Preparation method of modified aluminum sol for ceramic abrasive

Abstract

The invention belongs to the technical field of ceramic abrasive manufacturing, and particularly relates to a preparation method of modified aluminum sol for a ceramic abrasive. The method comprises the following steps: (1) mixing deionized water and hydrated alumina, uniformly stirring, adding a crystal form control agent and a surfactant, adding a coloring agent, a modifier and an adhesive, and uniformly stirring to obtain homogeneous slurry; and (2) adding a rare earth stabilizer into the homogenized slurry obtained in the step (1), then adding a nitric acid solution, homogenizing into transparent colloid, standing for 20-24 hours, dishing the precipitated colloid, drying, crushing and sieving to obtain the modified aluminum sol. The stabilizer and the modifier are added in the form of sol and are subjected to homogeneous reaction with the aluminum sol, so that the molecular weight distribution is more uniform, the particle size is smaller, and the distribution is narrower.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic abrasive production, and particularly relates to a method for preparing modified aluminum sol for ceramic abrasive. Background Art

[0002] With the continuous development of modern industry, high-end manufacturing has an increasing demand for high-precision and high-efficiency processing. Ceramic abrasives are widely used in high-precision grinding due to their high hardness and good wear resistance. At present, the commonly used ceramic abrasive preparation methods, such as the invention patent "A method for preparing high-density nano-ceramic grinding materials", are published with the publication number CN 112939587 A. This preparation method uses special alumina wet material as raw material, and mixes the special alumina wet material with deionized water in a ratio of 1:1-4 to obtain a suspension; then, a seeding agent and an inhibitor are added to the obtained suspension and mixed evenly, and then an inorganic acid is added to adjust the pH to 2-4 to obtain an alumina gel; the total amount of the seeding agent and the inhibitor added is 5% of the weight of the special alumina wet material; the obtained alumina gel is evenly spread on the belt of the drying equipment for drying, and the spreading thickness is 2-5cm; the dried The colloid is conveyed to a drying device by a belt and dried at 80-140°C for 24 hours to obtain a dry colloid; the obtained dry colloid is crushed and sieved, and the required number segments are put into a medium-temperature calcination rotary furnace for calcination at a temperature of 600°C and a time of 30 minutes to obtain a medium-temperature calcined material; the medium-temperature calcined material is put into a high-temperature rotary furnace for calcination at a temperature of 1400-1500°C and a time of 20-40 minutes, and the particles after high-temperature calcination are finely sieved to obtain nano-ceramic grinding materials of different particle sizes. However, the abrasives produced by this method have low hardness and poor self-sharpening properties, and cannot meet the high-precision and high-strength cutting effects. Therefore, the existing technology needs further improvement. Summary of the Invention

[0003] The object of the present invention is to provide a method for preparing modified aluminum sol for ceramic abrasive.

[0004] Based on the above objectives, the present invention adopts the following technical solutions: A method for preparing a modified aluminum sol for ceramic abrasives comprises the following steps: (1) mixing deionized water and hydrated aluminum oxide, stirring uniformly, adding a crystal form control agent, a surfactant, and then adding a colorant, a modifier, and an adhesive, and stirring uniformly to obtain a homogeneous slurry; (2) Add a rare earth stabilizer to the homogenized slurry in step (1), and then add a nitric acid solution, homogenize into a transparent colloid, let it stand for 20-24 hours, and place the colloid after precipitation on a plate for drying, crushing, and sieving to obtain the modified aluminum sol.

[0005] Furthermore, the surfactant is hexadecyltrimethylammonium bromide or N,N-dimethylurea; and the colorant is cobalt nitrate.

[0006] Furthermore, the mass volume ratio of the deionized water, hydrated alumina, crystal form control agent, surfactant, colorant, rare earth stabilizer, modifier, adhesive, and nitric acid solution is 900-1000 ml: 90-110 g: 2.15-5 g: 0.6-1.4 g: 0.12-0.5 g: 4.05-8 g: 0.64-40.5 g: 5-10 g: 25-50 ml.

