Novel ceramic abrasive material and preparation method of dry abrasive paper of novel ceramic abrasive material

Abstract

The invention relates to the field of novel precise grinding materials and grinding tools thereof, in particular to a novel ceramic grinding material and a preparation method of dry abrasive paper of the novel ceramic grinding material. Through innovative optimization of added materials in an abrasive material preparation system and optimization of key process conditions, the preparation method specifically comprises the step of adding a composite seed crystal and a composite additive into a novel ceramic abrasive material preparation formula, and the novel ceramic abrasive material adopts a two-step staged heat preservation sintering method in a sintering stage. The performance of the new abrasive material in all aspects is improved, the grinding efficiency of the grinding tool is improved, the loss rate of the abrasive material is reduced, and the conditions of abnormal heating and reduction of the grinding efficiency caused by the fact that the abrasive material falls off and is blocked in the using process of the grinding tool are effectively prevented.

Description

Technical Field

[0001] The present invention relates to the field of new materials for precision grinding and their abrasives, and specifically relates to a new type of ceramic abrasive and a preparation method of dry abrasive paper. Background Art

[0002] Grinding is a very important processing method in material cold processing technology, usually used for finishing or semi-finishing of materials. It is of great significance to prepare high-end abrasives. Abrasives of abrasives are divided into natural abrasives and artificial abrasives. According to the hardness of the abrasives, they can be further divided into ordinary abrasives and superhard abrasives. As one of the emerging and most promising abrasives, the preparation method of ceramic corundum has important research value.

[0003] There are various methods for preparing ceramic corundum, including sol-gel method, chemical co-precipitation method, hydrothermal method, powder sintering method, solid-phase thermal decomposition method, self-propagating high-temperature synthesis method, corundum abrasive coating method, and so on. Among them, the sol-gel method has relatively good comprehensive preparation. It uses liquid chemical reagents (or dissolves powdered reagents in liquid-phase solvents) or sols as raw materials instead of traditional powdered materials. The reactants are uniformly mixed and reacted in the liquid phase, and the reaction product is a stable sol system; after standing for a period of time, it turns into a gel, the liquid medium is evaporated and removed, and then the gel is dried; the dry gel precursor is calcined to remove organic components and bound water, and finally the required product is obtained.

[0004] Currently reported patents related to the preparation of precision grinding materials and abrasives include those for improving the preparation material system and those for optimizing by changing the preparation process parameters. The optimization directions are mostly to optimize specific parameters, add new reagent materials, etc. For example, Chinese Patent CN112171530A discloses a ceramic corundum abrasive coated abrasive tool and its preparation method. Among them, the ceramic corundum abrasive coated abrasive tool includes a base material layer and a working layer. The working layer includes a base glue layer, abrasives implanted in the base glue layer, and a top glue layer coated on the abrasives and the base glue. The feature is that the abrasives are ceramic corundum abrasives treated by ion implantation. The above-mentioned ceramic corundum abrasive coated abrasive tool does not need to change the internal properties of the abrasives. Through surface modification by ion implantation, ions are implanted into the surface of the abrasives to achieve the synergistic improvement of surface hardening, strengthening and toughening of the abrasives. The abrasives are not easy to break and not easy to fall off from the base glue layer, and when the abrasive grains bear a large load, they can break to improve the self-sharpening of the abrasives, greatly improve the surface performance of the abrasives, and thus increase the service performance of the overall abrasive tool, so that the coated abrasive tool can meet the performance requirements of precision high-speed, precision heavy-load high-strength grinding and polishing while having a long service life. Chinese Patent CN116789459A discloses a ceramic corundum abrasive and its preparation method and application. Using industrial-grade pseudo-boehmite as the raw material, by adding a peptizing agent HNO 3Form a double - electron layer structure of pseudo - boehmite colloidal particles, prepare pseudo - boehmite sol, and prepare the finished abrasive through processes such as sol - gel, crushing, classification, and sintering. Specific modified components are introduced during the sol preparation and sintering processes respectively to promote the sol - gel process and improve the product performance, while also improving production efficiency, which has great market value.

