Method for preparing infrared radiation ceramic with high thermal shock resistance by slip casting method
By combining the sintering process of grouting and molding method, high -heat shock -based infrared radiation ceramics are prepared, which solves the problem of insufficient anti -thermal seismic properties of existing ceramics in high temperature environments. Crafts and reduced costs.
Patent Information
- Application Number
- CN202411555835.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-04
- Publication Date
- 2025-01-28
AI Technical Summary
The existing infrared radiation ceramics have low thermal shock resistance in high temperature environments, are prone to cracking and peeling due to thermal stress, and traditional preparation processes are costly and difficult to make complex shapes.
Adopt grouting forming legal system for high anti -thermal shock -based infrared radiation ceramics. By golf, screening and mixing raw materials such as green stone, alumina, red pillar stones, and kaolin to form a ceramic slurry, and then the grout is formed by grouting. After pre -fever and secondary sintering, it has obtained ceramics with high anti -heat seismic properties.
The high anti -heat seismic performance of infrared radiation ceramics can be achieved. The reflective strength can reach 486MPa. After 30 thermal shocks, the residual strength can only lose 8.43 %. At the same time, the craftsmanship is simplified, the cost is reduced, and the complex shape can be prepared.
Smart Images
Figure CN119371195A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of ceramic material preparation, in particular to a method for preparing high thermal shock resistance infrared radiation ceramics by using a slip injection molding method. Background Art
[0002] Infrared radiation ceramics are functional materials that can effectively absorb and convert heat energy into infrared radiation. Due to its excellent thermal properties and corrosion resistance, infrared radiation ceramics are widely used in metallurgy, machinery, electronics, and home appliances. Especially in high temperature environments, they can stably radiate infrared rays, improve energy efficiency, and reduce energy loss, making them an important component of industrial heating equipment and household heaters.
[0003] Existing infrared radiation ceramics perform well in many applications, but their thermal shock resistance in high temperature environments still needs to be improved. Traditional infrared radiation ceramics are prone to thermal stress during rapid heating and cooling, which can lead to cracking and peeling of the ceramics, affecting their service life and stability. The preparation of infrared radiation ceramics mainly includes processes such as extrusion molding, hot pressing molding and dry pressing molding. These methods are costly and difficult to produce ceramic products with more complex shapes, and the thermal shock resistance of the produced ceramic products is low. Summary of the invention
[0004] In order to solve the problem in the prior art that infrared radiation ceramics are prone to thermal stress during rapid heating and cooling, which leads to cracking and peeling of the ceramics, and the ceramic products produced have low thermal shock resistance, the present invention proposes a method for preparing infrared radiation ceramics with high thermal shock resistance by slip casting, which can solve the above problem and produce ceramic products with high thermal shock resistance.
[0005] The present invention proposes a method for preparing high thermal shock resistance infrared radiation ceramics by slip casting, which comprises the following steps in sequence:
[0006] Step 1, cordierite, alumina, andalusite and kaolin are respectively deironed, crushed, and sieved through a 4-8 mesh sieve to obtain cordierite powder, alumina powder, andalusite powder, and kaolin powder;
[0007] Step 2: first, according to the mass ratio, 50-80 parts of cordierite powder, 20-30 parts of alumina powder, 1-20 parts of andalusite powder, 1-20 parts of kaolin powder, 1-10 parts of sintering aid, 1-10 parts of rare earth modified additive and 1-10 parts of dispersant are mixed and added into a ball mill, then 100-200 parts of solvent are added, and finally, ball milling medium is added to perform ball milling process to obtain ceramic slurry;
[0008] Step 3, sieving the ceramic slurry obtained by ball milling, the mesh size is 100-200 mesh;
[0009] Step 4, sucking the ceramic slurry screened in step 3 into a grouting tank under negative pressure, and the stirring system in the grouting tank stirs the ceramic slurry to remove bubbles in a vacuum;
[0010] Step 5: The ceramic slurry after vacuum degassing is injected into the plaster mold by a grouting tank to obtain a green body, and the green body is taken out and naturally placed until the body shape is stable and then the body is repaired;
[0011] Step 6: Place the green body after the repair to dry naturally until the moisture content of the body is 1-2%; pre-sinter the green body at a temperature of 600-800°C for 0.5-2h; then cool to room temperature and perform secondary sintering at a temperature of 1000-1300°C for 1-3h to obtain infrared radiation ceramics with high thermal shock resistance.
