Yttrium sol and preparation method and application thereof

Abstract

The invention relates to the technical field of yttrium sol preparation, in particular to yttrium sol and a preparation method and application thereof. The preparation method of the yttrium sol provided by the invention comprises the following steps: adding yttrium salt into water, stirring and dissolving to obtain a solution A, and then adding glacial acetic acid into the solution A, stirring and dissolving to obtain a solution B; ethylene glycol is added into the solution B for a reaction, and yttrium sol is obtained; wherein the mass ratio of the yttrium salt to the glacial acetic acid to the ethylene glycol is (7-9): 1: 1. According to the invention, glacial acetic acid is used as a chelating agent and is matched with ethylene glycol to prepare the yttrium sol, so that the solid content and the stability of the yttrium sol can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of yttrium sol preparation, and in particular to a yttrium sol and a preparation method and application thereof. Background Art

[0002] With the increasing demand for research and preparation of advanced aero-engine materials, titanium-aluminum alloy (TiAl) has become an ideal material for advanced aero-engine manufacturing due to its high-temperature oxidation resistance, high strength, low density, and corrosion resistance. Investment casting is the most cost-effective method for producing complex TiAl alloy parts. However, existing investment casting shell materials (such as mullite and zircon powder) easily react with TiAl alloy at high temperatures, resulting in defects such as oxygen-rich layers and pores on the casting surface, which affect the performance of the casting.

[0003] Research has shown that yttrium oxide (Y2O3) exhibits excellent chemical stability at high temperatures and is resistant to reaction with titanium-aluminum alloys, making it an ideal material for investment casting shells. However, pure Y2O3 shells suffer from severe slagging and high cost. Yttrium sol, as a solvent and binder, can effectively improve the high-temperature resistance, oxidation resistance, and corrosion resistance of cast parts while remaining non-reactive with the substrate and other materials. However, existing commercially available yttrium sols have a low solids content (approximately 14%) and poor stability, making them difficult to meet the demands for high solids content and high stability.

[0004] Therefore, developing a method for preparing yttrium sol with high solid content, high stability, small and uniform particle size has important research significance and application value. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a yttrium sol and its preparation method and application. The present invention uses glacial acetic acid as a chelating agent and uses it in combination with ethylene glycol to prepare the yttrium sol, which can improve the solid content and stability of the yttrium sol.

[0006] To this end, the present invention provides the following technical solutions: In a first aspect, the present invention provides a method for preparing yttrium sol in an optional embodiment, comprising the following steps: Adding yttrium salt to water and stirring to dissolve to obtain solution A, then adding glacial acetic acid to the solution A and stirring to dissolve to obtain solution B; adding ethylene glycol to the solution B to react and obtain yttrium sol; Wherein, the mass ratio of the yttrium salt, glacial acetic acid and ethylene glycol is 7-9:1:1.

[0007] In the present invention, the carboxylate groups of glacial acetic acid provide oxygen atoms to coordinate with yttrium ions, while glacial acetic acid and ethylene glycol react to form esters. The esters form an organic network structure in the solvent and coordinate with the yttrium ions, slowing the hydrolysis of the yttrium ions. Furthermore, the organic network structure acts as a steric hindrance, preventing excessive aggregation of colloid particles and enhancing the stability of the sol.

[0008] Preferably, the mass ratio of the yttrium salt, glacial acetic acid and ethylene glycol is 8:1:1.

[0009] Preferably, the yttrium salt is selected from one or more of yttrium nitrate hexahydrate, yttrium chloride hexahydrate or yttrium sulfate.

[0010] Preferably, when preparing solution B, the temperature for stirring and dissolving is 20-30°C.

[0011] Preferably, the reaction time is 30-60 min; and / or the reaction temperature is 55-65°C.

[0012] In a second aspect, the present invention provides an yttrium sol in an optional embodiment, which is prepared using the above-mentioned preparation method.

[0013] Preferably, the solid content of the yttrium sol is ≥24%; and / or the particle size of the yttrium sol is 8-20 nm; and / or the Zeta potential of the yttrium sol is 20-30 mV.