[0007] Furthermore, the rare earth stabilizer is a rare earth sol stabilizer, which is prepared by the following steps: (1) uniformly mixing deionized water and a rare earth mixed material, adding a sodium hydroxide solution, and adjusting the pH to 8 to obtain a rare earth mixed solution; (2) adding urea to the rare earth mixed solution in step (1), stirring at 140-145°C at a speed of 300-500 rpm for 20-24 hours, cooling and filtering to obtain a gel solid, washing it with water three times, and drying it at 60-80°C to obtain a rare earth sol stabilizer. The modifier is chromium nitrate.

[0008] Furthermore, the rare earth mixed material is a mixed material of cerium chloride, lanthanum chloride and yttrium chloride.

[0009] Furthermore, the rare earth stabilizer is lanthanum nitrate or yttrium nitrate; and the modifier is chromium sol.

[0010] Furthermore, the rare earth stabilizer is lanthanum nitrate or yttrium nitrate; and the modifier is zirconium sulfate.

[0011] Furthermore, the rare earth stabilizer is yttrium nitrate; and the modifier is zirconium sol.

[0012] Furthermore, the adhesive is obtained by mixing polyvinyl alcohol and deionized water at 80-100° C., wherein the mass volume ratio of polyvinyl alcohol to deionized water is 10-15 g:90-100 ml, and the crystal form control agent is magnesium aluminum silicate; Furthermore, the modifier is prepared by the following steps: (1) uniformly mixing deionized water and chromium nitrate, adding sodium hydroxide solution, and adjusting the pH to 7-8 to obtain a chromium hydroxide mixed solution; (2) adding ammonia water to the chromium hydroxide mixed solution in step (1), stirring at 400-500 rpm at 60-90°C for 22-24 hours, cooling to 30-35°C, filtering to obtain a gel solid, washing with water three times, and drying at 60-70°C to obtain the modifier. The mass percentage of the nitric acid solution is 20-40%.

[0013] The aluminum sol prepared by the aluminum sol preparation method is used to prepare ceramic abrasives.

[0014] The present invention adds a stabilizer and a modifier in the form of a sol and reacts them with the aluminum sol in a homogeneous phase, thereby making the molecular weight distribution more uniform, the particle size smaller, and the distribution narrower. The microcrystalline ceramic abrasive prepared from the modified aluminum sol prepared by the present invention has the characteristics of high hardness, strong self-sharpening ability, good wear resistance, and good chemical stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a scanning electron microscope image of the ceramic abrasive obtained in Example 2; Figure 2 This is a scanning electron microscope image of the ceramic abrasive prepared in Example 2. DETAILED DESCRIPTION

[0016] Example 1:

[0017] A method for preparing a modified aluminum sol for ceramic abrasives comprises the following steps: (1) mixing deionized water and hydrated aluminum oxide, stirring uniformly, adding a crystal form control agent, a surfactant, and then adding a colorant, a modifier, and an adhesive, and stirring uniformly to obtain a homogeneous slurry; Add a rare earth stabilizer to the homogenized slurry in step (1), and then add a nitric acid solution, homogenize into a transparent colloid, let it stand for 20-24 hours, and the colloid after precipitation is placed on a plate for drying, crushing, and sieving to obtain the modified aluminum sol.

[0018] The surfactant is hexadecyltrimethylammonium bromide and the colorant is cobalt nitrate.

[0019] The mass volume ratio of the deionized water, hydrated alumina, crystal form control agent, surfactant, colorant, rare earth stabilizer, modifier, adhesive and nitric acid solution is 900ml:90g:2.15g:0.6g:0.23g:4.05g:0.64g:5g:25ml.

[0020] The rare earth stabilizer is a rare earth sol stabilizer, which is prepared by the following steps: (1) uniformly mixing deionized water and a rare earth mixed material, adding a sodium hydroxide solution, and adjusting the pH value to 8 to obtain a rare earth mixed solution; (2) adding urea to the rare earth mixed solution in step (1), stirring at 140°C and 300 rpm for 20 hours, cooling and filtering to obtain a gel solid, washing it with water three times, and drying it at 60°C to obtain a rare earth sol stabilizer. The modifier is chromium nitrate.

[0021] In the above-mentioned rare earth stabilizer preparation method, the mass volume ratio of deionized water, rare earth mixed material, and urea is 100 ml: 5.15 g: 1.16 g. The mass fraction of the sodium hydroxide solution is 20%.

