Anti-cracking ceramic heating plate and preparation method thereof

Abstract

The invention provides an anti-cracking ceramic heating plate and a preparation method thereof.The preparation method comprises the steps that raw materials with different proportions are adopted, under the condition of different operation parameters, cold isostatic pressing forming, hot pressing sintering and machining are sequentially conducted, and a ceramic plate body and a ceramic sleeve are prepared respectively; and after the ceramic plate body and the ceramic sleeve are assembled, carrying out third hot pressing sintering to obtain the anti-cracking ceramic heating plate. According to the preparation method, the heat conductivity of the ceramic plate body and the heat conductivity of the ceramic sleeve are controlled to be within a specific range, cracks generated on the surface of the ceramic plate body due to temperature difference are avoided, and the obtained anti-cracking ceramic heating plate is suitable for large-scale application and popularization.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic heating plates, and in particular to an anti-cracking ceramic heating plate and a preparation method thereof. Background Art

[0002] Aluminum nitride ceramics have excellent heat dissipation, stability, and insulation properties. They are widely used in rapidly developing fields such as semiconductors, intelligent power components, automotive electronics, and solar energy. In the semiconductor manufacturing process, chemical vapor deposition is required to coat the wafers and prepare semiconductor films in an environment of raw materials such as methane and chlorine. At the same time, ceramic heaters are used to heat the wafers, so that chemical vapor deposition has a better effect and a more uniform film is obtained.

[0003] CN114150295A discloses a ceramic heating plate, a preparation method, a mold and a chemical vapor deposition device. The ceramic raw material powder is pre-pressed at room temperature, and the radio frequency electrode and the heating component and the ceramic raw material powder are pre-formed, and then the ceramic heating plate is formed by hot pressing with the fired ceramic tube. The high-temperature firing once avoids the repeated high-temperature process that easily causes the change of the internal resistance of the heating plate body, and the ceramic grains grow twice due to the secondary sintering, which changes the ceramic properties, and the mechanical and physical properties of the ceramic matrix deteriorate, thereby improving the thermal uniformity and service life of the ceramic heating plate.

[0004] CN110230043A discloses a chemical vapor deposition device, a ceramic heating plate and a method for preparing the ceramic heating plate. The ceramic heating plate includes a heating plate body and a ceramic tube. The heating plate body includes a first aluminum nitride ceramic substrate, a heating plate and a second aluminum nitride ceramic substrate stacked in sequence from bottom to top; the layers are bonded by thermally conductive ceramic slurry and formed into a whole after sintering; the thermal conductivity of the obtained first ceramic body is lower than the thermal conductivity of the second ceramic body. The chemical vapor deposition device includes the ceramic heating plate. The method for preparing the ceramic heating plate includes bonding the first aluminum nitride ceramic substrate, the heating plate, the second aluminum nitride ceramic substrate, the electrode plate and the third aluminum nitride ceramic substrate in sequence by ceramic slurry, and obtaining the heating plate body by hot pressing and sintering.

[0005] CN115677353A discloses an aluminum nitride-based conductive ceramic and a preparation method thereof. Aluminum nitride powder, metal powder, sintering aid powder, organic solvent, binder, and dispersant are mixed in a ball mill to obtain a mixed slurry; the mixed slurry is subjected to vacuum degassing treatment and molding to obtain a first green blank; the first green blank is placed in a binder removal furnace for binder removal treatment to obtain a ceramic green blank; the ceramic green blank after binder removal is placed in a high-temperature furnace and fired at high temperature in a nitrogen atmosphere to obtain a eutectic aluminum nitride-based conductive ceramic material; the eutectic aluminum nitride-based conductive ceramic material is crushed and molded to obtain a second green blank; the second green blank is placed in a hot pressing and shaking sintering furnace for hot pressing and sintering to obtain a dense eutectic aluminum nitride-based conductive ceramic material.

[0006] However, in the above patent, the heating plate and the sleeve are both made of the same aluminum nitride material. Due to the temperature difference within the heating surface, cracks may be generated in the center of the heating surface. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a crack-resistant ceramic heating plate and a preparation method thereof. The ceramic plate body and the ceramic sleeve are prepared respectively by using raw materials in different proportions, and the thermal conductivity of the plate body and the sleeve materials is controlled to avoid cracks on the plate surface due to temperature difference.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing a crack-resistant ceramic heating plate, the method comprising the following steps:

[0010] (1) The ceramic disc raw material is pretreated to obtain a pretreated ceramic disc powder; the pretreated ceramic disc powder is sequentially subjected to a first cold isostatic pressing, a first hot pressing sintering and mechanical processing to obtain a ceramic disc; the ceramic disc raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 2wt% to 5wt% of the total mass of the ceramic disc raw material;

[0011] During the first cold isostatic pressing process, a heating wire and a heating wire terminal are placed;

[0012] (2) The ceramic sleeve raw material is pretreated to obtain a pretreated ceramic sleeve powder; the pretreated ceramic sleeve powder is sequentially subjected to a second cold isostatic pressing, a second normal pressure sintering and mechanical processing to obtain a ceramic sleeve; the ceramic sleeve raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 1wt% to 3wt% of the total mass of the ceramic sleeve raw material;

[0013] (3) After the ceramic disc body of step (1) and the ceramic sleeve of step (2) are assembled, a third hot pressing sintering is performed to achieve the combination of the ceramic disc body and the ceramic sleeve to obtain the anti-cracking ceramic heating disc.