[0014] In a third aspect, the present invention provides, in an optional embodiment, an application of the yttrium sol prepared by the above preparation method in investment casting.

[0015] In a fourth aspect, the present invention provides, in an optional embodiment, an application of the yttrium sol prepared by the above preparation method in a high-temperature anti-oxidation coating.

[0016] In a fifth aspect, the present invention provides, in an optional embodiment, an application of the yttrium sol prepared by the above preparation method in corrosion-resistant materials.

[0017] Compared with the prior art, the present invention has one of the following beneficial effects: 1. The present invention uses glacial acetic acid as a chelating agent and is used in combination with ethylene glycol to prepare yttrium sol, which can improve the solid content and stability of the yttrium sol.

[0018] 2. The preparation method of the present invention is simple, can save costs, and has great application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 Schematic diagram of the results of identification of the yttrium sol prepared in Example 1 of the present invention using an infrared laser with a wavelength of 790 nm; Figure 2 Schematic diagram of the XRD results of the product of the yttrium sol prepared in Example 1 of the present invention after calcination at 800°C; Figure 3 This is a physical picture of a mold shell obtained by sintering the yttrium sol prepared in Example 1 in an application example of the present invention; Figure 4 Schematic diagram of the process of measuring the porosity and bulk density of a mold shell using the Archimedes method in an application example of the present invention; Figure 5 This is a schematic diagram of the process of measuring the room temperature strength of a mold shell using three-point bending in an application embodiment of the present invention; Figure 6 This is a microscopic morphology image obtained by scanning electron microscopy observation of the shell obtained by sintering the yttrium sol prepared in Example 1 in the application example of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] The technical solution of the present invention will be described below with reference to embodiments.

[0023] Example 1 This embodiment provides a method for preparing yttrium sol, comprising the following steps: Weigh 40 g of yttrium nitrate hexahydrate (Y(NO3)3·6H2O) using a balance, add it to 20 ml of deionized water, and stir it on a magnetic stirrer for 1 hour to completely dissolve it, thereby obtaining solution A; add 5 g of glacial acetic acid to solution A, place it in a 30°C water bath, stir it to dissolve it, and mix it evenly to obtain a mixed solution B; add 5 g of ethylene glycol to solution B, place it in a 60°C water bath, and react for 45 minutes to obtain a yttrium sol.

[0024] Yttrium sol was identified by infrared laser at a wavelength of 790 nm. Figure 1 ,pass Figure 1It can be seen that an obvious light column appears in the liquid, namely the Tyndall effect, which shows that the prepared liquid is a sol and has the characteristics of a sol.

[0025] Example 2 This embodiment provides a method for preparing yttrium sol, comprising the following steps: 35 g of yttrium nitrate hexahydrate (Y(NO3)3·6H2O) was weighed on a balance and added to 20 ml of deionized water. The mixture was stirred on a magnetic stirrer for 1 h to completely dissolve the mixture, thereby obtaining solution A. 5 g of glacial acetic acid was added to solution A, and the mixture was placed in a 30°C water bath and stirred to dissolve the mixture. After uniform mixing, a mixed solution B was obtained. 5 g of ethylene glycol was added to solution B, and the mixture was placed in a 60°C water bath and reacted for 45 min to obtain yttrium sol.

[0026] Example 3 This embodiment provides a method for preparing yttrium sol, comprising the following steps: Weigh 45 g of yttrium nitrate hexahydrate (Y(NO3)3·6H2O) using a balance, add it to 20 ml of deionized water, and stir it on a magnetic stirrer for 1 hour to completely dissolve it, thereby obtaining solution A; add 5 g of glacial acetic acid to solution A, place it in a 30°C water bath, stir it to dissolve it, and mix it evenly to obtain a mixed solution B; add 5 g of ethylene glycol to solution B, place it in a 60°C water bath, and react for 45 minutes to obtain a yttrium sol.

