Thickness-controlled material, preparation method, application and silicon carbide honeycomb ceramic

Abstract

The present invention relates to the technical field of honeycomb ceramics, and in particular, to a thickness control material, a preparation method, an application, and a silicon carbide honeycomb ceramic. The components of the thickness control material include silicon carbide powder, hydroxypropyl methylcellulose, redispersible latex powder, inorganic sol, water, and a lubricant; the silicon carbide powder includes coarse-grained powder and fine-grained powder, and the particle size D of the coarse-grained powder 50 is 20-30 μm, and the particle size D of the fine-grained powder 50 is 1-2 μm. The thickness control material can be used to prepare a silicon carbide honeycomb ceramic. The thickness control mud has appropriate rigidity, good thickness consistency, and a thermal conductivity closer to that of the silicon carbide honeycomb ceramic unit block, enabling the silicon carbide honeycomb ceramic to have excellent thermal shock resistance; the silicon carbide honeycomb ceramic has good control over the thickness of the splicing mud, stable back pressure, and good thermal shock resistance.

Description

Technical Field

[0001] The invention relates to the technical field of honeycomb ceramics, and in particular to a thickness-controlled material, a preparation method, an application and a silicon carbide honeycomb ceramic. Background Art

[0002] Air pollution seriously affects people's health and quality of life. Wall-flow honeycomb ceramics become particulate collectors. For particulate collectors used in most light and medium-sized diesel engines, due to volume limitations and high carbon load requirements, silicon carbide honeycomb ceramics are generally used to avoid melting of materials during regeneration. However, due to the high thermal expansion coefficient, high thermal stress, and poor thermal shock resistance of silicon carbide, particulate collectors are generally made by splicing. Usually, rectangular unit blocks are prepared first, and then the unit blocks are glued together by splicing mud to form 4×4, 5×5, 6×6, 7×7, 8×8 and other large rectangular blocks, and then machined into cylinders, and then skinned and heat treated to obtain silicon carbide honeycomb ceramic particulate collectors.

[0003] If the thickness of the splicing mud is too small, the bonding strength of the silicon carbide particle collector will be insufficient and the ability to buffer thermal stress will be insufficient, which will lead to poor thermal shock and easy cracking. If the thickness of the splicing mud is too thick, it will lead to reduced filtration area and increased back pressure. Uneven thickness of the splicing mud will lead to back pressure fluctuations and uneven heat distribution, which may further lead to excessive local temperature differences and thermal shock cracking. Therefore, it is very important to control the thickness of the splicing mud.

[0004] The existing technology does not use thickness control materials, or uses silica sol impregnated ceramic fiber sheets. The material of the ceramic fiber sheets is very different from that of the silicon carbide unit blocks and the splicing mud, and the thermal conductivity coefficient is quite different. During use, a large temperature difference will be generated, which is easy to crack. In addition, the ceramic fiber sheets will expand and deform during the impregnation process, and the thickness consistency is poor. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a thickness-controlled material, a preparation method, an application and a silicon carbide honeycomb ceramic.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] The present invention provides a thickness control material, wherein the thickness control material comprises silicon carbide powder, hydroxypropyl methylcellulose, redispersible latex powder, inorganic sol, water and lubricant; the silicon carbide powder comprises coarse-grained powder and fine-grained powder, and the particle size D of the coarse-grained powder is 50 The particle size D of the fine-grained powder is 20-30 μm. 50 1-2μm.

[0008] Based on the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, in the silicon carbide powder, the mass percentage of coarse-grained powder is 85wt%-95wt%, and the balance is the fine-grained powder.

[0010] Furthermore, the silicon carbide powder is a cooked powder, the chemical composition of the cooked powder is consistent with that of the silicon carbide honeycomb ceramic unit block, and the mass percentage of silicon carbide in the cooked powder is greater than or equal to 60%.

[0011] Furthermore, the inorganic sol is one or more of silica sol, aluminum sol and zirconium sol.

[0012] Furthermore, the lubricant is one or more of soybean oil, tung oil, white oil, and industrial butter.

[0013] Furthermore, in the thickness control material, the mass ratio of the silicon carbide powder, the hydroxypropyl methylcellulose, the redispersible latex powder, the inorganic sol, water, and the lubricant is 100:1-2:0.5-1.5:10-20:5-10:2-5.