[0014] The preparation method of the anti-cracking ceramic heating plate of the present invention adopts raw materials of different proportions to prepare a ceramic plate body and a ceramic sleeve respectively, wherein the Y2O3 powder in the raw material of the ceramic plate body accounts for 2wt% to 5wt% of the total mass of the raw material of the ceramic plate body, under which condition the thermal conductivity of the ceramic plate body is 100 to 240W / m·K; the Y2O3 powder in the raw material of the ceramic sleeve accounts for 1wt% to 3wt% of the total mass of the raw material of the ceramic sleeve, under which condition the thermal conductivity of the ceramic sleeve is 40 to 160W / Mk, and the thermal conductivity of the ceramic plate body is 1.5 to 2.5 times that of the ceramic sleeve. When the proportion of Y2O3 powder in the raw material of the ceramic plate body is low, the thermal conductivity of the ceramic plate body is less than 1.5 times that of the ceramic sleeve, the thermal conductivities of the two are close, there is more heat diffusion from the ceramic plate body to the ceramic sleeve, the surface temperature uniformity of the ceramic plate body is poor, and the central part of the ceramic plate body may crack. When the proportion of Y2O3 powder in the raw material of the ceramic disc is high, the thermal conductivity of the ceramic disc is more than 2.5 times that of the ceramic sleeve. Since the thermal expansion coefficient is positively correlated with the thermal conductivity, the difference in thermal expansion coefficients between the ceramic disc and the ceramic sleeve is too large, and the ceramic disc is damaged.

[0015] The preparation method of the anti-cracking ceramic heating plate described in the present invention performs cold isostatic pressing on the pretreated ceramic plate body powder and the pretreated ceramic sleeve powder, and the function is: the first cold isostatic pressing of the plate body is to place the heating wire and the terminal in the plate body, and at the same time complete the preforming of the plate body, increase the overall density to about 50% to 60%, reduce the shrinkage during the sintering process, and prevent the position deformation caused by the heating wire being squeezed during sintering, and then perform hot pressing sintering treatment, the function of which is to densify the formed sample to approach the theoretical density of aluminum nitride 100%; finally, after the ceramic plate body and the ceramic sleeve are assembled, the third hot pressing sintering is performed to achieve a firm combination of the ceramic plate body and the ceramic sleeve, thereby obtaining an anti-cracking ceramic heating plate.

[0016] The Y2O3 powder of the present invention accounts for 2wt% to 5wt% of the total mass of the ceramic disc raw material, for example, it can be 2wt%, 2.2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt% or 5wt%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] The Y2O3 powder accounts for 1wt% to 3wt% of the total mass of the ceramic sleeve raw material, for example, it can be 1wt%, 1.1wt%, 1.3wt%, 1.5wt%, 2wt%, 2.5wt% or 3wt%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, the pressure of the first cold isostatic pressing in step (1) is 200-250 MPa, for example, it can be 200 MPa, 210 MPa, 215 MPa, 220 MPa, 230 MPa, 240 MPa or 250 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] The present invention preferably uses a pressure of 200 to 250 MPa for the first cold isostatic pressing, which has the advantage of obtaining a preformed disc with a higher density while ensuring a certain disc strength. When the pressure of the first cold isostatic pressing is low, the disc density will be poor, the strength will be low, cracking and corner collapse will occur during processing, and the shrinkage during sintering will be large, causing serious deformation of the heating wire; when the pressure of the first cold isostatic pressing is high, it will cause internal layer cracking, resulting in a decrease in mechanical properties and difficulty in sintering.

[0020] Preferably, the holding time of the first cold isostatic pressing is 20 to 30 minutes, for example, it can be 20 minutes, 21 minutes, 23 minutes, 25 minutes, 26 minutes, 27 minutes, 28 minutes or 30 minutes, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, the first cold isostatic pressing of the pretreated ceramic disc powder in step (1) is carried out in two steps. First, the first part of the pretreated ceramic disc powder is added and subjected to the first cold isostatic pressing to obtain a prefabricated body. Then, a heating wire and a heating wire terminal are placed on the surface of the prefabricated body, and the remaining part of the pretreated ceramic disc powder is added, and the first cold isostatic pressing is carried out again.

[0022] Preferably, the mass of the first part of pretreated ceramic disc powder is 60wt% to 70wt% of the total mass of the pretreated ceramic disc powder, for example, it can be 60wt%, 62wt%, 63wt%, 65wt%, 66wt%, 68wt% or 70wt%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the temperature of the first hot pressing sintering in step (1) is 1600-1800°C, for example, it can be 1600°C, 1610°C, 1630°C, 1650°C, 1700°C, 1750°C, 1780°C or 1800°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the first hot pressing sintering pressure is 10-30 MPa, for example, 10 MPa, 12 MPa, 15 MPa, 18 MPa, 20 MPa, 25 MPa or 30 MPa, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0025] Preferably, the first hot pressing sintering time is 2 to 5 hours, for example, it can be 2 hours, 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.5 hours, 4 hours or 5 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the pressure of the second cold isostatic pressing in step (2) is 150-250 MPa, for example, it can be 150 MPa, 160 MPa, 170 MPa, 200 MPa, 220 MPa, 230 MPa or 250 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the holding time of the second cold isostatic pressing is 30 to 50 min, for example, it can be 30 min, 32 min, 35 min, 38 min, 40 min, 45 min, 48 min or 50 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the temperature of the second normal pressure sintering in step (2) is 1600-1800°C, for example, it can be 1600°C, 1610°C, 1630°C, 1650°C, 1700°C, 1750°C, 1780°C or 1800°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the second pressureless sintering time is 1 to 4 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 3.8 hours or 4 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the pretreatment in step (1) and step (2) comprises sequentially performing wet ball milling, drying and screening.