[0027] Example 4 This embodiment provides a method for preparing yttrium sol, comprising the following steps: 40 g of yttrium chloride hexahydrate (YCl3·6H2O) was weighed on a balance and added to 20 ml of deionized water. The mixture was stirred on a magnetic stirrer for 1 h to completely dissolve the mixture, thereby obtaining solution A. 5 g of glacial acetic acid was added to solution A, and the mixture was placed in a 30°C water bath and stirred to dissolve the mixture. After uniform mixing, a mixed solution B was obtained. 5 g of ethylene glycol was added to solution B, and the mixture was placed in a 60°C water bath and reacted for 45 min to obtain yttrium sol.

[0028] Example 5 This embodiment provides a method for preparing yttrium sol, comprising the following steps: 40 g of yttrium sulfate was weighed on a balance, added to 20 ml of deionized water, and stirred on a magnetic stirrer for 1 hour to completely dissolve it to obtain solution A; 5 g of glacial acetic acid was added to solution A, placed in a 30°C water bath, stirred to dissolve it, and mixed evenly to obtain a mixed solution B; 5 g of ethylene glycol was added to solution B, placed in a 60°C water bath, and reacted for 45 minutes to obtain yttrium sol.

[0029] Comparative Example 1 This comparative example provides a method for preparing yttrium sol, comprising the following steps: Weigh 40 g of yttrium nitrate hexahydrate (Y(NO3)3·6H2O) using a balance, add it to 20 ml of deionized water, and stir it on a magnetic stirrer for 1 hour to completely dissolve it, thereby obtaining solution A. Then, add 30 g of ethylene glycol to solution A, place it in a 70°C water bath and continue stirring until the solution turns light yellow and releases brown gas. After reacting for 45 minutes, yttrium sol is obtained.

[0030] Comparative Example 2 This comparative example provides a method for preparing yttrium sol, comprising the following steps: Weigh 40 g of yttrium nitrate hexahydrate (Y(NO3)3·6H2O) using a balance, add it to 20 ml of deionized water, and stir it on a magnetic stirrer for 30 minutes to completely dissolve it, obtaining a transparent solution A; weigh 10 g of anhydrous citric acid and add it to solution A, continue stirring for 30 minutes to completely dissolve the citric acid, obtaining a mixed solution B; weigh 0.38 g of urea and continue stirring to dissolve it, obtaining a solution C; add concentrated ammonia water dropwise to solution C, adjust the pH to 7, and place it in an 80°C water bath and continue stirring for 45 minutes to finally obtain a yttrium sol.

[0031] Comparative Example 3 This comparative example provides a method for preparing yttrium sol, comprising the following steps: 40 g of yttrium nitrate hexahydrate (Y(NO3)3·6H2O) was weighed on a balance and added to 20 ml of deionized water. The mixture was stirred on a magnetic stirrer for 1 h to completely dissolve the solution, thereby obtaining solution A. 100 ml of concentrated aqueous ammonia was added dropwise to solution A, the reaction temperature was maintained at 10°C, and the mixture was reacted for 45 min to obtain a mixed solution B. The obtained mixed solution B was placed in an electrodialyzer to remove impurity ions, and yttrium sol was obtained after ultrasonic treatment.

[0032] Comparative Example 4 This comparative example provides a method for preparing yttrium sol, comprising the following steps: 40 g of yttrium nitrate hexahydrate (Y(NO3)3·6H2O) was weighed on a balance, added to 20 ml of deionized water, and stirred on a magnetic stirrer for 1 h to completely dissolve it, thereby obtaining solution A; 5 g of oxalic acid was added to solution A, and the mixture was placed in a 30°C water bath, stirred to dissolve it, and mixed evenly to obtain a mixed solution B; 5 g of ethylene glycol was added to solution B, and the mixture was placed in a 60°C water bath, and reacted for 45 min to obtain a yttrium sol.

[0033] Comparative Example 5 This comparative example provides a method for preparing yttrium sol, comprising the following steps: 40 g of yttrium nitrate hexahydrate (Y(NO3)3·6H2O) was weighed on a balance and added to 20 ml of deionized water. The mixture was stirred on a magnetic stirrer for 1 h to completely dissolve the mixture, thereby obtaining solution A. 5 g of L-malic acid was added to solution A, and the mixture was placed in a 30°C water bath and stirred to dissolve the mixture. After uniform mixing, a mixed solution B was obtained. 5 g of ethylene glycol was added to solution B, and the mixture was placed in a 60°C water bath and reacted for 45 min to obtain yttrium sol.