[0014] Furthermore, the thickness-controlled material is cylindrical, and has a cross-sectional diameter of 1-2 mm.

[0015] The present invention also provides a method for preparing the thickness control material as described above, comprising mixing the silicon carbide powder and the hydroxypropyl methylcellulose to obtain a solid mixture; mixing the redispersible latex powder, the inorganic sol and water to obtain a liquid mixture; adding the liquid mixture to the solid mixture, kneading and adding the lubricant, kneading again, and sequentially performing mud kneading, aging, extrusion molding, drying and cutting to obtain the thickness control material.

[0016] The present invention also provides an application of the thickness-controlled material as described above, which is used for preparing silicon carbide honeycomb ceramics.

[0017] The present invention also provides a silicon carbide honeycomb ceramic, which includes a plurality of silicon carbide honeycomb ceramic unit blocks, two side walls of adjacent silicon carbide honeycomb ceramic unit blocks are connected and fixed by splicing mud, and the thickness control material as mentioned above is provided between the two side walls.

[0018] The beneficial effects of the present invention are:

[0019] (1) The thickness-controlled mud material of the present invention has suitable rigidity, good thickness consistency, and a thermal conductivity coefficient that is closer to that of the silicon carbide honeycomb ceramic unit block, which can make the silicon carbide honeycomb ceramic have excellent thermal shock resistance;

[0020] (2) The thickness control mud material of the present invention includes coarse-grained powder material and fine-grained powder material. The reasonable combination of the two makes the thickness control material easy to extrude and maintain strong rigidity;

[0021] (3) The thickness control mud material of the present invention, hydroxypropyl methylcellulose and lubricant make the thickness control material have good plasticity, the inorganic sol has a certain rigidity after drying, and the redispersible latex powder forms a polymer film in the thickness control material. The polymer film will not disperse again after contacting water, thereby preventing the invasion of water. The thickness control material can be used directly after drying without sintering, and will not be soaked by the splicing mud, thereby reducing the rigidity and losing the thickness control effect;

[0022] (4) Compared with ceramic fiber sheets, the silicon carbide honeycomb ceramic of the present invention can be directly placed on the unit block coated with splicing mud using a cylindrical thickness control material, because the columnar shape can easily squeeze the splicing mud to the side, while the ceramic fiber sheet needs to be glued to the unit block in advance, otherwise it is easy to overflow with excess splicing mud during the extrusion process. Because there is no need to use an additional adhesive to bond the thickness control material to the silicon carbide unit block, the bonding efficiency can be effectively improved;

[0023] (5) The silicon carbide honeycomb ceramic of the present invention has good control effect on the thickness of the splicing mud, stable back pressure, and good thermal shock resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the connection structure between two adjacent silicon carbide unit blocks in the silicon carbide honeycomb ceramic of the present invention;

[0025] Figure 2 It is a schematic diagram of the preparation structure of the silicon carbide honeycomb ceramic of the present invention.

[0026] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0027] 1. L-shaped board; 2. Splicing bracket; 3. Splicing mud; 4. Thickness-controlled material; 5. Flat plate. DETAILED DESCRIPTION

[0028] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0029] The thickness control material of the present invention comprises silicon carbide powder, hydroxypropyl methylcellulose, redispersible latex powder, inorganic sol, water and lubricant; the silicon carbide powder comprises coarse-grained powder and fine-grained powder, and the particle size of the coarse-grained powder is D 50 The particle size D of fine powder is 20-30μm. 50 1-2μm.

[0030] The thickness control material of the present invention has certain rigidity, good thickness consistency, and a thermal conductivity coefficient that is closer to that of the unit block. The silicon carbide honeycomb ceramic splicing mud spliced ​​using the thickness control material has good thickness consistency and excellent heat shock resistance. The reasonable combination of coarse-grained powder and fine-grained powder makes the thickness control material easy to extrude and maintain strong rigidity. Hydroxypropyl methylcellulose and lubricants can make the thickness control material have good plasticity and be easy to extrude and form. Adding inorganic sol has certain rigidity after drying. Adding redispersible latex powder to the thickness control material forms a polymer film. The polymer film will not disperse again after encountering water, thereby preventing the invasion of water. The thickness control material does not need to be sintered after drying and can be used directly without being soaked by the splicing mud, thereby weakening the rigidity and losing the thickness control effect.