[0031] Preferably, the mass ratio of the mixture to the grinding balls in the wet ball mill is (2-6):1, for example, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 5:1 or 6:1, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the medium of the wet ball milling comprises anhydrous alcohol with a purity of 99.7%.

[0033] Preferably, the mass ratio of the mixture and the medium in the wet ball milling is 1:(1-1.5), for example, it can be 1:1, 1:1.05, 1:1.1, 1:1.2, 1:1.25, 1:1.3 or 1:1.5, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the rotation speed of the wet ball mill is 150-300 r / min, for example, it can be 150 r / min, 155 r / min, 160 r / min, 180 r / min, 200 r / min, 250 r / min, 270 r / min or 300 r / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the wet ball milling time is 20 to 30 hours, for example, it can be 20 hours, 21 hours, 23 hours, 24 hours, 25 hours, 27 hours, 29 hours or 30 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the drying temperature is 60-80°C, for example, it can be 60°C, 62°C, 65°C, 68°C, 70°C, 73°C, 75°C or 80°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the drying time is 12 to 18 hours, for example, it can be 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 16.5 hours, 17 hours or 18 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, the screening is performed using a sieve of 80 to 120 mesh, for example, 80 mesh, 90 mesh, 100 mesh, 110 mesh, 115 mesh or 120 mesh, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the mechanical processing in step (1) and step (2) includes fine grinding.

[0040] Preferably, the temperature of the third hot pressing sintering in step (3) is 1750-1900°C, for example, it can be 1750°C, 1760°C, 1770°C, 1800°C, 1830°C, 1850°C, 1880°C or 1900°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] The present invention preferably sets the temperature of the third hot pressing sintering to 1750°C to 1900°C, which has the advantage of ensuring that the disc body grain size does not grow due to excessively high temperature, thereby reducing thermal conductivity, while completing a good connection between the sleeve and the disc body. When the temperature of the third hot pressing sintering is low, the disc body and the sleeve cannot be well connected, the weld sealing is poor, and the connection strength is low; when the temperature of the third hot pressing sintering is high, the disc body grain size grows abnormally, and the disc body thermal conductivity is reduced.

[0042] Preferably, the third hot pressing sintering pressure is 5-20 MPa, for example, 5 MPa, 7 MPa, 9 MPa, 10 MPa, 12 MPa, 15 MPa or 20 MPa, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0043] The present invention preferably uses a third hot pressing sintering pressure of 5 to 20 MPa, which has the advantage of not damaging the sleeve and causing deformation of the disc while ensuring good connection between the disc and the sleeve. When the third hot pressing sintering pressure is low, the disc and sleeve connection surfaces cannot fit tightly during the sintering process, resulting in poor welding quality, poor air tightness, and low connection strength; when the third hot pressing sintering pressure is high, cracks will form in the sleeve during the pressure process, causing damage and deformation of the disc during the sintering process.

[0044] The pressure of the third hot pressing sintering in the present invention is 5-20MPa, which is lower than the pressure of the first hot pressing sintering of 10-30MPa, because the two have different purposes and the states before sintering are also different; the first hot pressing sintering is to achieve complete densification of the disc body, and the disc body changes from 50-60% density of the preform to 99-100% density. Before sintering, there are many pores between the powders inside the disc body, and a higher pressure is required as a driving force to achieve sintering between the powders and eliminate the pores; the third hot pressing sintering is to achieve the connection between the disc body and the sleeve after sintering. Before sintering, both are close to the theoretical density. The pressure required for the bonding of the welding surfaces is used to ensure the close fit of the welding surfaces, so that the surface atoms in the disc body and the sleeve can diffuse with each other during the sintering process, and the surfaces form a good bond.

[0045] Preferably, the third hot pressing sintering time is 1 to 4 hours, for example, it can be 1 hour, 1.3 hours, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.7 hours or 4 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0047] (1) The ceramic disc raw material is pretreated to obtain a pretreated ceramic disc powder; the pretreated ceramic disc powder is sequentially subjected to a first cold isostatic pressing process at a pressure of 200 to 250 MPa and a holding time of 20 to 30 min, a first hot pressing sintering process at a temperature of 1600 to 1800° C. and a pressure of 10 to 30 MPa for 2 to 5 h, and fine grinding to obtain a ceramic disc; the ceramic disc raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 2wt% to 5wt% of the total mass of the ceramic disc raw material;

[0048] The first cold isostatic pressing of the pretreated ceramic disc body powder is performed in two steps, firstly, the first part of the pretreated ceramic disc body powder is added and subjected to the first cold isostatic pressing to obtain a prefabricated body, then a heating wire and a heating wire terminal are placed on the surface of the prefabricated body, and then the remaining part of the pretreated ceramic disc body powder is added, and the first cold isostatic pressing is performed again; the mass of the first part of the pretreated ceramic disc body powder is 60wt% to 70wt% of the total mass of the pretreated ceramic disc body powder;