[0022] The rare earth mixed material is a mixed material of cerium chloride, lanthanum chloride and yttrium chloride; the cerium chloride accounts for 49.5% of the total mass of the rare earth mixed material; the lanthanum chloride accounts for 25.5% of the total mass of the rare earth mixed material; and the yttrium chloride accounts for 25% of the total mass of the rare earth mixed material.

[0023] The adhesive is prepared by mixing polyvinyl alcohol and deionized water at 80° C., wherein the mass volume ratio of the polyvinyl alcohol to the deionized water is 10 g:90 ml. The crystal form control agent is magnesium aluminum silicate.

[0024] The mass percentage of the nitric acid solution is 20%.

[0025] The alumina sol prepared by the above-described alumina sol preparation method is used to prepare ceramic abrasives. The method comprises heating the modified alumina sol prepared above at a rate of 1°C per minute to 200°C, then at a rate of 3°C per minute to 800°C, and then rapidly heating to 1400°C. After holding the temperature for 60 minutes, the temperature is naturally cooled to room temperature. Thus, the microcrystalline ceramic abrasives are obtained.

[0026] Example 2: A method for preparing a modified aluminum sol for ceramic abrasives comprises the following steps: (1) mixing deionized water and hydrated aluminum oxide, stirring uniformly, adding a crystal form control agent, a surfactant, and then adding a colorant, a modifier, and an adhesive, and stirring uniformly to obtain a homogeneous slurry; (2) Add a rare earth stabilizer to the homogenized slurry in step (1), and then add a nitric acid solution, homogenize into a transparent colloid, let it stand for 20-24 hours, and place the colloid after precipitation on a plate for drying, crushing, and sieving to obtain the modified aluminum sol.

[0027] The surfactant is N,N-dimethylurea and the colorant is cobalt nitrate.

[0028] The mass volume ratio of the deionized water, hydrated alumina, crystal form control agent, surfactant, colorant, rare earth stabilizer, modifier, adhesive and nitric acid solution is 950ml:100g:3g:0.8g:0.5g:5g:20g:8g:30ml.

[0029] The rare earth stabilizer is lanthanum nitrate and yttrium nitrate, wherein the lanthanum nitrate accounts for 65% of the total mass of the rare earth stabilizer and the yttrium nitrate accounts for 35% of the total mass of the rare earth stabilizer. The modifier is chromium sol.

[0030] The adhesive is prepared by mixing polyvinyl alcohol and deionized water at 90°C in a mass-to-volume ratio of 12g:95ml. The crystal form control agent is magnesium aluminum silicate; The modifier is prepared by the following steps: (1) mixing deionized water and chromium nitrate uniformly, adding sodium hydroxide solution, and adjusting the pH value to 7 to obtain a chromium hydroxide mixed solution; (2) adding ammonia water to the chromium hydroxide mixed solution in step (1), stirring at 80°C and 450rpm for 23h, cooling to 32°C, filtering to obtain a gel solid, washing with water three times, and drying at 65°C to obtain a modifier.

[0031] In the above-mentioned method for preparing the modifier, the mass volume ratio of deionized water, chromium nitrate and ammonia water is 100 ml: 6.6 g: 0.78 g.

[0032] The mass fraction of ammonia water is 30%. The mass fraction of the nitric acid solution is 30%.

[0033] Ceramic abrasive is prepared using the aluminum sol prepared by the aforementioned aluminum sol preparation method. The method involves heating the modified aluminum sol prepared above to 200°C at 1°C per minute, then to 800°C at 3°C ​​per minute, and then rapidly heating to 1500°C. After holding the temperature for 80 minutes, the temperature is naturally cooled to room temperature. Microcrystalline ceramic abrasive is thus obtained.

[0034] Example 3: A method for preparing a modified aluminum sol for ceramic abrasives comprises the following steps: (1) mixing deionized water and hydrated aluminum oxide, stirring uniformly, adding a crystal form control agent, a surfactant, and then adding a colorant, a modifier, and an adhesive, and stirring uniformly to obtain a homogeneous slurry; (2) Add a rare earth stabilizer to the homogenized slurry in step (1), and then add a nitric acid solution, homogenize into a transparent colloid, let it stand for 20-24 hours, and place the colloid after precipitation on a plate for drying, crushing, and sieving to obtain the modified aluminum sol.

[0035] The surfactant is hexadecyltrimethylammonium bromide and the colorant is cobalt nitrate.