[0031] It should be noted that the D of the raw materials used in the present invention is 50 D refers to the cumulative distribution of the raw material 50 .

[0032] Preferably, in the silicon carbide powder, the mass percentage of the coarse-grained powder is 85wt%-95wt%, and the remainder is the fine-grained powder.

[0033] The silicon carbide powder of the present invention has a wide range of sources. Specifically, it can be the recycled powder of silicon carbide honeycomb ceramics such as silicon-bonded silicon carbide honeycomb ceramics, oxide-bonded silicon carbide honeycomb ceramics, recrystallized silicon carbide honeycomb ceramics, etc. The recycled powder of silicon carbide honeycomb ceramics is made by crushing and grinding the waste products such as scraps and unqualified products generated by the grinding of silicon carbide honeycomb ceramics, and the mass percentage of silicon carbide is greater than or equal to 60%.

[0034] The silicon carbide honeycomb ceramic recycled powder has a thermal conductivity and thermal expansion coefficient that is closer to that of the silicon carbide honeycomb ceramic unit block and splicing mud, has better thermal shock resistance, can effectively reduce the cost of thickness control materials, and can also achieve waste recycling.

[0035] Preferably, the inorganic sol is one or more of silica sol, aluminum sol and zirconium sol.

[0036] More preferably, the inorganic sol is silica sol.

[0037] Preferably, the lubricant is one or more of soybean oil, tung oil, white oil, and industrial butter.

[0038] More preferably, the lubricant is white oil.

[0039] Preferably, in the thickness control material, the mass ratio of silicon carbide powder, hydroxypropyl methylcellulose, redispersible latex powder, inorganic sol, water, and lubricant is 100:1-2:0.5-1.5:10-20:5-10:2-5.

[0040] Further preferably, in the thickness control material, the mass ratio of silicon carbide powder, hydroxypropyl methylcellulose, redispersible latex powder, inorganic sol, water and lubricant is 100:1:1:15:8:2.

[0041] Preferably, the thickness control material is cylindrical with a cross-sectional diameter of 1-2 mm. If the diameter is too large, the thickness of the splicing mud will be too thick, resulting in a reduced filtration area, increased back pressure, etc. If the diameter is too small, the thickness of the splicing mud will be too small, resulting in poor bonding effect and poor thermal stress buffering effect, and easy cracking during thermal shock.

[0042] Further preferably, the cross-sectional diameter is 1.3-1.5 mm.

[0043] Preferably, the length of the thickness control material is 10-16 mm smaller than the width of the unit block. If it is too long, the bonding strength will be affected, while if it is too short, it will not be able to support well during extrusion and affect the thickness control effect.

[0044] The preparation method of the thickness control material of the present invention comprises the following steps: mixing silicon carbide powder and hydroxypropyl methylcellulose to obtain a solid mixture; mixing redispersible latex powder, inorganic sol and water to obtain a liquid mixture; adding the liquid mixture to the solid mixture, kneading and adding a lubricant, kneading again, and sequentially performing mud kneading, aging, extrusion molding, drying and cutting to obtain the thickness control material.

[0045] Preferably, the lubricant is added after kneading for 10 minutes, and kneading is continued for another 5 minutes.

[0046] The silicon carbide honeycomb ceramic of the present invention comprises a plurality of silicon carbide honeycomb ceramic unit blocks, two side walls of adjacent silicon carbide honeycomb ceramic unit blocks are connected and fixed by splicing mud, and the thickness control material of the present invention is arranged between the two side walls.

[0047] Preferably, the plurality of silicon carbide unit blocks are fixed by splicing mud.

[0048] The specific preparation process of the silicon carbide honeycomb ceramic of the present invention is as follows:

[0049] like Figure 1~2 As shown, an L-shaped plate 1 is placed on a splicing bracket 2, a silicon carbide honeycomb ceramic unit block A is placed on the L-shaped plate 1, a layer of splicing mud 3 is applied, and then a thickness control material 4 is placed at the center and 10-15mm away from both ends, and the excess mud is squeezed to overflow.