[0049] (2) The ceramic sleeve raw material is pretreated to obtain a pretreated ceramic sleeve powder; the pretreated ceramic sleeve powder is sequentially subjected to a second cold isostatic pressing process at a pressure of 150 to 250 MPa and a holding time of 30 to 50 min, a second normal pressure sintering process at a temperature of 1600 to 1800° C. for 1 to 4 h, and fine grinding to obtain a ceramic sleeve; the ceramic sleeve raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 1wt% to 3wt% of the total mass of the ceramic sleeve raw material;

[0050] The pretreatment in step (1) and step (2) comprises sequentially performing wet ball milling at a rotation speed of 150 to 300 r / min for 20 to 30 hours and drying at a temperature of 60 to 80° C. for 12 to 18 hours, followed by screening using a sieve of 80 to 120 meshes;

[0051] The mass ratio of the mixed material to the grinding balls in the wet ball mill is (2-6):1; the medium of the wet ball mill includes anhydrous alcohol with a purity of 99.7%; the mass ratio of the mixed material to the medium of the wet ball mill is 1:(1-1.5);

[0052] (3) After the ceramic plate body of step (1) and the ceramic sleeve of step (2) are assembled, a third hot pressing sintering is performed at a temperature of 1750-1900° C. and a pressure of 5-20 MPa for 1-4 hours to achieve the bonding of the ceramic plate body and the ceramic sleeve to obtain the anti-cracking ceramic heating plate.

[0053] In a second aspect, the present invention further provides an anti-cracking ceramic heating plate, wherein the anti-cracking ceramic heating plate is prepared by the method for preparing the anti-cracking ceramic heating plate described in the first aspect;

[0054] The anti-cracking ceramic heating plate comprises a ceramic plate body and a ceramic sleeve which are combined with each other;

[0055] A heating wire is arranged in the ceramic disc body; the heating wire is connected to the heating wire terminal;

[0056] A heating rod is arranged in the ceramic sleeve; the heating rod is connected to the heating wire terminal.

[0057] The thermal conductivity of the ceramic plate body in the anti-cracking ceramic heating plate of the present invention is 1.5 to 2.5 times that of the ceramic sleeve, and the problem of cracks on the surface of the ceramic plate body due to temperature difference will not occur, so that the service life of the ceramic heating plate is greatly improved.

[0058] Compared with the prior art, the present invention has at least the following beneficial effects:

[0059] The present invention provides a method for preparing an anti-cracking ceramic heating plate, which adopts raw materials of different proportions and performs cold isostatic pressing, hot pressing sintering and mechanical processing in sequence under different operating parameters to respectively prepare a ceramic plate body and a ceramic sleeve, and controls the thermal conductivity of the ceramic plate body and the ceramic sleeve within a specific range to avoid cracks on the plate body surface due to temperature difference. The obtained anti-cracking ceramic heating plate is suitable for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 It is a cross-sectional view of an anti-cracking ceramic heating plate obtained by the method for preparing an anti-cracking ceramic heating plate provided in Example 1 of the present invention.

[0061] In the figure: 1-ceramic disc; 2-ceramic sleeve; 3-heating wire; 4-heating rod; 5-heating wire terminal. DETAILED DESCRIPTION

[0062] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0063] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0064] Example 1

[0065] This embodiment provides a method for preparing an anti-cracking ceramic heating plate, the preparation method comprising the following steps:

[0066] (1) The ceramic disc raw material is pretreated to obtain a pretreated ceramic disc powder; the pretreated ceramic disc powder is sequentially subjected to a first cold isostatic pressing process at a pressure of 220 MPa and a holding time of 24 min, a first hot pressing process at a temperature of 1730° C. and a pressure of 18 MPa for 2.5 h, and fine grinding to obtain a ceramic disc; the ceramic disc raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 2.5 wt% of the total mass of the ceramic disc raw material;

[0067] The first cold isostatic pressing of the pretreated ceramic disc body powder is performed in two steps, firstly, the first part of the pretreated ceramic disc body powder is added and subjected to the first cold isostatic pressing to obtain a prefabricated body, then a heating wire and a heating wire terminal are placed on the surface of the prefabricated body, and then the remaining part of the pretreated ceramic disc body powder is added, and the first cold isostatic pressing is performed again; the mass of the first part of the pretreated ceramic disc body powder is 66wt% of the total mass of the pretreated ceramic disc body powder;

[0068] (2) The ceramic sleeve raw material is pretreated to obtain a pretreated ceramic sleeve powder; the pretreated ceramic sleeve powder is sequentially subjected to a second cold isostatic pressing process at a pressure of 200 MPa and a holding time of 40 min, a second normal pressure sintering process at a temperature of 1680° C. for 2 h, and fine grinding to obtain a ceramic sleeve; the ceramic sleeve raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 2wt% of the total mass of the ceramic sleeve raw material;

[0069] The pretreatment in step (1) and step (2) includes wet ball milling at a rotation speed of 200 r / min for 26 hours and drying at a temperature of 72° C. for 15 hours, followed by screening using a 100-mesh sieve;

[0070] The mass ratio of the mixed material to the grinding balls in the wet ball mill is 5:1; the medium of the wet ball mill includes anhydrous alcohol with a purity of 99.7%; the mass ratio of the mixed material to the medium of the wet ball mill is 1:1.2;

[0071] (3) The ceramic plate body of step (1) and the ceramic sleeve of step (2) are subjected to a third hot pressing sintering at a temperature of 1800° C. and a pressure of 12 MPa for 1.4 hours to achieve the bonding of the ceramic plate body and the ceramic sleeve to obtain the anti-cracking ceramic heating plate.

