Ceramic heating body and preparation method and application thereof

Abstract

The invention relates to a ceramic heating body and a preparation method and application thereof, in particular to the technical field of heating equipment, and the ceramic heating body comprises a first ceramic layer, a heating layer, a second ceramic layer, a radio frequency net layer and a third ceramic layer which are sequentially arranged; the thickness of the first ceramic layer is larger than that of the second ceramic layer and larger than that of the third ceramic layer; the first ceramic layer, the second ceramic layer and the third ceramic layer are prepared from the following raw materials: aluminum nitride powder, yttrium oxide powder, an adhesive, a plasticizer and alcohol. According to the ceramic heating body provided by the invention, by designing the structure and the composition of the ceramic heating body, the surface temperature uniformity and the heat conductivity of the ceramic heating body are effectively improved, the use performance of the ceramic heating body is remarkably improved, meanwhile, the efficiency of the heating process is also improved, and efficient heating of a workpiece is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of heating equipment, and in particular to a ceramic heating body and a preparation method and application thereof. Background Art

[0002] At present, aluminum nitride ceramics are widely used in fast-growing fields such as semiconductors, intelligent power components, automotive electronics, and solar energy due to their excellent heat dissipation, stability, and insulation. In the semiconductor manufacturing process, aluminum nitride ceramic heaters are needed to heat the wafers, so that CVD has better effects and obtains more uniform films.

[0003] Aluminum nitride ceramics have high hardness and great brittleness, so complex components are mostly made separately and then connected by welding. The aluminum nitride ceramic heater is mainly composed of a heating plate body and a sleeve. The plate body mainly contacts the wafer, and is embedded with components such as a radio frequency mesh and a heating wire.

[0004] CN114150295A provides a method for preparing a ceramic heater, wherein the ceramic raw material powder is pre-pressed at room temperature, and the radio frequency electrode, the heating component and the ceramic raw material powder are pre-formed, and then hot-pressed with the fired ceramic tube to form a ceramic heating plate, which is formed by a single high-temperature firing.

[0005] KR101333629B1 provides a method for preparing a ceramic heating plate, wherein ceramic raw material powder, a radio frequency net, and a heating wire are directly loaded into a mold at room temperature for hot pressing and sintering to obtain a ceramic heating plate.

[0006] However, the existing ceramic heaters still have certain defects in the preparation process. For example, powder is used for pre-pressing to obtain a low-density blank, and the RF mesh and heating wire are directly loaded into the mold for disc sintering. The flatness of the RF mesh inside the disc is difficult to control, and the position of the heating wire has a large deviation from the designed position, resulting in poor temperature uniformity of the disc, and the disc is prone to internal defects, resulting in poor surface temperature uniformity and thermal conductivity of the obtained ceramic heater. Summary of the invention

[0007] In view of the problems existing in the prior art, an object of the present invention is to provide a ceramic heater and a preparation method and use thereof, so as to solve the problems of poor surface temperature uniformity and thermal conductivity of the ceramic heater.

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

[0009] In a first aspect, the present invention provides a ceramic heater, the ceramic heater comprising a first ceramic layer, a heating layer, a second ceramic layer, a radio frequency mesh layer and a third ceramic layer arranged in sequence;

[0010] The thickness of the first ceramic layer>the thickness of the second ceramic layer>the thickness of the third ceramic layer;

[0011] The raw materials for preparing the first ceramic layer, the second ceramic layer and the third ceramic layer include aluminum nitride powder, yttrium oxide powder, an adhesive, a plasticizer and alcohol.

[0012] The ceramic heater provided by the present invention achieves effective improvement of the surface temperature uniformity and thermal conductivity of the ceramic heater by designing the structure and composition of the ceramic heater, significantly improves the performance of the ceramic heater, and also improves the efficiency of the heating process, which is conducive to achieving efficient heating of the workpiece.

[0013] As a preferred technical solution of the present invention, the thickness of the first ceramic layer is 12-30 mm.

[0014] Preferably, the second ceramic layer has a thickness of 9-24 mm.

[0015] Preferably, the thickness of the third ceramic layer is 3-9 mm.

[0016] As a preferred technical solution of the present invention, the raw materials for preparing the first ceramic layer, the second ceramic layer and the third ceramic layer include 90-100 parts of aluminum nitride powder, 4-6 parts of yttrium oxide powder, 8-12 parts of adhesive, 4-7 parts of plasticizer and 90-110 parts of alcohol in parts by weight.

[0017] As a preferred technical solution of the present invention, the adhesive includes polyvinyl butyral.

[0018] Preferably, the plasticizer comprises dibutyl phthalate.

[0019] Preferably, the alcohol includes one or a combination of at least two of methanol, ethanol or ethylene glycol.

[0020] In a second aspect, the present invention provides a method for preparing the ceramic heating body according to the first aspect, the preparation method comprising:

[0021] Aluminum nitride powder, yttrium oxide powder, adhesive, plasticizer and alcohol are mixed and stirred, and then cast to obtain a green sheet;

[0022] The obtained green sheets are used to prepare a first ceramic layer, a second ceramic layer and a third ceramic layer respectively;

[0023] The first ceramic layer, the heating layer, the second ceramic layer, the radio frequency network layer and the third ceramic layer are assembled in sequence and then subjected to a hot pressing treatment, and then a first heat treatment and a second heat treatment are sequentially performed to obtain a ceramic heating body.