[0050] Splice a plurality of silicon carbide honeycomb ceramic unit blocks in the order of A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, or in the order of A, F, K, P, U, B, G, L, Q, V, C, H, M, R, W, D, I, N, S, X, E, J, O, T, Y, and then place two flat plates 5 on the two side surfaces and squeeze them so that excess mud overflows from the end surface, and then dry, grind the end surface, round it, graft the skin, and perform heat treatment.

[0051] Compared with ceramic fiber sheets, the silicon carbide honeycomb ceramic of the present invention uses a cylindrical thickness control material that can be directly placed on a silicon carbide honeycomb ceramic unit block coated with splicing mud, because the columnar shape can easily squeeze the splicing mud to the side, while the ceramic fiber sheet needs to be glued to the unit block in advance, otherwise it is easy to overflow with excess splicing mud during the extrusion process. Because there is no need to use an additional adhesive to bond the thickness control material to the silicon carbide honeycomb ceramic unit block, the bonding efficiency can be effectively improved.

[0052] Because the thickness control material has good consistency and certain rigidity, the thickness control effect of the silicon carbide honeycomb ceramic splicing mud is good, the back pressure is stable, and the thermal shock resistance is good.

[0053] The present invention is illustrated below by means of specific examples.

[0054] In the following embodiments, D 50 The measurement was carried out using the laser diffraction principle, using the LS-609 instrument from OMEC.

[0055] The silicon carbide unit block used in the following embodiments and comparative examples has a width of 39.5 mm, a height of 156 mm, a wall thickness of 9 mils, a pore density of 300 mesh, and is made of silicon-bonded silicon carbide. A 190.5×152.4-300 / 9 silicon-bonded silicon carbide honeycomb ceramic is prepared in a 5×5 manner. Of course, the size of the unit block and the diameter, height, pore density and wall thickness of the honeycomb ceramic and the splicing method are not limited to this, and the material is not limited to this, and it can also be oxide-bonded silicon carbide or recrystallized silicon carbide.

[0056] Example 1

[0057] The mud material preparation process of this embodiment is as follows:

[0058] Step 1: Weigh the silicon carbide honeycomb ceramic cooked green powder according to mass fraction, among which the D 50 The particle size of the fine-grained powder is 25 μm, the mass percentage is 85%, and the D 50 The particle size is 1 μm and the mass percentage is 15%.

[0059] At the same time, based on 100 parts by weight of the silicon carbide honeycomb ceramic cooked green powder, 1 part by weight of hydroxypropyl methylcellulose was weighed, and the dry powder was evenly mixed to obtain a solid mixture.

[0060] Step 2: Based on 100 parts by weight of the silicon carbide honeycomb ceramic cooked green powder, weigh 1 part by weight of redispersible latex powder, 15 parts by weight of silica sol, and 8 parts by weight of water, mix the three and disperse them at high speed to obtain a liquid mixture. In addition, weigh 2 parts by weight of white oil for later use.

[0061] Step 3: Add the liquid mixture to the solid mixture, knead for 10 minutes, then add the weighed white oil, continue kneading for 5 minutes, and then carry out mud kneading, aging, extrusion molding, drying, and cutting in sequence to obtain a controlled thickness material.

[0062] Step 4: Figure 1~2 As shown, an L-shaped plate 1 is placed on a splicing bracket 2, a silicon carbide honeycomb ceramic unit block A is placed on the L-shaped plate 1, a layer of splicing mud 3 is applied, and then a thickness control material 4 with a diameter of 1.3 mm and a length of 27.5 mm is placed at the center and 10-15 mm away from both ends, and the excess mud is squeezed to overflow, and the unit blocks A, F, K, P, U, B, G, L, Q, V, C, H, M, R, W, D, I, N, S, X, E, J, O, T, and Y are spliced ​​in the order, and then two flat plates 2 are placed on the two sides and squeezed to make the excess mud overflow from the end faces, and then the silicon carbide honeycomb ceramic with thickness control material is obtained by drying, grinding the end faces, rounding, skin grafting, and heat treatment.