[0012] Furthermore, in the step 2, the total mass ratio of the cordierite powder, alumina powder, andalusite powder, kaolin powder, sintering aid and dispersant to the solvent is 1:1 to 2.5.
[0013] Furthermore, in the step 2, the ball milling medium is alumina balls, the ball-to-material ratio during the mixing process is 2-5:1, the rotation speed is 100-300 r / min, and the mixing time is 5-20 h.
[0014] Furthermore, in step 4, the negative pressure is -0.5 to -0.1 MPa, the vacuum degree of vacuum defoaming is -0.06 to -0.1 MPa, the stirring speed is 50 to 200 r / min, and the stirring time is 10 to 30 min.
[0015] Furthermore, in step five, the grouting pressure is 0.2-0.5 MPa, and the pressure holding time is 10-30 min.
[0016] Furthermore, the sintering aid is one or more of yttrium oxide and magnesium oxide.
[0017] Furthermore, the rare earth modification additive is one or more of lanthanum oxide and cerium oxide.
[0018] Furthermore, the dispersant is one or more of ammonium polymethacrylate, sodium polymethacrylate, citric acid and sodium tripolyphosphate.
[0019] Furthermore, the solvent is deionized water or anhydrous ethanol.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] 1. The present invention adopts slip casting method combined with traditional solid phase sintering to prepare infrared radiation ceramics with high thermal shock resistance, using cordierite powder, alumina powder, andalusite powder, and kaolin powder as raw materials, adding sintering aids, rare earth modification additives and dispersants for mixing. Different from traditional dry pressing, the slip casting method adopted in the present invention has a simple molding process and can prepare ceramics with special-shaped structures. Infrared radiation ceramics with high thermal shock resistance are obtained by pre-sintering and re-sintering.
[0022] 2. The prepared samples have superior infrared radiation performance, good acid and alkali resistance, stronger thermal shock resistance, and excellent mechanical properties. The flexural strength can reach 486Mpa, and the residual strength after 30 thermal shocks only loses 8.43%.
[0023] 3. The slip injection molding method can accurately control the shape and size of ceramics, reduce material waste, improve material utilization, and meet the requirements of environmental protection and sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is the XRD diagram of the infrared radiation ceramic prepared in the present invention.
[0025] Figure 2 This is a SEM image of the infrared radiation ceramic prepared in Example 3 of the present invention. DETAILED DESCRIPTION
[0026] Advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments thereof, which are given by way of example only with reference to the accompanying drawings.
[0027] Example 1
[0028] This embodiment provides a method for preparing high thermal shock resistance infrared radiation ceramics by slip casting, and the specific steps are as follows:
[0029] Step 1: Select the raw materials of cordierite, alumina garnet and kaolin to remove impurities. For example, a lot of iron will be brought into the raw material processing process, so the materials must be deironed before loading. Grind some hard raw materials and pass through an 8-mesh sieve.
[0030] Step 2: First, mix 50 parts of cordierite powder, 20 parts of alumina powder, 1 part of andalusite powder, 1 part of kaolin powder, 1 part of yttrium oxide sintering aid, 1 part of lanthanum oxide rare earth modification additive and 1 part of polymethacrylate ammonium dispersant according to the mass ratio, add them into the ball mill, disperse them in 100 parts of deionized water, add ball milling media and ball mill to obtain ceramic slurry. The ball-to-material ratio of the mixing process is 5:1, the rotation speed is 100r / min, and the ball milling time is 20h.
[0031] Step 3: Sieve the ceramic slurry obtained by ball milling with a mesh size of 100 mesh.
[0032] Step 4: The sieved ceramic slurry is sucked into the grouting tank at a negative pressure of -0.1Mpa. The automatic stirring system in the grouting tank stirs the ceramic slurry for vacuum defoaming. The vacuum degree of vacuum defoaming is -0.06Mpa, the stirring speed is 50r / min, and the stirring time is 30min.
[0033] Step 5: Ceramic slurry is injected into the grouting pipe through compressed air to grout the gypsum mold. The grouting pressure is 0.2Mpa and the pressure is maintained for 10 minutes. After the pressure is maintained, the green body is taken out and placed naturally until it has a certain hardness and can maintain a stable shape. Then, a knife, towel, etc. are used to trim the green body.
