting the electrode rod. Casting conditions: mold preheating: graphite mold preheated to 600℃ to reduce thermal stress; casting temperature: 1550±5℃; speed: inclined casting (30° angle), flow rate 2-3 kg / s; cooling parameters: argon protection cooling to 800℃, cooling rate 50℃ / s, 800℃-400℃, cooling rate 20℃ / s, air cooling below 400℃. The final electrode specifications: Φ80×500mm, surface turning (Ra≤3.2μm); Step 6: After machining and surface treatment, the electrode rod is passivated using a passivation solution consisting of 10% citric acid, 10% hydrogen peroxide, 0.05% cerium chloride, and 1% sodium molybdate. The passivation process involves first forming a film at 60°C for 30 minutes, then curing the hydrophobic layer at 40°C for 20 minutes. After passivation, the electrode rod is neutralized and rinsed with water before drying at 80°C under nitrogen protection. Preferably, 0.1% sodium citrate, a pH stabilizer, may be added to the passivation solution. Step 7: Sealing treatment: soak in 0.05% Ce(NO3)3 solution at 80℃ for 20-30 minutes to form a Ce-O modified passivation film.

[0052] The alloy prepared in this embodiment has a grain size of about 9-10 according to ASTM E112 "Standard Test Method for Determining Average Grain Size", and the grains are uniform. It can be seen that the grain size of the alloy bar treated by the method of this embodiment is uniform and meets the standard requirements. The alloys prepared in Examples 1-5 were subjected to acid and alkali cycle tests. The test process is as follows: Figure 4 The test results are shown in Table 1: Table 1 Acid and alkali resistance cycle test results of the alloys prepared in Examples 1-5

[0053] The corrosion rate in Table 1 = , where K is the unit conversion constant equal to 8.76×10 4 , is the weight loss (g), ρ is the material density, A is the exposure area (Φ80×500mm), T is the test time, 500 cycles are performed in this application, and the test time is calculated as 1 year. The average annual corrosion rates of the alloy products prepared in Examples 1-5 of the present invention are 0.45µm / year, 0.43µm / year, 0.26µm / year, 0.19µm / year and 0.10µm / year, respectively. Compared with the SEMI7 standard, the bearing products prepared in Examples 1-5 can meet the general requirement of semiconductor equipment of <0.5µm / year, and the corrosion resistance of Examples 3-5 is even better.

[0054] Furthermore, the stability of the surface passivation films of Examples 4 and 5 was analyzed and tested by using standardized EIS experiment + equivalent circuit fitting to test the charge transfer resistance (R t ) and diffusion coefficient (n), and the test results are shown in Table 2.

[0055] Table 2 Performance of the passivation films of the products obtained in Examples 4 and 5

[0056] As shown in Table 2, the passivation films of the products prepared in Examples 4 and 5 are relatively complete and uniform.

[0057] The alloy prepared in Example 5 was made into a ball screw support bearing. The applicant found that the alloy material is suitable for making the outer ring, inner ring and rolling element of the ball screw support bearing, which can significantly improve the reliability and life of the ball screw support bearing under harsh working conditions. Figure 5 shown.

Claims

1. An acid and alkali corrosion resistant alloy material, characterized in that: The alloy material has a grain grade of 9-10 and is composed of 20.5-21.0wt% Cr, 6.0-6.5wt% Mo, 17.5-18.5wt% Ni, 0.18-0.22wt% N, 0.8-1.2wt% Cu, 0.05-0.1wt% Ce, ≤0.02wt% C and the remainder of Fe and inevitable impurities, wherein the content of Mo+Cu is ≥7wt%, and the mass ratio of Cr / Ni is 1.1-1.

2. The surface of the alloy material contains a passivation layer, which is obtained by passivating the alloy material. The passivation solution uses 10% citric acid + 10% hydrogen peroxide + 0.05% cerium chloride + 1% sodium molybdate. The passivation process is as follows: first, maintain the film at 60°C for 30 minutes, then maintain it at 40°C for 20 minutes, neutralize and wash it with water after the passivation is completed, and then dry it at 80°C under nitrogen protection.

2. The acid and alkali corrosion resistant alloy material according to claim 1, characterized in that: The pitting corrosion equivalent of this alloy material is 43.18–45.

97.

3. A method for preparing the acid- and alkali-resistant alloy material according to claim 1, characterized in that: The following steps are involved: Step 1: Charge a furnace with 18.3-19.2wt% Cr, 6.0-6.5wt% Mo, 17.5-18.5wt% Ni, 0.8-1.2wt% Cu, 0.05-0.1wt% Ce, ≤0.02wt% C, and 51.5-54.2wt% Fe; Step 2: Evacuate the furnace to a vacuum state with a pressure value of ≤5×10 -3 pa; Step 3: Heat to melt the raw materials, preheat at 600℃ for 20 minutes, and then melt at 1520±10℃; Step 4: Add 2.8-3.4wt% FeCrN, stir for 12-15 minutes, maintain the furnace temperature at 1550±10℃, use nitrogen and argon mixed gas protection, and maintain a slightly positive pressure; Step 5: Casting electrode rods; Step 6: After machining and surface treatment of the prepared electrode rod, passivation treatment is performed. The passivation solution is 10% citric acid + 10% hydrogen peroxide + 0.05% cerium chloride + 1% sodium molybdate. The passivation process is as follows: first, keep the film at 60°C for 30 minutes, then keep it at 40°C for 20 minutes. After passivation is completed, neutralize and wash with water, and then dry it at 80°C under nitrogen protection.

4. The method for preparing the acid- and alkali-resistant alloy material according to claim 3, wherein: It also includes step 7: sealing treatment, soaking in 0.05% Ce(NO3)3 melt at 80°C for 20-30 minutes.

5. A product made of the acid- and alkali-corrosion-resistant alloy material according to claim 1, which is a ball screw support bearing.

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