[0036] The mass volume ratio of the ionized water, hydrated alumina, crystal form control agent, surfactant, colorant, rare earth stabilizer, modifier, adhesive and nitric acid solution is 1000ml: 100g: 4g: 0.9g: 0.13g: 6g: 11g: 8g: 50ml.

[0037] The rare earth stabilizer is lanthanum nitrate and yttrium nitrate, with lanthanum nitrate accounting for 71% of the total mass of the rare earth stabilizer and yttrium nitrate accounting for 29% of the total mass of the rare earth stabilizer. The modifier is zirconium sulfate.

[0038] The adhesive is prepared by mixing polyvinyl alcohol and deionized water at 90° C., wherein the mass volume ratio of polyvinyl alcohol to deionized water is 12 g:100 ml. The crystal form control agent is magnesium aluminum silicate.

[0039] The mass percentage of the nitric acid solution is 40%.

[0040] Ceramic abrasive is prepared from the aluminum sol prepared by the aforementioned aluminum sol preparation method. The modified aluminum sol prepared above is heated at a rate of 1°C per minute to 200°C, then at a rate of 3°C per minute to 800°C, and then rapidly heated to 1600°C. After holding the temperature for 90 minutes, the temperature is naturally cooled to room temperature. Microcrystalline ceramic abrasive is thus obtained.

[0041] Example 4: A method for preparing a modified aluminum sol for ceramic abrasives comprises the following steps: (1) mixing deionized water and hydrated aluminum oxide, stirring uniformly, adding a crystal form control agent, a surfactant, and then adding a colorant, a modifier, and an adhesive, and stirring uniformly to obtain a homogeneous slurry; (2) Add a rare earth stabilizer to the homogenized slurry in step (1), and then add a nitric acid solution, homogenize into a transparent colloid, let it stand for 20-24 hours, and place the colloid after precipitation on a plate for drying, crushing, and sieving to obtain the modified aluminum sol.

[0042] The surfactant is N,N-dimethylurea and the colorant is cobalt nitrate.

[0043] The mass volume ratio of the deionized water, hydrated alumina, crystal form control agent, surfactant, colorant, rare earth stabilizer, modifier, adhesive and nitric acid solution is 1000ml:110g:5g:1.4g:0.14g:8g:40.5g:10g:50ml.

[0044] The rare earth stabilizer is yttrium nitrate, and the modifier is zirconium sol.

[0045] The adhesive is prepared by mixing polyvinyl alcohol and deionized water at 100° C., wherein the mass volume ratio of the polyvinyl alcohol to the deionized water is 15 g:100 ml. The crystal form control agent is magnesium aluminum silicate.

[0046] The mass fraction of ammonia water is 30%.

[0047] The mass percentage of the nitric acid solution is 40%.

[0048] Ceramic abrasive is prepared from the aluminum sol prepared by the aforementioned aluminum sol preparation method. The method involves heating the modified aluminum sol prepared above to 200°C at 1°C per minute, then to 800°C at 3°C ​​per minute, and then rapidly heating to 1700°C. After holding the temperature for 120 minutes, the temperature is naturally cooled to room temperature. Microcrystalline ceramic abrasive is thus obtained.

[0049] Test Example 1: The morphology of the ceramic abrasive prepared in Example 2 was scanned using an electron microscope, and the results were as follows: Figure 1 and Figure 2 As shown by Figure 1 、 2 It can be seen that the ceramic abrasive prepared by the present invention has a dense structure and a smaller particle size.

[0050] Test Example 2: The microhardness and bulk density of the ceramic abrasives prepared in Example 1, Example 2, Example 3 and Example 4 of the present invention were tested respectively. Table 1: Results of microhardness and bulk density of ceramic abrasives in Example 1: Test items unit Test results Testing basis Microhardness HV0.2 1820 ASTM E384-2017 Bulk density <![CDATA[g / mm 3 ]]> 3.83 GB / T 2999-2016 Table 2: Results of microhardness and bulk density of ceramic abrasives in Example 2: Test items unit Test results Testing basis Microhardness HV0.2 1931 ASTM E384-2017 Bulk density <![CDATA[g / mm 3 ]]> 3.89 GB / T 2999-2016 Table 3: Microhardness and bulk density results of ceramic abrasives in Example 3: Test items unit Test results Testing basis Microhardness HV0.2 1935 ASTM E384-2017 Bulk density <![CDATA[g / mm 3 ]]> 4.13 GB / T 2999-2016 Table 4: Results of microhardness and bulk density of ceramic abrasives in Example 4: Test items unit Test results Testing basis Microhardness HV0.2 1970 ASTM E384-2017 Bulk density <![CDATA[g / mm 3 ]]> 4.32 GB / T 2999-2016 As can be seen from the above, the ceramic abrasive prepared using the modified aluminum sol prepared in the present invention has high hardness, good self-sharpening property, and high bulk density, which is conducive to cutting and grinding.