[0072] The cross-sectional view of the anti-cracking ceramic heating plate prepared in this embodiment is as follows: Figure 1 shown.

[0073] The anti-cracking ceramic heating plate includes a ceramic plate body 1 and a ceramic sleeve 2 which are combined with each other; a heating wire 3 is arranged in the ceramic plate body 1; the heating wire 3 is connected to the heating wire terminal 5; a heating rod 4 is arranged in the ceramic sleeve 2; the heating rod 4 is connected to the heating wire terminal 5.

[0074] The thermal conductivity of the ceramic sleeve in the crack-proof ceramic heating plate prepared in this embodiment is 103 W / m·K, and the thermal conductivity of the ceramic plate body is 183 W / m·K, which is 1.78 times the thermal conductivity of the ceramic sleeve.

[0075] Example 2

[0076] This embodiment provides a method for preparing an anti-cracking ceramic heating plate, the preparation method comprising the following steps:

[0077] (1) The ceramic disc raw material is pretreated to obtain a pretreated ceramic disc powder; the pretreated ceramic disc powder is sequentially subjected to a first cold isostatic pressing process at a pressure of 200 MPa and a holding time of 30 min, a first hot pressing sintering process at a temperature of 1600° C. and a pressure of 30 MPa for 5 h, and fine grinding to obtain a ceramic disc; the ceramic disc raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 5wt% of the total mass of the ceramic disc raw material;

[0078] The first cold isostatic pressing of the pretreated ceramic disc body powder is performed in two steps, firstly, the first part of the pretreated ceramic disc body powder is added and subjected to the first cold isostatic pressing to obtain a prefabricated body, then a heating wire and a heating wire terminal are placed on the surface of the prefabricated body, and then the remaining part of the pretreated ceramic disc body powder is added, and the first cold isostatic pressing is performed again; the mass of the first part of the pretreated ceramic disc body powder is 70wt% of the total mass of the pretreated ceramic disc body powder;

[0079] (2) The ceramic sleeve raw material is pretreated to obtain a pretreated ceramic sleeve powder; the pretreated ceramic sleeve powder is sequentially subjected to a second cold isostatic pressing process at a pressure of 250 MPa and a holding time of 30 min, a second normal pressure sintering process at a temperature of 1800° C. for 4 h, and fine grinding to obtain a ceramic sleeve; the ceramic sleeve raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 1wt% of the total mass of the ceramic sleeve raw material;

[0080] The pretreatment in step (1) and step (2) includes wet ball milling at a rotation speed of 300 r / min for 30 hours and drying at a temperature of 80° C. for 18 hours, followed by screening using a 120-mesh sieve;

[0081] The mass ratio of the mixed material to the grinding balls in the wet ball mill is 2:1; the medium of the wet ball mill includes anhydrous alcohol with a purity of 99.7%; the mass ratio of the mixed material to the medium of the wet ball mill is 1:1.5;

[0082] (3) After the ceramic plate body of step (1) and the ceramic sleeve of step (2) are assembled, a third hot pressing sintering is performed at a temperature of 1900° C. and a pressure of 20 MPa for 4 hours to achieve the bonding of the ceramic plate body and the ceramic sleeve to obtain the anti-cracking ceramic heating plate.

[0083] The thermal conductivity of the ceramic sleeve in the crack-proof ceramic heating plate prepared in this embodiment is 91 W / m·K, and the thermal conductivity of the ceramic plate body is 225 W / m·K, which is 2.47 times the thermal conductivity of the ceramic sleeve.

[0084] Example 3

[0085] This embodiment provides a method for preparing an anti-cracking ceramic heating plate, the preparation method comprising the following steps:

[0086] (1) The ceramic disc raw material is pretreated to obtain a pretreated ceramic disc powder; the pretreated ceramic disc powder is sequentially subjected to a first cold isostatic pressing process at a pressure of 240 MPa and a holding time of 21 min, a first hot pressing process at a temperature of 1730° C. and a pressure of 26 MPa for 4.3 h, and fine grinding to obtain a ceramic disc; the ceramic disc raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 4.5wt% of the total mass of the ceramic disc raw material;

[0087] The first cold isostatic pressing of the pretreated ceramic disc body powder is performed twice, firstly, the first part of the pretreated ceramic disc body powder is added and subjected to the first cold isostatic pressing to obtain a prefabricated body, then a heating wire and a heating wire terminal are placed on the surface of the prefabricated body, and then the remaining part of the pretreated ceramic disc body powder is added, and the first cold isostatic pressing is performed again; the mass of the first part of the pretreated ceramic disc body powder is 69wt% of the total mass of the pretreated ceramic disc body powder;