[0005] In summary, existing inventions often focus on optimizing certain key parameters or introducing a certain modified auxiliary material in the preparation of ceramic corundum abrasives and grinding tools, but none of them consider the materials and process conditions of the preparation system to significantly improve the performance of ceramic corundum materials. Summary of the Invention

[0006] Based on the above - summarized problems, the present invention provides a preparation method of a new type of ceramic abrasive and its dry abrasive paper. Its main feature is that through the innovative optimization of the added materials and the optimization of key process conditions in the abrasive preparation system, the performance of the ceramic corundum abrasive reaches a relatively high level when the abrasive is formed, and the grinding efficiency and abrasive retention of the manufactured grinding tool are greatly improved. The specific technical solutions are as follows:

[0007] A preparation method of a new type of ceramic abrasive. The preparation formula of the new type of ceramic abrasive includes a composite seed crystal and a composite additive, and a two - step sintering process is adopted in the sintering stage of the new type of ceramic abrasive.

[0008] The preparation method of the new type of ceramic abrasive includes the following steps:

[0009] Step 1: Prepare a composite seed crystal. Use alumina hydrate as the main raw material to make a gel, then introduce a metal oxide and SiO 2 to form a mixture with the composite additive composed of it. Ball - mill the mixture and then dry it, and then perform crushing and classification. Select particles within a certain range of mesh numbers for sintering to obtain the composite seed crystal;

[0010] Step 2: Prepare an abrasive gel. Use alumina hydrate as the main raw material, add a dispersant to configure it into a suspension, fully stir it in a water - bath environment, then add an acid to adjust the pH to an appropriate range, and repeat the water - bath stirring and then age it at room temperature;

[0011] Step 3: Prepare an abrasive precursor. After washing the gel obtained in Step 2 with deionized water, add a metal oxide and SiO 2 to form a composite additive, and then add the composite seed crystal prepared in Step 1. Ball - mill the mixture and then dry it;

[0012] Step 4: Abrasive sintering. Crush the abrasive precursor obtained in Step 3 and then place it in a sintering furnace for atmospheric sintering. The sintering is divided into two stages: rapid temperature rise and constant - temperature holding.

[0013] The composite seed described in Step 1 is a composite secondary seed;

[0014] The aluminum hydrate described in Step 1 is at least one of pseudoboehmite, aluminum hydroxide, boehmite or boehmite monohydrate;

[0015] The metal oxide described in Step 1 is MgO, CaO and α-Al 2 O 3 , the addition amount of the MgO-CaO-SiO 2 is 2.5 wt.%, the molar ratio is 5:1:5, and the addition amount of α-Al 2 O 3 is 3.0 wt.%;

[0016] The particles with a certain mesh number described in Step 1 have a mesh number range between 60 and 120 meshes.

[0017] The aluminum hydrate described in Step 2 is at least one of pseudoboehmite, aluminum hydroxide, boehmite or boehmite monohydrate;

[0018] The dispersant described in Step 2 is at least one of ammonium citrate, ammonium polyacrylate or PEG;

[0019] The pH-adjusting acid described in Step 2 is at least one of HNO 3、 citric acid 、 hydrochloric acid;

[0020] The pH value in the appropriate range described in Step 2 is 2-3.

[0021] The metal oxide described in Step 3 is MgO, TiO 2 , the addition amount of the MgO-TiO 2 -SiO 2 is 2.0 wt.%, and the molar ratio is 3:5:11;

[0022] The addition amount of the composite seed prepared in Step 1 described in Step 3 is 2.0 wt.% - 3.5 wt.%.

[0023] Preferably, the addition amount of the composite seed is 2.5 wt.%

[0024] The heating rate of the rapid heating described in Step 4 is 5 °C / min, and the final temperature after heating is 1350 °C;

[0025] The constant-temperature heat preservation stage described in Step 4 includes a first stage and a second stage.

[0026] In the first stage of the heat preservation stage, the heat preservation temperature is 1050°C - 1250°C, and the heat preservation time is 1 hour. In the second stage, the heat preservation temperature is 950°C, and the heat preservation time is 4 hours.

[0027] Preferably, the heat preservation temperature in the first stage of the heat preservation stage is 1150°C.

[0028] A preparation method of a new type of ceramic abrasive dry sandpaper includes the following steps: substrate treatment → applying primer → sand planting → pre-drying → applying topcoat → applying anti-blocking coating → drying → winding → rewetting → parking → finished product.