[0063] Example 2

[0064] The preparation process of this embodiment is the same as that of embodiment 1, except that in step 1, the mass percentage of the coarse-grained powder in the silicon carbide honeycomb ceramic recycled powder is 90%, and the mass percentage of the fine-grained powder is 10%.

[0065] Example 3

[0066] The preparation process of this embodiment is the same as that of embodiment 1, except that in step 1, the mass percentage of the coarse-grained powder in the silicon carbide honeycomb ceramic recycled powder is 95%, and the mass percentage of the fine-grained powder is 5%.

[0067] Example 4

[0068] The preparation process of this embodiment is the same as that of embodiment 2, except that in step 1, the coarse-grained powder of the silicon carbide honeycomb ceramic is 50 D of fine-grained powder is 20 μm 50 is 2μm.

[0069] Example 5

[0070] The preparation process of this embodiment is the same as that of embodiment 4, except that in step 1, the D of the coarse-grained powder in the silicon carbide honeycomb ceramic cooked green powder is 50 is 25μm.

[0071] Example 6

[0072] The preparation process of this embodiment is the same as that of embodiment 4, except that in step 1, the coarse-grained powder of the silicon carbide honeycomb ceramic is 50 is 30μm.

[0073] Example 7

[0074] The preparation process of this embodiment is the same as that of embodiment 2, except that in step 1, the fine-grained powder of the silicon carbide honeycomb ceramic is 50 is 1.5μm.

[0075] Example 8

[0076] The preparation process of this embodiment is the same as that of Example 7, except that in step 1, the amount of hydroxypropyl methylcellulose is 1.5 parts by weight.

[0077] Example 9

[0078] The preparation process of this embodiment is the same as that of Example 7, except that in step 1, the amount of hydroxypropyl methylcellulose is 2 parts by weight.

[0079] Example 10

[0080] The preparation process of this embodiment is the same as that of Embodiment 8, except that the redispersible latex powder in step 2 is 0.5 parts by weight.

[0081] Embodiment 11

[0082] The preparation process of this embodiment is the same as that of Embodiment 8, except that the redispersible latex powder in step 2 is 2 parts by weight.

[0083] Example 12

[0084] The preparation process of this embodiment is the same as that of Embodiment 8, except that the sol in step 2 is aluminum sol.

[0085] Example 13

[0086] The preparation process of this embodiment is the same as that of Embodiment 8, except that the sol in step 2 is zirconium sol.

[0087] Embodiment 14

[0088] The preparation process of this embodiment is the same as that of Embodiment 8, except that in step 2, the amount of silica sol is 10 parts by weight and the amount of water is 10 parts by weight.

[0089] Embodiment 15

[0090] The preparation process of this embodiment is the same as that of Embodiment 8, except that in step 2, the amount of silica sol is 20 parts by weight and the amount of water is 5 parts by weight.

[0091] Example 16

[0092] The preparation process of this embodiment is the same as that of Example 8, except that the amount of white oil in step 2 is 3.5 parts by weight.

[0093] Embodiment 17

[0094] The preparation process of this embodiment is the same as that of Embodiment 8, except that the amount of white oil in step 2 is 5 parts by weight.

[0095] Embodiment 18

[0096] The preparation process of this embodiment is the same as that of Example 16, except that the lubricant in step 2 is soybean oil.

[0097] Embodiment 19

[0098] The preparation process of this embodiment is the same as that of Example 16, except that the lubricant in step 2 is tung oil.

[0099] Embodiment 20

[0100] The preparation process of this embodiment is the same as that of Example 16, except that the lubricant in step 2 is industrial butter.

[0101] Embodiment 21

[0102] The preparation process of this embodiment is the same as that of Embodiment 16, except that the diameter of the thickness-controlled material in step 3 is 1 mm.

[0103] Embodiment 22

[0104] The preparation process of this embodiment is the same as that of Embodiment 16, except that the diameter of the thickness-controlled material in step 3 is 1.5 mm.

[0105] Embodiment 23

[0106] The preparation process of this embodiment is the same as that of Embodiment 16, except that the diameter of the thickness-controlled material in step 3 is 2 mm.

[0107] Embodiment 24

[0108] The preparation process of this embodiment is the same as that of Embodiment 16, except that the length of the thickness-controlled material in step 3 is 24.5 mm.