[0088] (2) The ceramic sleeve raw material is pretreated to obtain a pretreated ceramic sleeve powder; the pretreated ceramic sleeve powder is sequentially subjected to a second cold isostatic pressing process at a pressure of 152 MPa and a holding time of 31 min, a second normal pressure sintering process at a temperature of 1660° C. for 1.1 h, and fine grinding to obtain a ceramic sleeve; the ceramic sleeve raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 2.9wt% of the total mass of the ceramic sleeve raw material;

[0089] The pretreatment in step (1) and step (2) includes wet ball milling at a rotation speed of 153 r / min for 28 hours and drying at a temperature of 62° C. for 12.5 hours, followed by screening using a 90-mesh sieve;

[0090] The mass ratio of the mixed material to the grinding balls in the wet ball mill is 5.5:1; the medium of the wet ball mill includes anhydrous alcohol with a purity of 99.7%; the mass ratio of the mixed material to the medium of the wet ball mill is 1:1.3;

[0091] (3) After the ceramic plate body of step (1) and the ceramic sleeve of step (2) are assembled, a third hot pressing sintering is performed at a temperature of 1880° C. and a pressure of 16.5 MPa for 2.6 hours to achieve the bonding of the ceramic plate body and the ceramic sleeve to obtain the anti-cracking ceramic heating plate.

[0092] The thermal conductivity of the ceramic sleeve in the crack-proof ceramic heating plate prepared in this embodiment is 123 W / m·K, and the thermal conductivity of the ceramic plate body is 218 W / m·K, which is 1.77 times the thermal conductivity of the ceramic sleeve.

[0093] Example 4

[0094] This embodiment provides a method for preparing an anti-cracking ceramic heating plate, the preparation method comprising the following steps:

[0095] (1) The ceramic disc raw material is pretreated to obtain a pretreated ceramic disc powder; the pretreated ceramic disc powder is sequentially subjected to a first cold isostatic pressing process at a pressure of 250 MPa and a holding time of 20 min, a first hot pressing sintering process at a temperature of 1800° C. and a pressure of 10 MPa for 2 h, and fine grinding to obtain a ceramic disc; the ceramic disc raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 2wt% of the total mass of the ceramic disc raw material;

[0096] The first cold isostatic pressing of the pretreated ceramic disc body powder is performed in two steps, firstly, the first part of the pretreated ceramic disc body powder is added and subjected to the first cold isostatic pressing to obtain a prefabricated body, then a heating wire and a heating wire terminal are placed on the surface of the prefabricated body, and then the remaining part of the pretreated ceramic disc body powder is added, and the first cold isostatic pressing is performed again; the mass of the first part of the pretreated ceramic disc body powder is 60wt% of the total mass of the pretreated ceramic disc body powder;

[0097] (2) The ceramic sleeve raw material is pretreated to obtain a pretreated ceramic sleeve powder; the pretreated ceramic sleeve powder is sequentially subjected to a second cold isostatic pressing process at a pressure of 150 MPa and a holding time of 50 min, a second normal pressure sintering process at a temperature of 1600° C. for 1 h, and fine grinding to obtain a ceramic sleeve; the ceramic sleeve raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 3wt% of the total mass of the ceramic sleeve raw material;

[0098] The pretreatment in step (1) and step (2) includes wet ball milling at a rotation speed of 150 r / min for 20 h and drying at a temperature of 60° C. for 12 h, followed by screening using a sieve of 80 mesh;

[0099] The mass ratio of the mixed material to the grinding balls in the wet ball mill is 6:1; the medium of the wet ball mill includes anhydrous alcohol with a purity of 99.7%; the mass ratio of the mixed material to the medium of the wet ball mill is 1:1;

[0100] (3) After the ceramic plate body of step (1) and the ceramic sleeve of step (2) are assembled, a third hot pressing sintering is performed at a temperature of 1750° C. and a pressure of 5 MPa for 1 hour to achieve the bonding of the ceramic plate body and the ceramic sleeve to obtain the anti-cracking ceramic heating plate.

[0101] The thermal conductivity of the ceramic sleeve in the crack-proof ceramic heating plate prepared in this embodiment is 113 W / m·K, and the thermal conductivity of the ceramic plate body is 177 W / m·K, which is 1.57 times the thermal conductivity of the ceramic sleeve.

[0102] Example 5

[0103] This embodiment provides a method for preparing a crack-resistant ceramic heating plate. The preparation method is the same as that of Embodiment 1 except that step (1) does not perform the first hot pressing sintering.

[0104] Example 6

[0105] This embodiment provides a method for preparing a crack-resistant ceramic heating plate. The preparation method is the same as that of Embodiment 1 except that the pressure of the first cold isostatic pressing in step (1) is 150 MPa.

[0106] Example 7

[0107] This embodiment provides a method for preparing a crack-resistant ceramic heating plate. The preparation method is the same as that of Embodiment 1 except that the pressure of the first cold isostatic pressing in step (1) is 300 MPa.

[0108] Example 8

[0109] This embodiment provides a method for preparing a crack-resistant ceramic heating plate. The preparation method is the same as that of Embodiment 1 except that in step (2), the second normal pressure sintering is performed directly without performing the second cold isostatic pressing.

[0110] Example 9

[0111] This embodiment provides a method for preparing an anti-cracking ceramic heating plate. The preparation method is the same as that of Embodiment 1 except that the temperature of the third hot pressing sintering in step (3) is 1500° C.

[0112] Example 10

[0113] This embodiment provides a method for preparing an anti-cracking ceramic heating plate. The preparation method is the same as that of Embodiment 1 except that the temperature of the third hot pressing sintering in step (3) is 2000°C.