[0029] The substrate is made of a composite substrate composed of flexible latex paper and PET film. The substrate treatment step includes substrate flexibility detection and surface leveling treatment;

[0030] The binder of the primer is a flexible resin;

[0031] The sand planting adopts a low-density sand planting process. In the sand planting step, the new type of ceramic abrasive is classified, and the first 1 / 3 - 1 / 2 of the particle size and ordinary abrasive are mixed in a ratio of 30% - 50%;

[0032] Thermosetting novolac resin, NBR, acrylic emulsion and antistatic agent are added to the topcoat.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) In the preparation of the new material abrasive of the present invention, a composite secondary seed crystal is added, which can well guide the formation of homogeneous grains below 100 nanometers. It can induce the rapid formation of a large number of tiny homogeneous grains at the initial stage of rapid heating during sintering, accelerating the densification speed of the whole system and ensuring the improvement of the performance of the final abrasive new material in all aspects.

[0035] (2) In the sintering stage of the new material abrasive of the present invention, a two-step stage heat preservation sintering method is adopted. It cooperates with the previous composite secondary seed crystal and composite additive, and can provide appropriate energy intensity for the system at different stages of sintering, which can not only drive the densification and growth of grains, but also will not cause the distortion of grain arrangement and morphology, ensuring the performance of the abrasive new material in all aspects.

[0036] (3) In the preparation and testing stage of the abrasive tool of the present invention, process methods such as low-density sand planting, adding antistatic agent, and increasing anti-blocking coating are adopted, which improve the grinding efficiency of the abrasive tool, reduce the abrasive loss rate, and combine with the excellent fracture toughness performance of the abrasive new material itself, effectively preventing the abnormal heating and the decline of grinding efficiency caused by excessive falling and blocking of abrasives during the use of the abrasive tool. Description of the Drawings

[0037] Figure 1It is the flowchart for the preparation of the novel ceramic abrasive of the present invention;

[0038] Figure 2 It is the comparative broken line graph of two parameters, namely the single-particle compressive strength and relative density, of the abrasive samples in Examples 1-4 and Comparative Example 1;

[0039] Figure 3 It is the comparative broken line graph of two parameters, namely the hardness and fracture toughness, of the abrasive samples in Examples 1-4 and Comparative Example 1;

[0040] Figure 4 It is the microscopic structure diagram of the small ceramic corundum grains of the additive system used for the preparation of the composite secondary seed crystal;

[0041] Figure 5 It is the comparative microscopic structure diagram of the novel ceramic abrasives prepared in Comparative Example 1 (left figure) and Example 2 (right figure);

[0042] Figure 6 It is the comparative broken line graph of two parameters, namely the single-particle compressive strength and relative density, of the abrasive samples in Examples 2, 5, 6 and Comparative Example 2;

[0043] Figure 7 It is the comparative broken line graph of two parameters, namely the hardness and fracture toughness, of the abrasive samples in Examples 2, 5, 6 and Comparative Example 2. Detailed implementation manners

[0044] The following examples further explain and illustrate the technical solutions of the present invention. It is particularly pointed out that each specific implementation manner is a concretization and interpretation of the technical solution, and should not be regarded as a limitation on the protection scope of the present invention. Those of ordinary skill in the art still have the right to modify the technical solutions of these examples and perform equivalent replacements on some or all of the technical features, and these modifications or replacements do not change the essence of the corresponding technical solutions and do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions described in the present invention.

[0045] The reagents and instruments used in the examples can be purchased from the market, and the detection methods adopt the conventional methods well-known in the art; based on the technical requirements of precision grinding, the detection is mainly carried out on several aspects such as the single-particle compressive strength, relative density, hardness, fracture toughness, microscopic structure of the novel ceramic abrasive and the grinding performance of the abrasive tool samples made.