[0109] Embodiment 25

[0110] The preparation process of this embodiment is the same as that of Embodiment 16, except that the length of the thickness-controlled material in step 3 is 29.5 mm.

[0111] Comparative Example 1

[0112] The manufacturing process of the silicon carbide honeycomb ceramic in this comparative example is the same as that in Example 1, except that no thickness control material is used in this comparative example.

[0113] Comparative Example 2

[0114] The manufacturing process of the silicon carbide honeycomb ceramic in this comparative example is the same as that in Example 1, with the only difference being that a ceramic fiber sheet with a thickness of 1.2 and impregnated with silica sol is used as a thickness control material in this comparative example.

[0115] Comparative Example 3

[0116] The preparation process of the thickness control material and the silicon carbide honeycomb ceramic in this comparative example is the same as that in Example 16, with the only difference being that no redispersible latex powder is added during the preparation of the thickness control material.

[0117] The following evaluations were performed on the above-mentioned Examples and Comparative Examples.

[0118] (1) The samples with a size of 25 mm × 25 mm × 25 mm prepared in each embodiment and comparative example were tested for compressive strength of the controlled thickness material using a microcomputer-controlled electronic pressure testing machine produced by Jinan Zhongchuang Industrial Testing System Co., Ltd. The compressive strength of the water-immersed material was tested again after being soaked in water for 30 minutes.

[0119] (2) Use an image measuring instrument to measure the thickness of the joint mud between adjacent unit blocks, record the value, and calculate the average and range.

[0120] (3) The flow rate is tested using the Super-Flow1020 back pressure tester at 600 Nm 3 / h back pressure value.

[0121] (4) Place the silicon carbide honeycomb ceramic in an electric furnace maintained at the specified temperature and conduct a thermal shock test. Raise the furnace temperature to 400°C at a heating rate of no more than 6°C / min, and place the sample in the furnace without contact with each other. After heating to the set temperature, keep warm for 30 minutes, open the furnace door, take out the sample, and cool it naturally to room temperature in the air. Perform three cycles on the sample. After each thermal cycle, observe whether the product is cracked using a water mist laser detection device. If there is no cracking after three cycles, continue to increase the detection temperature by 50°C each time. Until cracking occurs after three cycles, the temperature below this test temperature is recorded as the thermal shock temperature.

[0122] The products obtained in the above examples and comparative examples were subjected to performance tests, and the results are shown in Table 1 below.

[0123] Table 1 Performance test results of various embodiments and comparative examples

[0124]

[0125] Comparing and analyzing the test results in Table 1, we can see that:

[0126] For the silicon carbide honeycomb ceramics in each embodiment, the extreme difference of the splicing mud thickness is smaller than that of the comparative examples, and the thermal shock resistance temperature is higher than that of the comparative examples. This is because the diameter consistency of the thickness control material in each embodiment is good, it has a certain rigidity, and it still maintains good rigidity after contacting with the wet splicing mud. Silicon carbide honeycomb ceramic recycled powder is used as the main raw material, and its thermal conductivity and thermal expansion coefficient are closer to those of silicon carbide honeycomb ceramic unit blocks and splicing mud, and its thermal shock performance is better.

[0127] It can be seen from Examples 1-10 and 14-15 that with the increase of the content of fine-grained powder, hydroxypropyl methylcellulose and inorganic sol in the silicon carbide honeycomb ceramic recycled powder, the compressive strength of the thickness-controlled material shows a gradually increasing trend. When the strength meets the use requirements, the less the amount used, the lower the cost.

[0128] It can be seen from Examples 8, 10 and 11 that as the amount of redispersible latex powder increases, the attenuation of its compressive strength after soaking in water becomes smaller and smaller, which can ensure that it can still maintain good rigidity after being immersed in wet splicing mud during the splicing process.

[0129] It can be seen from Examples 8, 16 and 17 that with the increase in the amount of lubricant used, the compressive strength of the thickness-controlled material shows a gradually decreasing trend. When satisfying the extrusion performance, the amount of lubricant used should be minimized.

[0130] It can be seen from Examples 21-23 that the smaller the diameter of the thickness control material, the smaller the thickness of the splicing mud used, but the thermal shock performance is weakened; the larger the diameter of the thickness control material, the thicker the thickness of the splicing mud, but the back pressure increases.