[0114] Embodiment 11

[0115] This embodiment provides a method for preparing a crack-resistant ceramic heating plate. The preparation method is the same as that of Embodiment 1 except that the pressure of the third normal pressure sintering in step (3) is 3 MPa.

[0116] Example 12

[0117] This embodiment provides a method for preparing a crack-resistant ceramic heating plate. The preparation method is the same as that of Embodiment 1 except that the pressure of the third normal pressure sintering in step (3) is 23 MPa.

[0118] Comparative Example 1

[0119] This comparative example provides a method for preparing a crack-resistant ceramic heating plate, which is the same as Example 1 except that in step (1), the Y2O3 powder in the ceramic plate body raw material accounts for 1wt% of the total mass of the ceramic plate body raw material.

[0120] Comparative Example 2

[0121] This comparative example provides a method for preparing a crack-resistant ceramic heating plate, which is the same as Example 1 except that in step (1), the Y2O3 powder in the ceramic plate body raw material accounts for 6wt% of the total mass of the ceramic plate body raw material.

[0122] Comparative Example 3

[0123] This comparative example provides a method for preparing a crack-resistant ceramic heating plate, which is the same as Example 1 except that in step (2), the Y2O3 powder in the ceramic sleeve raw material accounts for 0.5wt% of the total mass of the ceramic sleeve raw material.

[0124] Comparative Example 4

[0125] This comparative example provides a method for preparing a crack-resistant ceramic heating plate, which is the same as Example 1 except that in step (2), the Y2O3 powder in the ceramic sleeve raw material accounts for 4wt% of the total mass of the ceramic sleeve raw material.

[0126] The ceramic heating plate products obtained in the above-mentioned embodiments and comparative examples were tested by repeatedly heating to 450° C. for 100 times and then cooling down. The results of whether the ceramic heating plate products were cracked are shown in Table 1.

[0127] Table 1

[0128] Whether it is cracked Example 1 no Example 2 no Example 3 no Example 4 no Example 5 yes Example 6 yes Example 7 yes Example 8 yes Example 9 no Example 10 yes Embodiment 11 yes Example 12 yes Comparative Example 1 yes Comparative Example 2 yes Comparative Example 3 yes Comparative Example 4 yes

[0129] From Table 1 we can see that:

[0130] (1) It can be seen from Examples 1 to 4 that the preparation method of the anti-cracking ceramic heating plate provided by the present invention controls the thermal conductivity of the ceramic sleeve to be 91 to 123 W / m·K, and the thermal conductivity of the ceramic plate body to be 177 to 225 W / m·K, and the obtained anti-cracking ceramic heating plate product will not crack;

[0131] (2) Combining Example 1 with Examples 5 to 7, it can be seen that the first hot pressing sintering is not performed in step (1) of Example 5, the first cold isostatic pressing pressure in step (1) of Example 6 is relatively low, and the first cold isostatic pressing pressure in step (1) of Example 7 is relatively high, all of which will result in the ceramic plate body not being formed and the obtained ceramic heating plate product will crack;

[0132] (3) Combining Example 1 and Example 8, it can be seen that in Example 8, step (2) without performing the second cold isostatic pressing and directly performing the second normal pressure sintering will result in the ceramic sleeve not being formed and the obtained ceramic heating plate product will crack;

[0133] (4) Combining Example 1 with Examples 9 to 12, it can be seen that the temperature of the third hot pressing sintering in step (3) of Example 9 is relatively low, which will result in the disc body and the sleeve not being able to achieve a good connection, the weld sealing is poor, the connection strength is low, and the leakage rate of the obtained ceramic heating disc product is unqualified; the temperature of the third hot pressing sintering in step (3) of Example 10 is relatively high, which will result in the abnormal growth of the disc body grain size, the reduction of the disc body thermal conductivity, and the obtained ceramic heating disc product will crack; the pressure of the third hot pressing sintering in step (3) of Example 11 is relatively low, which will result in the disc body and the sleeve connecting surface not being able to fit tightly during the sintering process, resulting in poor welding quality, poor air tightness, low connection strength, and the obtained ceramic heating disc product will crack, and the leakage rate is unqualified; the pressure of the third hot pressing sintering in step (3) of Example 12 is relatively high, which will result in cracks in the sleeve during the pressure process, causing damage, deformation of the disc body during the sintering process, and the obtained ceramic heating disc product will crack;