[0046] 1. Single-particle compressive strength test:

[0047] The single-particle compressive strength test of ceramic corundum abrasive is carried out on a diamond static pressure strength tester. According to JB / T7988.1-1999 "Determination Method for Compressive Strength of Synthetic Diamond or Cubic Boron Nitride", the compressive strength refers to the load value when a single-particle abrasive breaks under static pressure, expressed in Newtons (N). Take 1.5 g of abrasive, evenly place it on a slide, scrape it into a straight line, and then pick 40 grains from the slide in turn to measure their breaking loads. The arithmetic mean value obtained is the single-particle compressive strength of the abrasive at this particle size. All the abrasives measured in the experiment are between 60 / 80 mesh.

[0048] 2. Relative density test:

[0049] The Archimedes drainage method is used to test the density of the material. Before measuring the density, the abrasive particles are dried to a constant weight at 110 °C and placed in a desiccator to cool to room temperature. Then the abrasive particles are weighed, and the recorded mass is m (the measured abrasive is generally not less than 1 / 3 of the volume of the pycnometer and not more than 1 / 2). Pour the abrasive into the pycnometer, evacuate for 5 minutes, inject distilled water to submerge the abrasive, and continue to evacuate for 15 minutes. Fill the pycnometer with distilled water, and record the mass of the pycnometer filled with abrasive and distilled water as m 2 . Pour out the abrasive and distilled water in the pycnometer, clean it, refill it with distilled water, and measure the mass of the pycnometer filled with distilled water as m 1 , and the density formula of the abrasive is calculated as follows:

[0050]

[0051] In the formula, ρ s is the effective density of the abrasive particles, g·cm -3 ; ρ is the density of distilled water corresponding to the measurement temperature, g·cm -3 ; m is the mass of the abrasive, g; m 1 is the mass of the pycnometer filled with water, g; m 2 is the mass of the pycnometer filled with water and the abrasive.

[0052] 3. Hardness test:

[0053] A Vickers microhardness tester is used to measure the hardness value of the material. Before the test, the surface of the specimen is polished to a mirror surface, the load is 5 kg, and the test result is based on the average value of 5 hardness values at different positions of the same specimen. The Vickers hardness H V is calculated by the following formula:

[0054]

[0055] In the formula, Hv is the Vickers hardness, MPa; P is the applied load, N; d is the average length of the diagonal of the indentation, mm.

[0056] 4. Toughness Test:

[0057] The fracture toughness is calculated by the Vicker indentation method, and its calculation formula is as follows:

[0058]

[0059] In the formula, K IC is the fracture toughness of the sample, MPa·cm 1 / 2 ; E is the Young's modulus of alumina, GPa; H v is the Vickers hardness, MPa; P is the applied load, N; c is the average crack length, mm.

[0060] 5. Microstructure Observation

[0061] The surface microstructure of the abrasive sample is analyzed by a field emission scanning electron microscope, and the grain size is measured by the linear intercept method. The formula is as follows:

[0062]

[0063] In the formula is the average grain size, 1.56 is the correction coefficient, C is the length of the intercepted line segment, N is the number of intercepted points, and M is the magnification of the photo.

[0064] 6. Grinding Performance Test

[0065] Referring to JBT 10155-2012 "Test Methods for Grinding Performance of Coated Abrasives - Sand Cloth and Sand Paper" and the actual requirements of the test, the abrasive sample is made into a circular sheet sample with an outer diameter of 165 mm ± 2 mm and an inner diameter of 10 - 20 mm and tested with a grinding performance tester. Parameter settings: the end face runout of the grinding wheel is not more than 0.05 mm, the rotational speed of the grinding wheel is (320 ± 5) r / min, the grinding track is annular, the inner diameter is 87 ± 0.2 mm, and the ring width is 16.5 ± 0.4 mm; the grinding pressure is constant at 15 N. (Dry grinding, the mesh number of the abrasive sample is fixed at 120)

[0066] Test steps: Weigh the sample after placing it in the atmospheric condition for 24 hours, place it on the grinding wheel of the grinding performance tester, start timing for 30 min after applying a constant grinding pressure, and then weigh the ground sample bar (aluminum bar) and the sample respectively. The amount of metal removed and the amount of abrasive shedding of the sample are obtained by calculating the mass difference before and after grinding.