[0034] Comparative Example 6 This comparative example provides a method for preparing yttrium sol, comprising the following steps: 40 g of yttrium nitrate hexahydrate (Y(NO3)3·6H2O) was weighed on a balance and added to 20 ml of deionized water. The mixture was stirred on a magnetic stirrer for 1 h to completely dissolve the mixture, thereby obtaining solution A. 5 g of acrylic acid was added to solution A, and the mixture was placed in a 30°C water bath and stirred to dissolve the mixture. After uniform mixing, a mixed solution B was obtained. 5 g of ethylene glycol was added to solution B, and the mixture was placed in a 60°C water bath and reacted for 45 min to obtain yttrium sol.

[0035] Comparative Example 7 This comparative example provides a method for preparing yttrium sol, comprising the following steps: Weigh 40 g of yttrium nitrate hexahydrate (Y(NO3)3·6H2O) using a balance, add it to 20 ml of deionized water, and stir it on a magnetic stirrer for 1 hour to completely dissolve it, thereby obtaining solution A; add 5 g of glacial acetic acid to solution A, place it in a 30°C water bath, stir it to dissolve it, and mix it evenly to obtain a mixed solution B; add 5 g of ethylene glycol to solution B, place it in a 60°C water bath, and react for 45 minutes to obtain a yttrium sol.

[0036] Experimental example Determination of sol solid content: Determine the solid content of yttrium sol using the combustion method. First, weigh a clean crucible, m1, then add an appropriate amount of yttrium sol, weighing the total mass, m2. Place the weighed sol in a muffle furnace, heat it to 800°C, and hold it there for a while. Remove the calcined crucible and weigh the total mass, m3. Calculate the solid content, G, of the sol using the formula.

[0037] formula: The results are shown in Table 1: Table 1 Solid content of sol samples in Examples and Comparative Examples Conclusion: It can be seen from Table 1 that the sol prepared by the present invention has a higher solid content than that prepared by other methods.

[0038] Sol stability test The stability of the sol is primarily reflected by its zeta potential and the changes in its state during long-term storage. First, the zeta potential of different sols was measured, as shown in Table 2. The different sols were then placed in a cool, dry place at 25°C and their state changes were observed over a period of six months.

[0039] Table 2 Stability results of sol samples of Examples and Comparative Examples Conclusion: It can be seen from Table 2 that the absolute value of the Zeta potential of the yttrium sol prepared by the present invention is higher, more stable, and can be stably stored for more than 6 months.

[0040] Sol density determination: Take a 50 ml graduated cylinder and add 50 ml of the prepared sol. Estimate the sol density and place a hydrometer of the appropriate specifications in the cylinder, suspending it in the sol without touching the cylinder wall. Wait for the hydrometer to stabilize before reading the specific gravity. The test results are shown in Table 3.

[0041] Table 3 Average particle size test results of Examples and Comparative Examples Conclusion: It can be seen from Table 3 that the density of the yttrium sol prepared by the present invention can basically reach 1.5 g / cm 3 , combined with the results in Table 2, it can be seen that the sol prepared by the present invention has a higher density and can maintain better stability.

[0042] Sol particle size test: The sol particle size was measured using a laser particle size analyzer. The sol was diluted 10-20 times with nitric acid solution of the same pH and sonicated three times for 5 minutes each time. The diluted sol was added to a quartz cuvette, sonicated again for 5 minutes, and then placed in a laser particle size analyzer for analysis. The results are shown in Table 4.

[0043] Table 4 Average particle size test results of Examples and Comparative Examples Conclusion: It can be seen from Table 4 that the yttrium sol prepared by the present invention has a smaller particle size, which enhances the stability of the sol. At the same time, during the shell preparation and calcination steps, the smaller colloid particles can be more evenly wrapped between the matrix particles and have higher sintering activity, thereby promoting sintering.