[0134] (5) Combining Example 1 with Comparative Examples 1 to 4, it can be seen that in step (1) of Comparative Example 1, the proportion of Y2O3 powder in the ceramic disc raw material to the total mass of the ceramic disc raw material is relatively low, the thermal conductivity of the ceramic disc is 56 W / m·K, and the thermal conductivity of the ceramic sleeve is 97 W / m·K. The thermal conductivities of the two are close, and there is a lot of heat diffusion from the ceramic disc to the ceramic sleeve. The surface temperature uniformity of the ceramic disc is poor, and the central part of the ceramic disc will crack. In step (1) of Comparative Example 2, the proportion of Y2O3 powder in the ceramic disc raw material is relatively high, the thermal conductivity of the ceramic disc is 251 W / m·K, and the thermal conductivity of the ceramic sleeve is 99 W / m·K. Since the thermal expansion coefficient is positively correlated with the thermal conductivity, the thermal expansion coefficient of the ceramic disc and the ceramic sleeve is positively correlated. The difference in coefficients is too large, and the ceramic disc is damaged; similarly, in the step (2) of comparative example 3, the proportion of Y2O3 powder in the ceramic sleeve raw material to the total mass of the ceramic sleeve raw material is low, the thermal conductivity of the ceramic disc is 185W / m·K, and the thermal conductivity of the ceramic sleeve is 43W / m·K. The difference in thermal expansion coefficients between the two is too large, and the ceramic disc is damaged; in the step (2) of comparative example 4, the proportion of Y2O3 powder in the ceramic sleeve raw material to the total mass of the ceramic sleeve raw material is high, the thermal conductivity of the ceramic disc is 187W / m·K, and the thermal conductivity of the ceramic sleeve is 197W / m·K. The thermal conductivities of the two are close, there is more heat diffusion from the ceramic disc to the ceramic sleeve, the surface temperature uniformity of the ceramic disc is poor, and the central part of the ceramic disc will crack.

[0135] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a crack-resistant ceramic heating plate, characterized in that: The preparation method comprises the following steps: (1) The ceramic disc raw material is pretreated to obtain a pretreated ceramic disc powder; the pretreated ceramic disc powder is sequentially subjected to a first cold isostatic pressing, a first hot pressing sintering and mechanical processing to obtain a ceramic disc; the ceramic disc raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 2wt% to 5wt% of the total mass of the ceramic disc raw material; During the first cold isostatic pressing process, a heating wire and a heating wire terminal are placed; (2) The ceramic sleeve raw material is pretreated to obtain a pretreated ceramic sleeve powder; the pretreated ceramic sleeve powder is sequentially subjected to a second cold isostatic pressing, a second normal pressure sintering and mechanical processing to obtain a ceramic sleeve; the ceramic sleeve raw material includes AlN powder and Y2O3 powder; the Y2O3 powder accounts for 1wt% to 3wt% of the total mass of the ceramic sleeve raw material; (3) After the ceramic plate body described in step (1) and the ceramic sleeve described in step (2) are assembled, they are subjected to a third hot pressing sintering process to achieve bonding of the ceramic plate body and the ceramic sleeve to obtain an anti-cracking ceramic heating plate.

2. The preparation method according to claim 1, characterized in that: Step (1) The pressure of the first cold isostatic pressing is 200-250 MPa; Preferably, the holding time of the first cold isostatic pressing is 20 to 30 minutes.

3. The preparation method according to claim 1 or 2, characterized in that: The first cold isostatic pressing of the pretreated ceramic disc powder in step (1) is performed twice, firstly adding the first part of the pretreated ceramic disc powder and performing the first cold isostatic pressing to obtain a prefabricated body, then placing a heating wire and a heating wire terminal on the surface of the prefabricated body, adding the remaining part of the pretreated ceramic disc powder, and performing the first cold isostatic pressing again; Preferably, the mass of the first part of the pretreated ceramic disc powder is 60wt% to 70wt% of the total mass of the pretreated ceramic disc powder.

4. The preparation method according to any one of claims 1 to 3, characterized in that: Step (1) The temperature of the first hot pressing sintering is 1600-1800° C.; Preferably, the pressure of the first hot pressing sintering is 10-30 MPa; Preferably, the first hot pressing sintering time is 2 to 5 hours.

5. The preparation method according to any one of claims 1 to 4, characterized in that: Step (2) The pressure of the second cold isostatic pressing is 150 to 250 MPa; Preferably, the holding time of the second cold isostatic pressing is 30 to 50 minutes.

6. The preparation method according to any one of claims 1 to 5, characterized in that: Step (2) The temperature of the second pressureless sintering is 1600-1800° C.; Preferably, the second pressureless sintering time is 1 to 4 hours.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The pretreatment in step (1) and step (2) comprises wet ball milling, drying and screening in sequence; Preferably, the mass ratio of the mixed material to the grinding balls in the wet ball milling is (2-6):1; Preferably, the medium of the wet ball milling comprises anhydrous alcohol with a purity of 99.7%; Preferably, the mass ratio of the mixed material and the medium in the wet ball milling is 1:(1-1.5); Preferably, the rotation speed of the wet ball mill is 150-300 r / min; Preferably, the wet ball milling time is 20 to 30 hours; Preferably, the drying temperature is 60-80°C; Preferably, the drying time is 12 to 18 hours; Preferably, the screening is performed using a sieve with a mesh size of 80 to 120.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The mechanical processing in step (1) and step (2) includes fine grinding.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The temperature of the third hot pressing sintering in step (3) is 1750-1900° C. Preferably, the pressure of the third hot pressing sintering is 5 to 20 MPa; Preferably, the third hot pressing sintering time is 1 to 4 hours.

10. A crack-proof ceramic heating plate, characterized in that: The anti-cracking ceramic heating plate is prepared by the method for preparing the anti-cracking ceramic heating plate according to any one of claims 1 to 9; The anti-cracking ceramic heating plate comprises a ceramic plate body and a ceramic sleeve which are combined with each other; A heating wire is arranged in the ceramic disc body; the heating wire is connected to the heating wire terminal; A heating rod is arranged in the ceramic sleeve; the heating rod is connected to the heating wire terminal.

Images