[0067] Example 1

[0068] A preparation method of a new type of ceramic abrasive is as follows:

[0069] (1) Preparation of the composite secondary seed: Boehmite is used as the main raw material to make a gel, and after aging, a composite additive MgO-CaO-SiO 2(2.5 wt.%, molar ratio 5:1:5) and α-Al 2 O 3 (3.0 wt.%). The mixture was ball-milled for 2 h (rotation speed set at 250 r / min) with absolute alcohol as the medium, and after drying (80 °C, 15 h), it was crushed and classified. Particles between 80 / 100 mesh were selected for atmospheric pressure sintering (rapidly heated to 1350 °C at a rate of 5 °C / min and then cooled to 1150 °C for heat preservation for 5 h). After sintering, the composite secondary seed was obtained for standby.

[0070] (2) Preparation of abrasive gel: Using pseudo-boehmite as the main material, PEG1000 (1 wt.%) was added to prepare a suspension with a solid content of 35%. After fully stirring in a 60 °C water bath environment for 15 min, 1 mol / L HNO 3 was added to adjust the pH of the system to 2.5 - 2.8. After repeating the water bath stirring for 1 h, it was aged at room temperature for 24 h.

[0071] (3) Preparation of abrasive precursor: The aged gel was washed 3 times with deionized water, and the composite additive MgO-TiO 2 -SiO 2 (2.0 wt.%, molar ratio 3:5:11) and the composite secondary seed (2.0 wt.%) were introduced. It was ball-milled for 2 h (rotation speed set at 250 r / min) with absolute alcohol as the medium, and then the obtained slurry was dried (80 °C, 15 h).

[0072] (4) Abrasive sintering: The dried block was crushed and placed in a sintering furnace for atmospheric pressure sintering. Two-step staged heat preservation sintering was adopted during sintering. At the initial stage of sintering, it was rapidly heated to 1350 °C at a rate of 5 °C / min, then the sintering temperature was reduced to 1050 °C for heat preservation for 1 h, and then cooled to 950 °C for heat preservation for 4 h.

[0073] Examples 2 - 4

[0074] A preparation method of a novel ceramic abrasive. The preparation process is basically the same as that of Example 1, except that the addition amounts of the composite secondary seeds in the preparation of the abrasive precursor in Step 3 are 2.5 wt.%, 3.0 wt.%, and 3.5 wt.% respectively.

[0075] Comparative Example 1

[0076] A preparation method of a novel ceramic abrasive. The preparation process is basically the same as that of Example 1, except that there is no preparation of the composite secondary seed, and the seed material added in the preparation of the abrasive precursor in Step 3 is α-Al 2 O 3 (3.0 wt.%).

[0077] The performance parameters of the abrasives obtained in Examples 1-4 and Comparative Example 1, such as single-particle compressive strength, relative density, hardness, and fracture toughness, were tested, and the results are shown in the appendix Figure 2 , appendix Figure 3 and Table 1 as follows:

[0078] Table 1 Comparison of various performances of abrasives obtained in Examples 1-4 and Comparative Example 1

[0079]