[0034] Step 6: Place the green body to dry naturally until the moisture content of the body is 2%, and then pre-sinter the sample. The pre-sintering temperature is 600℃, and the temperature is kept for 2 hours. After cooling to room temperature, the secondary sintering is performed at a sintering temperature of 1000℃ and a sintering time of 3 hours to obtain a highly thermal shock resistant infrared radiation ceramic.
[0035] The density of the high thermal shock resistance infrared radiation ceramic obtained in this embodiment measured by Archimedes drainage method is 1.86 g / cm 3 , the porosity is 14%, the flexural strength obtained by instrument detection is 487.43Mpa, and the residual strength loss after 30 thermal shocks is 8.63%.
[0036] like Figure 1 , which is the XRD diagram of the high thermal shock resistance infrared radiation ceramic prepared by the present invention.
[0037] Example 2
[0038] This embodiment provides a method for preparing high thermal shock resistance infrared radiation ceramics by slip casting, and the specific steps are as follows:
[0039] Step 1: Select and remove impurities from raw materials such as cordierite, alumina, andalusite and kaolin. For example, a lot of iron will be introduced during the processing of raw materials, so the materials must be deironed before loading. Grind some hard raw materials and pass through a 4-mesh sieve.
[0040] Step 2: First, mix 80 parts of cordierite powder, 30 parts of alumina powder, 20 parts of andalusite powder, 20 parts of kaolin powder, 10 parts of magnesium oxide sintering aid, 10 parts of cerium oxide rare earth modification additive and 10 parts of sodium polymethacrylate dispersant according to the mass ratio, add them into the ball mill, disperse them in 200 parts of anhydrous ethanol, add ball milling media and ball mill to obtain ceramic slurry. The ball-to-material ratio of the mixing process is 2:1, the rotation speed is 300r / min, and the ball milling time is 5h.
[0041] Step 3: Sieve the ceramic slurry obtained by ball milling with a mesh size of 200 meshes.
[0042] Step 4: The sieved ceramic slurry is sucked into the grouting tank at a negative pressure of -0.5Mpa. The automatic stirring system in the grouting tank stirs the slurry for vacuum defoaming. The vacuum degree of vacuum defoaming is -0.1Mpa, the stirring speed is 200r / min, and the stirring time is 10min.
[0043] Step 5: Ceramic slurry is injected into the grouting pipe through compressed air to grout the gypsum mold. The grouting pressure is 0.5Mpa and the pressure is maintained for 30 minutes. After the pressure is maintained, the green blank is taken out and naturally placed until it has a certain hardness and can maintain a stable shape. Use a knife, towel, etc. to trim the green blank.
[0044] Step 6: Place the green body to dry naturally until the moisture content of the body is 1%, and then pre-sinter the sample. The pre-sintering temperature is 800℃ and kept for 0.5h. After cooling to room temperature, the secondary sintering is performed at 1300℃ and the sintering time is 1h to obtain high thermal shock resistance infrared radiation ceramics.
[0045] The density of the high thermal shock resistance infrared radiation ceramic obtained in this embodiment measured by the Archimedean drainage method is 1.89 g / cm 3 , the porosity is 13.6%, the flexural strength obtained by instrument detection is 486.34Mpa, and the residual strength loss after 30 thermal shocks is 8.84%.
[0046] Example 3
[0047] This embodiment provides a method for preparing high thermal shock resistance infrared radiation ceramics by slip casting, and the specific steps are as follows:
[0048] Step 1: Select and remove impurities from raw materials such as cordierite, alumina, andalusite and kaolin. For example, a lot of iron will be introduced during the processing of raw materials, so the materials must be deironed before loading. Grind some hard raw materials and pass through a 6-mesh sieve.
[0049] Step 2: First, add 70 parts of cordierite powder, 25 parts of alumina powder, 10 parts of andalusite powder, 5 parts of kaolin powder, 5 parts of (yttrium oxide + magnesium oxide) sintering aid, 5 parts of lanthanum oxide rare earth modified additive and 5 parts of (sodium polymethacrylate + sodium tripolyphosphate) dispersant to a ball mill according to the mass ratio, disperse them in 125 parts of deionized water, add ball milling media and ball mill to obtain ceramic slurry. The ball-to-material ratio of the mixing process is 2:1, the rotation speed is 250r / min, and the ball milling time is 8h.