[0044] Calcination test: The yttrium sol prepared in Example 1 was calcined at 800°C and the calcined crystals were tested by XRD. The results are shown in Figure 2 ,pass Figure 2It can be seen that the product after calcining the sol is Y2O3 without other impurities, which can ensure that the prepared shell has no other impurities after calcination.

[0045] Application Examples Application of yttrium sol in investment casting: 1. Raw materials Surface layer: 325 mesh zirconium oxide powder; surface layer binder: yttrium sol; back layer: 325 mesh mullite powder; back layer binder: silica sol.

[0046] 2. Preparation process (1) Take 30.0 g of yttrium sol in a plastic beaker, add 0.5% wetting agent and 0.5% defoaming agent; (2) Stirring with a small mixer at a speed of 200 r / min for 30 min; (3) Slowly add 60.0 g of zircon powder gradually while increasing the mixer speed to 300 r / min; (4) After adding powder, continue stirring for 12 h and use a viscosity cup to measure the viscosity of the slurry. When the viscosity is between 40-50 s, it can be used.

[0047] The preparation process of the back layer slurry is the same as above, the ratio of mullite powder to silica sol is 3:1, and the viscosity is between 16-20 s.

[0048] 3. Slurry coating The number of slurry coating layers and the raw materials used are shown in Table 5.

[0049] Table 5 Shell coating process Immerse the wax pattern in the yttrium sol topcoat slurry for 5-10 seconds, then remove it and evenly sprinkle it with 120-mesh zirconium oxide sand. Air-dry it for 12 hours. After the first layer is completely dried, immerse it again in the yttrium sol topcoat slurry. Follow the same steps for slurry and sand coating, and air-dry it. Once completely dry, apply the next layer of slurry. Apply the remaining layers according to the process specified in Table 1 to obtain the green shell.

[0050] 4. Shell demoulding Place the dried shell with the wax discharge port facing downward in an oven and slowly heat it to 120°C. After the wax pattern is completely discharged, cool it to room temperature.

[0051] 5. Shell firing Place the shell in a muffle furnace, first heat it up to 300℃ at a rate of 3℃ / min and keep it for 1h to remove the residual wax pattern and organic matter, then heat it up to 1000℃ at a rate of 3℃ / min and keep it for 1h, then heat it up to 1500℃ at a rate of 2℃ / min and keep it for 2h. Figure 3 shown.

[0052] 6. Shell performance testing The yttrium sol prepared in the present invention is mainly used for the preparation of the mold shell surface layer. The mold shell surface layer is in direct contact with the molten alloy during the casting process, so it needs to have high strength and density to resist the corrosion of the molten alloy. It is necessary to observe the porosity, bending strength and morphology of the mold shell.

[0053] (1) Shell porosity detection The porosity and bulk density of the shell are determined by the Archimedean method, see Figure 4 : (1) Dry the sample and weigh it (m1).

[0054] (2) Immerse the sample until it is completely saturated (usually by boiling or vacuum method) and weigh the mass of the sample in air after saturation (m3).

[0055] (3) Immerse the saturated sample in the liquid and weigh the suspended mass (m2).

[0056] Calculate the density and porosity according to the formula, see formula (1) and formula (2) The test results are shown in Table 6.

[0057] Table 6 Porosity and bulk density test results of the shells prepared with yttrium sol in the examples and comparative examples (2) Shell strength test Determination of shell strength at room temperature using three-point bending, see Figure 5 The test results are shown in Table 7.

[0058] Table 7 Surface layer strength test results of the shells prepared with yttrium sol in the examples and comparative examples (3) Shell morphology observation The microstructure of the shell of Example 1 was observed using a scanning electron microscope. Figure 6 .

[0059] pass Figure 6 It can be seen that the particles on the surface of the shell are evenly distributed without obvious defects, and the cross-section of the shell is relatively dense. The shell is relatively dense and can resist the erosion of the molten alloy.