[0080] From the above test results, it can be seen that in Comparative Example 1 with conventional seeds added, the performance of the abrasive in all aspects lags behind that of each example with composite secondary seeds added. The main reasons are as follows: ① MgO-CaO-SiO 2 The multiphase additive is a classic ceramic corundum small grain auxiliary additive system, which can well guide the formation of homogeneous grains below 100 nanometers (as can be seen from the appendix Figure 4 ). By pre-preparing homogeneous small grains as seeds and introducing them into the subsequent abrasive preparation process, it can well reduce the α-Al 2 O 3 phase transformation temperature, and through its own homogeneous fine grains as nucleation guidance, induce the subsequent abrasive to grow into a dense fine grain morphology; although adding a single α-Al 2 O 3 as a seed can also play a similar role, the role of the composite secondary seed is more intense and effective. Compared with the single α-Al 2 O 3 seed, MgO, CaO, and SiO 2 can significantly inhibit the abnormal growth of alumina grains and easily form a micro-liquid phase at the grain boundary to accelerate the densification rate during sintering. ② Although in the subsequent preparation process, in addition to the additive components carried by the seeds, additives of the MgO-TiO 2 -SiO 2 system were also added, but in addition to the different compositions, the two systems have great differences in the role of grain forming and growth; it is precisely through the introduction of secondary seeds that the influence of additives in different systems can be more simply and accurately controlled during the preparation process. If MgO, CaO, SiO 2、 TiO 2 are directly added as additives in the same system, it will greatly increase the complexity of the system reaction, and the optimization of the addition amount and molar ratio of this additive system will be a very complex and difficult-to-control task; ③ The above two additive systems can better avoid their respective adverse effects and give full play to their own favorable effects by using different addition methods. In the initial stage of rapid sintering temperature rise, due to the guidance of the composite secondary seed, as well as MgO, CaO, and SiO 2Under the influence of several additives, a large number of tiny homogeneous grains are formed rapidly, and the densification rate of the whole system is accelerated. When the grain boundaries for rapid growth between grains become more and more obvious, the sintering enters the heat preservation stage at a lower temperature, mainly in MgO-TiO 2 -SiO 2 Under the influence of the additive system, the growth rates of a small number of alumina grains on different crystal planes are differentiated, and they grow anisotropically and rapidly through the small voids between grains, forming an interlocked grain structure between grains of different morphologies, making the whole system more dense. ④ It can be seen from the test results that the lower fracture toughness of the comparative example is more prominent compared with other performance parameters. This is because when the comparative example has no guiding effect of the composite secondary seed, it only relies on MgO-TiO 2 -SiO 2 Although the additive system can enhance the toughness of the abrasive to a certain extent, without the strong induction effect of the secondary seed in the early stage, under the influence of subsequent additives, more grains of alumina will grow anisotropically. Especially, some flaky grains formed without induction constraints will grow rapidly in the thickness direction, increasing the voids between grains and unable to form a relatively dense grain interlocked structure. Attached Figure 5 The intuitive comparison shows the difference in microstructure between Comparative Example 1 (left figure) and Example 2 (right figure).

[0081] Examples 5-6

[0082] A preparation method of a new type of ceramic abrasive, the preparation process is basically the same as that of Example 2, the difference is that the first temperature reduction during sintering reaches 1150°C and 1250°C respectively.

[0083] Comparative Example 2

[0084] A preparation method of a new type of ceramic abrasive, the preparation process is basically the same as that of Example 2, the difference is that after the sintering is rapidly heated to 1350°C, it is directly cooled to 950°C and kept warm for 5h.

[0085] According to the summary of the kinetic law of the ceramic corundum abrasive (with additives) system under sintering, when the temperature is higher than 1250°C, the requirement of the relative density greater than 75% can be achieved for the system. When the temperature is raised to about 1350°C, the rapid densification of the system can be realized, and at the same time, the grain size will not be increased too much. Therefore, the initial sintering temperature of the present invention is fixed at 1350°C, and the composite secondary seed system can reduce the lowest temperature required for the grain boundary diffusion effect of the system. Therefore, the lowest temperature for heat preservation is fixed at 950°C. The test is carried out for comparing the intermediate temperature of the first temperature reduction, and the test results are shown in Table 2, attached Figure 6 and attached Figure 7 as shown:[[]]

[0086] Table 2 Comparison of various properties of abrasives obtained in Examples 2, 5, 6 and Comparative Example 2

[0087]

[0088]

[0089] Based on the above test results, it can be seen that setting the intermediate heat preservation temperature at 1150 °C can obtain ceramic corundum abrasives with better comprehensive performance. Although the performance parameters of Comparative Example 2 in terms of single-particle compressive strength, relative density and hardness have reached a quite high level, its fracture toughness is much lower than that of Example 5. This is exactly the significance of setting the intermediate heat preservation step. The conventional two-step sintering method is to first heat the material to a relatively high temperature to obtain a thermodynamic driving force sufficient for grain boundary diffusion in the system, and then quickly cool it to a relatively low temperature and continue to keep it warm, so as to inhibit grain boundary migration and fully remove pores by the diffusion of grain boundaries to make the material densify. Its application to a general ceramic corundum abrasive (with additives) system can achieve a good sintering effect. However, the additive system established in the present invention is a system with composite secondary seeds. During the initial heating and sintering, in addition to inducing the rapid formation of fine grains, the composite secondary seeds will also form a continuous liquid phase to fill between the grains, effectively inhibiting abnormal grain growth as the second phase of the grain boundary. At this time, it is necessary to keep it warm at a relatively high temperature for a period of time to provide the energy for the anisotropic continuous growth of a small number of alumina grains in the grain voids, so that a better grain system with interlocked different morphological structures will be formed in the final heat preservation stage, further enhancing the apparent fracture toughness of the whole. However, it can be found from Example 6 that too high an intermediate heat preservation temperature will over-stimulate the growth of other grains, resulting in voids between the grains, thus reducing the denseness of the overall structure and leading to a decline in performance.