[0050] The mass ratio of yttrium oxide to magnesium oxide in the sintering aid of this embodiment is 1:2. The mass ratio of sodium polymethacrylate to sodium tripolyphosphate in the dispersant is 1:1.
[0051] Step 3: Sieve the ceramic slurry obtained by ball milling with a mesh size of 150 mesh.
[0052] Step 4: The sieved ceramic slurry is sucked into the grouting tank at a negative pressure of -0.3Mpa. The automatic stirring system in the grouting tank stirs the slurry for vacuum defoaming. The vacuum degree of vacuum defoaming is -0.08Mpa, the stirring speed is 150r / min, and the stirring time is 25min.
[0053] Step 5: Ceramic slurry is injected into the grouting pipe through compressed air to grout the gypsum mold. The grouting pressure is 0.3Mpa and the pressure is maintained for 25 minutes. After the pressure is maintained, the green blank is taken out and placed naturally until it has a certain hardness and can maintain a stable shape. Then, a knife, towel, etc. are used to trim the green blank.
[0054] Step 6: Place the green body to dry naturally until the moisture content of the body is 1.5%, and then pre-sinter the sample. The pre-sintering temperature is 750℃ and kept for 1 hour. After cooling to room temperature, the secondary sintering is performed at 1100℃ and the sintering time is 1.5 hours to obtain high thermal shock resistance infrared radiation ceramics.
[0055] The density of the high thermal shock resistance infrared radiation ceramic obtained in this embodiment measured by Archimedes drainage method is 1.82 g / cm 3 , the porosity is 14.3%, the flexural strength detected by the instrument is 488.42Mpa, and the residual strength loss after 30 thermal shocks is 8.67%.
[0056] like Figure 2 , which is a SEM image of the high thermal shock resistance infrared radiation ceramic prepared in this embodiment.
[0057] Example 4
[0058] This embodiment provides a method for preparing high thermal shock resistance infrared radiation ceramics by slip casting, and the specific steps are as follows:
[0059] Step 1: Select and remove impurities from raw materials such as cordierite, alumina, andalusite and kaolin. For example, a lot of iron will be introduced during the processing of raw materials, so the materials must be deironed before loading. Grind some hard raw materials and pass through an 8-mesh sieve.
[0060] Step 2: First, mix 50 parts of cordierite powder, 20 parts of alumina powder, 3 parts of andalusite powder, 2 parts of kaolin powder, 2 parts of (yttrium oxide + magnesium oxide) sintering aid, 1 part of (lanthanum oxide + cerium oxide) rare earth modification additive and 2 parts of (sodium polymethacrylate + ammonium polymethacrylate + citric acid + sodium tripolyphosphate) dispersant in a ball mill according to the mass ratio, disperse them in 200 parts of deionized water, add ball milling media and ball mill to obtain ceramic slurry. The ball-to-material ratio of the mixing process is 2.5:1, the rotation speed is 200r / min, and the ball milling time is 15h.
[0061] The mass ratio of sodium polymethacrylate, ammonium polymethacrylate, citric acid and sodium tripolyphosphate in the dispersant of this embodiment is 1:1:1:1. The mass ratio of yttrium oxide and magnesium oxide in the sintering aid is 1:1. The mass ratio of lanthanum oxide and cerium oxide in the rare earth modification additive is 1:1.
[0062] Step 3: Sieve the ceramic slurry obtained by ball milling with a mesh size of 150 mesh.
[0063] Step 4: The sieved ceramic slurry is sucked into the grouting tank at a negative pressure of -0.1Mpa. The automatic stirring system in the grouting tank stirs the slurry for vacuum defoaming. The vacuum degree of vacuum defoaming is -0.06Mpa, the stirring speed is 120r / min, and the stirring time is 20min.
[0064] Step 5: Ceramic slurry is injected into the grouting pipe through compressed air to grout the gypsum mold. The grouting pressure is 0.4Mpa and the pressure is maintained for 20 minutes. After the pressure is maintained, the green blank is taken out and placed naturally until it has a certain hardness and can maintain a stable shape. Then, a knife, towel, etc. are used to trim the green blank.
[0065] Step 6: Place the green body to dry naturally until the moisture content of the body is 1.5%, and then pre-sinter the sample. The pre-sintering temperature is 800℃ for 2h, and then it is lowered to room temperature and then sintered again. The sintering temperature is 1150℃ and the sintering time is 1.5h to obtain high thermal shock resistance infrared radiation ceramics.