[0060] Application of yttrium sol in high temperature anti-oxidation coating: Preparation of coating slurry: Yttrium sol and γ-Al2O3 powder (purity ≥99.5%, average particle size 50nm) were mixed in a mass ratio of 1:3, 2wt% yttrium nitrate (as a sintering aid) was added, and ultrasonic dispersion was performed for 40min to obtain a uniform slurry with a solid content of 60wt%.

[0061] Matrix pretreatment: The K4169 nickel-based alloy substrate was sandblasted (aluminum oxide sand, particle size 100-150 μm), ultrasonically cleaned with ethanol for 15 minutes, and dried for later use.

[0062] Coating and sintering: Atmospheric plasma spraying (APS) was used to atomize the slurry and then spray it onto the substrate surface. Spraying parameters were: 30kW power, 40L / min primary gas (Ar) flow, 5L / min secondary gas (H2) flow, 100mm spray distance, and a coating thickness of 150μm. After spraying, the coating was sintered at 1200°C for 2 hours and then cooled to room temperature.

[0063] Application of yttrium sol in corrosion-resistant materials: Preparation of corrosion-resistant coating: Yttrium sol and graphene (3-5 layers, lateral size 5-10 μm) were mixed in a mass ratio of 10:1, 5 wt% of epoxy resin (E-51) and 0.3 wt% of dibutyltin dilaurate (curing agent) were added, and high-speed stirring (1500 rpm) was performed for 1 h to obtain a uniform coating.

[0064] Steel pipe surface treatment: Shot blast the inner wall of Q345B steel pipe (Sa2.5 grade), apply epoxy primer (thickness 50μm), and dry it for 24 hours before use.

[0065] Coating application and curing: The corrosion-resistant coating is sprayed onto the inner wall of the steel pipe using an airless spray method. The coating thickness is controlled at 200 μm. After standing at room temperature for 1 hour, it is cured at 80°C for 4 hours. Finally, a 100 μm thick polyurethane topcoat is applied.

[0066] Although the principles of the present invention have been described in detail above in conjunction with the preferred embodiments of the present invention, those skilled in the art should understand that the above embodiments are merely illustrative of the present invention and are not intended to limit the scope of the present invention. The details in the embodiments do not constitute a limitation on the scope of the present invention. Without departing from the spirit and scope of the present invention, any obvious changes such as equivalent transformations and simple substitutions based on the technical solution of the present invention fall within the scope of protection of the present invention.

Claims

1. A method for preparing yttrium sol, characterized in that: The following steps are involved: Adding yttrium salt to water and stirring to dissolve to obtain solution A, then adding glacial acetic acid to the solution A and stirring to dissolve to obtain solution B; adding ethylene glycol to the solution B to react and obtain yttrium sol; Wherein, the mass ratio of the yttrium salt, glacial acetic acid and ethylene glycol is 7-9:1:

1.

2. The method for preparing yttrium sol according to claim 1, wherein The mass ratio of the yttrium salt, glacial acetic acid and ethylene glycol is 8:1:

1.

3. The method for preparing yttrium sol according to claim 1, wherein The yttrium salt is selected from one or more of yttrium nitrate hexahydrate, yttrium chloride hexahydrate or yttrium sulfate.

4. The method for preparing yttrium sol according to claim 1, wherein When preparing solution B, the temperature for stirring and dissolving is 20-30°C.

5. The method for preparing yttrium sol according to claim 1, wherein The reaction time is 30-60 min; and / or, The temperature of the reaction is 55-65°C.

6. A yttrium sol, characterized in that The product is prepared by the preparation method according to any one of claims 1 to 5.

7. The yttrium sol according to claim 6, characterized in that The solid content of the yttrium sol is ≥24%; and / or, The particle size of the yttrium sol is 8-20 nm; and / or, The zeta potential of the yttrium sol is 25-30 mV.

8. Use of yttrium sol prepared by the preparation method according to any one of claims 1 to 5 in investment casting.

9. Use of the yttrium sol prepared by the preparation method according to any one of claims 1 to 5 in a high-temperature anti-oxidation coating.

10. Use of the yttrium sol prepared by the preparation method according to any one of claims 1 to 5 in corrosion-resistant materials.

Images