[0090] Example 7

[0091] A preparation method of a new type of ceramic abrasive dry sandpaper, the main technological process including substrate treatment → applying primer → sand planting → pre-drying → applying sizing agent → applying anti-blocking coating → drying → winding → humidifying → parking → finished product.

[0092] Among them, the base material is made of a composite base material composed of flexible latex paper and a PET film. The base material treatment steps include base material flexibility detection and surface leveling treatment; the binder of the base glue is a flexible resin such as epoxy resin and polyurethane resin; the abrasive used in the sand planting step is a mixture of a new material abrasive made in Example 5 and a common abrasive. The specific treatment method is to classify the ceramic corundum abrasive, screen out the first 1 / 3 - 1 / 2 of the particle size and mix it with the common abrasive in a ratio of 30% - 50%. The sand planting adopts a low-density sand planting process; the compound glue is added with a thermosetting novolac resin (solid content 60% - 80%), 5% - 20% NBR, acrylic emulsion and 0.5% - 2% antistatic agent.

[0093] Comparative Example 3

[0094] A preparation method of a new type of ceramic abrasive dry sandpaper, the main process flow and treatment process are the same as those in Example 7, except that the ceramic corundum abrasive used in sand planting adopts the preparation material formula of Comparative Example 1.

[0095] Comparative Example 4

[0096] A preparation method of a new type of ceramic abrasive dry sandpaper, the main process flow and treatment process are the same as those in Example 7, except that the ceramic corundum abrasive used in sand planting adopts the sintering temperature scheme of Comparative Example 2.

[0097] Comparative Example 5

[0098] A preparation method of a new type of ceramic abrasive dry sandpaper, the main process flow and treatment process are the same as those in Example 7, except that the sand planting density is maintained at a normal density for implantation.

[0099] Comparative Example 6

[0100] A preparation method of a new type of ceramic abrasive dry sandpaper, the main process flow and treatment process are the same as those in Example 7, except that no antistatic agent is added to the compound glue.

[0101] Comparative Example 7

[0102] A preparation method of a new type of ceramic abrasive dry sandpaper, the main process flow and treatment process are the same as those in Example 7, except that no anti-blocking coating is applied.

[0103] Test the grinding performance of the samples of Example 7 and Comparative Examples 3 - 7, and the results are shown in Table 3:

[0104]

[0105] Based on the above results, it can be seen that in Comparative Examples 3 and 4, due to the differences in the formula and method during the abrasive preparation stage, the performance of the abrasive itself in various aspects is relatively low. In particular, the low fracture toughness leads to certain impacts on the grinding efficiency, material retention, and service life after the abrasive is made into a grinding tool. In Comparative Examples 5, 6, and 7, the omission of key steps in the grinding tool also reduces the performance of the grinding tool to a certain extent. Although the material removal amount in Comparative Example 5 is large, it does not adopt the process of low-density abrasive implantation, resulting in an increase in the amount of abrasive shedding, and its material removal amount does not increase much. From this, it can be seen that low-density abrasive implantation reduces the loss of the sample abrasive while ensuring the material removal amount. Comparative Examples 6 and 7 prove the advantages of the antistatic agent and the anti-blocking coating. The grinding tool sample prepared in Example 7 with comprehensive favorable parameters realizes high grinding efficiency and low loss rate through the improvement of abrasive preparation and grinding tool preparation. Among them, the new abrasive material has good self-sharpening property, low loss rate, small heat generation, and high hardness, and is suitable for the application scenario of precision grinding. In addition, the grinding tool made of it has a low amount of abrasive shedding, will not cause process blockage, abnormal heat generation, and efficiency reduction.

Claims

1. A method for preparing a novel ceramic abrasive, characterized in that: The preparation formula of the novel ceramic abrasive comprises a composite seed crystal and a composite additive, and the novel ceramic abrasive adopts a two-step sintering process in the sintering stage.