Claims

1. A method for preparing modified aluminum sol for ceramic abrasive, characterized in that: The method comprises the following steps: (1) mixing deionized water and hydrated alumina and stirring them uniformly, adding a crystal form control agent and a surfactant, and then adding a colorant, a modifier, and an adhesive, and stirring them uniformly to obtain a homogeneous slurry; (2) Add a rare earth stabilizer to the homogenized slurry in step (1), and then add a nitric acid solution, homogenize into a transparent colloid, let it stand for 20-24 hours, and place the colloid after precipitation on a plate for drying, crushing, and sieving to obtain the modified aluminum sol.

2. The method for preparing the modified aluminum sol for ceramic abrasive according to claim 1, wherein: The surfactant is hexadecyltrimethylammonium bromide or N,N-dimethylurea; the adhesive is obtained by mixing polyvinyl alcohol and deionized water at 80-100° C., wherein the mass volume ratio of the polyvinyl alcohol to the deionized water is 10-15 g:90-100 ml, to obtain the adhesive; the crystal form control agent is magnesium aluminum silicate; and the colorant is cobalt nitrate.

3. The method for preparing the modified aluminum sol for ceramic abrasive according to claim 1, wherein: The mass volume ratio of the deionized water, hydrated alumina, crystal form control agent, surfactant, colorant, rare earth stabilizer, modifier, adhesive and nitric acid solution is 900-1000 ml: 90-110 g: 2.15-5 g: 0.6-1.4 g: 0.12-0.5 g: 4.05-8 g: 0.64-40.5 g: 5-10 g: 25-50 ml.

4. The method for preparing the modified aluminum sol for ceramic abrasive according to claim 3, wherein: The rare earth stabilizer is a rare earth sol stabilizer, which is prepared by the following steps: (1) uniformly mixing deionized water and a rare earth mixed material, adding a sodium hydroxide solution, and adjusting the pH value to 8 to obtain a rare earth mixed solution; (2) adding urea to the rare earth mixed solution in step (1), stirring at 140-145°C at a speed of 300-500 rpm for 20-24 hours, cooling and filtering to obtain a gel solid, washing it with water three times, and drying it at 60-80°C to obtain the rare earth sol stabilizer. The modifier is chromium nitrate.

5. The method for preparing the modified aluminum sol for ceramic abrasive according to claim 4, characterized in that: The rare earth mixed material is a mixed material of cerium chloride, lanthanum chloride and yttrium chloride.

6. The method for preparing the modified aluminum sol for ceramic abrasive according to claim 3, wherein: The rare earth stabilizer is lanthanum nitrate and yttrium nitrate; the modifier is chromium sol.

7. The method for preparing the modified aluminum sol for ceramic abrasive according to claim 3, characterized in that: The rare earth stabilizer is lanthanum nitrate and yttrium nitrate; the modifier is zirconium sulfate.

8. The method for preparing the modified aluminum sol for ceramic abrasive according to claim 3, wherein: The rare earth stabilizer is yttrium nitrate; and the modifier is zirconium sol.

9. The method for preparing the modified aluminum sol for ceramic abrasive according to claim 6, wherein: The modifier is prepared by the following steps: (1) mixing deionized water and chromium nitrate uniformly, adding sodium hydroxide solution, and adjusting the pH value to 7-8 to obtain a chromium hydroxide mixed solution; (2) adding ammonia water to the chromium hydroxide mixed solution in step (1), stirring at 60-90°C and 400-500rpm for 22h-24h, cooling to 30-35°C, filtering to obtain a gel solid, washing with water three times, and drying at 60-70°C to obtain the modifier.

10. Ceramic abrasive prepared by the aluminum sol prepared by the aluminum sol preparation method according to any one of claims 1 to 9.

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