[0066] The density of the high thermal shock resistance infrared radiation ceramic obtained in this embodiment measured by the Archimedean drainage method is 1.93 g / cm 3 , the porosity is 12.8%, the flexural strength obtained by instrument detection is 488.76Mpa, and the residual strength loss after 30 thermal shocks is 8.48%.
[0067] The preparation method of the present invention is a traditional solid-phase sintering method, and the process is formulated based on the following considerations: the porosity and structural strength of the sample can be changed by changing the ratio of different raw materials; the microstructure of the material can be regulated by adopting different sintering temperatures and holding times, thereby optimizing its mechanical properties and pore characteristics; the use of a grouting molding process during molding not only improves the uniformity of the material, but also enhances its mechanical strength.
[0068] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.
Claims
1. A method for preparing high thermal shock resistance infrared radiation ceramics by slip casting, characterized in that: The following steps are included in sequence: Step 1, cordierite, alumina, andalusite and kaolin are respectively deironed, crushed, and sieved through a 4-8 mesh sieve to obtain cordierite powder, alumina powder, andalusite powder, and kaolin powder; Step 2: first, according to the mass ratio, 50-80 parts of cordierite powder, 20-30 parts of alumina powder, 1-20 parts of andalusite powder, 1-20 parts of kaolin powder, 1-10 parts of sintering aid, 1-10 parts of rare earth modified additive and 1-10 parts of dispersant are mixed and added into a ball mill, then 100-200 parts of solvent are added, and finally, ball milling medium is added to perform ball milling process to obtain ceramic slurry; Step 3, sieving the ceramic slurry obtained by ball milling, the mesh size is 100-200 mesh; Step 4, sucking the ceramic slurry screened in step 3 into a grouting tank under negative pressure, and the stirring system in the grouting tank stirs the ceramic slurry to remove bubbles in a vacuum; Step 5: The ceramic slurry after vacuum degassing is injected into the plaster mold by a grouting tank to obtain a green body, and the green body is taken out and naturally placed until the body shape is stable and then the body is repaired; Step 6: Place the green body after the repair to dry naturally until the moisture content of the body is 1-2%; pre-sinter the green body at a temperature of 600-800°C for 0.5-2h; then cool to room temperature and perform secondary sintering at a temperature of 1000-1300°C for 1-3h to obtain infrared radiation ceramics with high thermal shock resistance.
2. The method for preparing high thermal shock resistance infrared radiation ceramics by slip casting according to claim 1, characterized in that: In the step 2, the total mass ratio of cordierite powder, alumina powder, andalusite powder, kaolin powder, sintering aid and dispersant to the solvent is 1:1-2.
5.
3. The method for preparing high thermal shock resistance infrared radiation ceramics by slip casting according to claim 2, characterized in that: In the step 2, the ball milling medium is alumina balls, the ball-to-material ratio in the mixing process is 2-5:1, the rotation speed is 100-300 r / min, and the mixing time is 5-20 hours.
4. The method for preparing high thermal shock resistance infrared radiation ceramics by slip casting according to claim 2, characterized in that: In the step 4, the negative pressure is -0.5 to -0.1 MPa, the vacuum degree of vacuum defoaming is -0.06 to -0.1 MPa, the stirring speed is 50 to 200 r / min, and the stirring time is 10 to 30 min.
5. The method for preparing high thermal shock resistance infrared radiation ceramics by slip casting according to claim 2, characterized in that: In the step 5, the grouting pressure is 0.2-0.5 MPa, and the pressure holding time is 10-30 min.
6. A method for preparing high thermal shock resistance infrared radiation ceramics by slip casting according to any one of claims 1 to 5, characterized in that: The sintering aid is one or more of yttrium oxide and magnesium oxide.
7. A method for preparing high thermal shock resistance infrared radiation ceramics by slip casting according to any one of claims 1 to 5, characterized in that: The rare earth modification additive is one or more of lanthanum oxide and cerium oxide.
8. A method for preparing high thermal shock resistance infrared radiation ceramics by slip casting according to any one of claims 1 to 5, characterized in that: The dispersant is one or more of ammonium polymethacrylate, sodium polymethacrylate, citric acid and sodium tripolyphosphate.
9. The method for preparing high thermal shock resistance infrared radiation ceramics by slip casting according to claim 8, characterized in that: The solvent is deionized water or anhydrous ethanol.