2. The method for preparing the novel ceramic abrasive according to claim 1, characterized in that: The steps include: Step 1, preparing composite seed crystals, using alumina hydrate as the main raw material to make gel, then introducing a composite additive consisting of metal oxide and SiO2 into the aged gel to form a mixture, ball-milling the mixture and drying it, then crushing and grading it, and selecting particles with a certain range of mesh sizes for sintering to obtain composite seed crystals; Step 2: prepare abrasive gel, use alumina hydrate as the main raw material, add a dispersant to prepare a suspension, stir thoroughly in a water bath, add acid to adjust the pH to an appropriate range, repeat the water bath stirring, and age at room temperature; Step 3, preparing an abrasive precursor, washing the gel obtained in step 2 with deionized water, adding a composite additive consisting of metal oxide and SiO2, and then adding the composite seed crystal prepared in step 1, ball-milling the mixture and drying it; Step 4: abrasive sintering. The abrasive precursor obtained in step 3 is crushed and placed in a sintering furnace for normal pressure sintering. The sintering is divided into two stages: rapid heating and fixed temperature insulation.

3. The method for preparing the novel ceramic abrasive according to claim 2, characterized in that: The composite seed crystal described in step 1 is a composite secondary seed crystal; The alumina hydrate in step 1 is at least one of pseudo-boehmite, aluminum hydroxide, boehmite or boehmite; The metal oxides in step 1 are MgO, CaO and α-Al2O3, the addition amount of MgO-CaO-SiO2 is 2.5wt.%, the molar ratio is 5:1:5, and the addition amount of α-Al2O3 is 3.0wt.%; The particles with a certain range of mesh sizes described in step 1 have a mesh size range of 60-120 meshes.

4. The method for preparing the novel ceramic abrasive according to claim 2, characterized in that: The alumina hydrate in step 2 is at least one of pseudo-boehmite, aluminum hydroxide, boehmite or boehmite; The dispersant in step 2 is at least one of ammonium citrate, ammonium polyacrylate or PEG; The pH adjusting acid in step 2 is HNO 3、 Citric acid 、 At least one of hydrochloric acid; The appropriate pH range described in step 2 is 2-3.

5. The method for preparing the novel ceramic abrasive according to claim 2, characterized in that: The metal oxides in step 3 are MgO and TiO2, and the addition amount of MgO-TiO2-SiO2 is 2.0wt.%, and the molar ratio is 3:5:11; The addition amount of the composite seed crystal prepared in step 1 described in step 3 is 2.0wt.%-3.5wt.%.

6. The method for preparing the novel ceramic abrasive according to claim 2, characterized in that: The rapid heating rate of step 4 is 5°C / min, and the final temperature after heating is 1350°C; The fixed temperature insulation stage described in step 4 includes a first stage and a second stage.

7. The method for preparing the novel ceramic abrasive according to claim 6, characterized in that: The insulation temperature of the first stage is 1050°C-1250°C, and the insulation time is 1 hour. The insulation temperature of the second stage is 950°C, and the insulation time is 4 hours.

8. A method for preparing a novel ceramic abrasive dry sandpaper, characterized in that: The novel ceramic abrasive comprises the novel ceramic abrasive according to any one of claims 1 to 7.

9. The method for preparing the novel ceramic abrasive dry sandpaper according to claim 8, characterized in that: The following steps are involved: Substrate treatment → primer application → sand planting → pre-drying → re-glue application → anti-blocking coating application → drying → winding → rehumidification → parking → finished product.

10. The method for preparing the novel ceramic abrasive dry sandpaper according to claim 9, characterized in that: The substrate is made of a composite substrate made of flexible latex paper and PET film, and the substrate processing step includes substrate flexibility detection and surface flattening treatment; The adhesive of the base glue is a flexible resin; The sand planting adopts a low-density sand planting process. In the sand planting step, the new ceramic abrasive is graded, and the first 1 / 3-1 / 2 of the particle size is screened out and mixed with ordinary abrasive in a ratio of 30% to 50%; Thermosetting resol phenolic resin, NBR, acrylic emulsion and antistatic agent are added into the composite adhesive.

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