[0131] From Examples 8, 12, 13, 16, 18, 19, and 20, it can be seen that the types of inorganic sol and lubricant have a certain influence on the strength, but both can meet the use requirements and have a good thickness control effect, and can be reasonably selected based on cost, etc.

[0132] Comparative Example 1 does not use thickness control materials, and its splicing mud thickness range is large, and its thermal shock resistance is poor. Comparative Example 2 uses silica sol-impregnated ceramic fiber sheets as thickness control materials, but its rigidity is poor during the extrusion process, resulting in dimensional compression, the thickness of the splicing mud is smaller than the thickness of the ceramic fiber sheet, and the control effect is poor. In addition, the ceramic fiber sheet is a flexible material that is easily subject to varying degrees of dimensional changes after being impregnated with silica sol, and its thickness consistency is poor, resulting in a larger thickness range than the comparison sample, and poor thermal shock resistance. In addition, the ceramic fiber sheet is considered a foreign material relative to silicon carbide honeycomb ceramics, and its thermal conductivity and thermal expansion coefficient are quite different, further deteriorating its thermal shock resistance. Comparative Sample 3 does not use redispersible latex powder, which is likely to cause a decrease in strength after contact with wet splicing mud, and the rigidity of the pressurization process is poorly maintained. The thickness of the splicing mud is smaller than the thickness of the thickness control material, and the thickness control effect is poor, and the thermal shock resistance effect is poor.

[0133] The above analysis results show that the thickness control material of the present invention has good properties and can be used to manufacture silicon carbide honeycomb ceramic bodies and can be preferably used as particle filters in various fields such as gasoline vehicles, diesel vehicles, steel, chemistry, and electricity.

[0134] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A thickness-controlled material, characterized in that: The thickness control material comprises silicon carbide powder, hydroxypropyl methylcellulose, redispersible latex powder, inorganic sol, water and lubricant; the silicon carbide powder comprises coarse-grained powder and fine-grained powder, and the particle size D of the coarse-grained powder is 50 The particle size D of the fine-grained powder is 20-30 μm. 50 1-2μm; The mass percentage of the coarse-grained powder is 90wt%-95wt%, and the balance is the fine-grained powder; In the thickness control material, the mass ratio of the silicon carbide powder, the hydroxypropyl methylcellulose, the redispersible latex powder, the inorganic sol, water, and the lubricant is 100: 1-2: 0.5-1.5: 10-20: 5-10: 2-5; The thickness-controlled material is cylindrical, and its cross-sectional diameter is 1.3-2 mm.

2. A thickness control material according to claim 1, characterized in that: The silicon carbide powder is a cooked powder, the chemical composition of which is consistent with that of a silicon carbide honeycomb ceramic unit block, and the mass percentage of silicon carbide in the cooked powder is greater than or equal to 60%.

3. The thickness-controlled material according to claim 1, characterized in that: The inorganic sol is one or more of silica sol, aluminum sol and zirconium sol.

4. The thickness-controlled material according to claim 1, characterized in that: The lubricant is one or more of soybean oil, tung oil, white oil, and industrial butter.

5. A method for preparing a thickness-controlled material according to any one of claims 1 to 4, characterized in that: The silicon carbide powder and the hydroxypropyl methylcellulose are mixed to obtain a solid mixture; the redispersible latex powder, the inorganic sol and water are mixed to obtain a liquid mixture; the liquid mixture is added to the solid mixture, kneaded and the lubricant is added, kneaded again, and then mud kneading, aging, extrusion molding, drying and cutting are carried out in sequence to obtain the thickness-controlled material.

6. An application of the thickness control material according to any one of claims 1 to 4, characterized in that: Used to prepare silicon carbide honeycomb ceramics.

7. A silicon carbide honeycomb ceramic, characterized in that: The silicon carbide honeycomb ceramic comprises a plurality of silicon carbide honeycomb ceramic unit blocks, two side walls of adjacent silicon carbide honeycomb ceramic unit blocks are connected and fixed by splicing mud, and a thickness control material as claimed in any one of claims 1 to 4 is provided between the two side walls.

Images