[0024] As a preferred technical solution of the present invention, the thickness of the obtained green sheet is 0.3-0.6 mm.

[0025] Preferably, the first ceramic layer is prepared by stacking 40-50 green sheets.

[0026] Preferably, the second ceramic layer is prepared by stacking 30-40 green sheets.

[0027] Preferably, the third ceramic layer is prepared by laminating 10-15 green sheets.

[0028] As a preferred technical solution of the present invention, the temperature of the hot pressing treatment is 100-120°C.

[0029] Preferably, the pressure of the hot pressing treatment is 50-80t.

[0030] Preferably, the heat pressing treatment time is ≥ 1 h.

[0031] As a preferred technical solution of the present invention, the temperature of the first heat treatment is 550-650°C.

[0032] Preferably, the first heat treatment is performed under a protective atmosphere.

[0033] Preferably, the first heat treatment is performed for 12-18 hours.

[0034] As a preferred technical solution of the present invention, the temperature of the second heat treatment is 1750-1850°C.

[0035] Preferably, the second heat treatment is performed under a protective atmosphere.

[0036] Preferably, the pressure of the second heat treatment is 18-25 MPa.

[0037] Preferably, the second heat treatment time is 2-4 hours.

[0038] In a third aspect, the present invention provides a use of the ceramic heating body as described in the first aspect, wherein the use comprises using the ceramic heating body to prepare an aluminum nitride ceramic heater.

[0039] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0040] The ceramic heater provided by the present invention adopts a specific ceramic layer design to improve the heating performance of the ceramic heater. The thermal conductivity of the obtained ceramic heater is ≥268.5W / mK and the temperature distribution coefficient is ≤0.21, which is conducive to the efficient and uniform heating of the workpiece by the ceramic heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of a ceramic heating body provided by an embodiment of the present invention.

[0042] In the figure: 1-first ceramic layer, 2-heating layer, 3-second ceramic layer, 4-RF mesh layer, 5-third ceramic layer.

[0043] 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. DETAILED DESCRIPTION

[0044] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0045] This embodiment provides a ceramic heating body, such as Figure 1 As shown, the ceramic heating body comprises a first ceramic layer 1, a heating layer 2, a second ceramic layer 3, a radio frequency mesh layer 4 and a third ceramic layer 5 which are arranged in sequence;

[0046] The thickness of the first ceramic layer 1 is greater than the thickness of the second ceramic layer 3 and greater than the thickness of the third ceramic layer 5;

[0047] The raw materials for preparing the first ceramic layer 1 , the second ceramic layer 3 and the third ceramic layer 5 include aluminum nitride, yttrium oxide, an adhesive, a plasticizer and alcohol.

[0048] Among them, the thickness of the first ceramic layer 1 is 12-30mm, for example, it can be 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm or 30mm, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0049] The thickness of the second ceramic layer 3 is 9-24 mm, for example, 9 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm, 22 mm or 24 mm, but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0050] The thickness of the third ceramic layer 5 is 3-9 mm, for example, 3 mm, 6 mm, 7 mm, 8 mm or 9 mm, but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0051] In the present invention, the thickness of the heating layer 2 can be selected according to conventional designs in the art, such as heating temperature, heating power and other indicators. Exemplarily, the thickness of the heating layer 2 is 20-26 mm.

[0052] In the present invention, the thickness of the radio frequency mesh layer 4 can be selected according to conventional designs in the art. Exemplarily, the thickness of the radio frequency mesh layer 4 is 3-8 mm.

[0053] Specifically, the raw materials for preparing the first ceramic layer 1, the second ceramic layer 3 and the third ceramic layer 5 include, by weight, 90-100 parts of aluminum nitride powder, 4-6 parts of yttrium oxide powder, 8-12 parts of adhesive, 4-7 parts of plasticizer and 90-110 parts of alcohol.

[0054] Among them, the aluminum nitride powder in the preparation raw materials of the first ceramic layer 1, the second ceramic layer 3 and the third ceramic layer 5 is 90-100 parts by weight, for example, it can be 90 parts, 91 parts, 92 parts, 93 parts, 94 parts, 95 parts, 96 parts, 97 parts, 98 parts, 99 parts or 100 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0055] Among them, the yttrium oxide powder in the preparation raw materials of the first ceramic layer 1, the second ceramic layer 3 and the third ceramic layer 5 is 4-6 parts by weight, for example, it can be 4 parts, 4.2 parts, 4.4 parts, 4.6 parts, 4.8 parts, 5 parts, 5.2 parts, 5.4 parts, 5.6 parts, 5.8 parts or 6 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0056] Among them, the adhesive in the preparation raw materials of the first ceramic layer 1, the second ceramic layer 3 and the third ceramic layer 5 is 8-12 parts by weight, for example, it can be 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, 10.5 parts, 11 parts, 11.5 parts or 12 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0057] Among them, the plasticizer in the preparation raw materials of the first ceramic layer 1, the second ceramic layer 3 and the third ceramic layer 5 is 4-7 parts by weight, for example, it can be 4 parts, 4.5 parts, 6 parts, 6.5 parts or 7 parts, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0058] Among them, the alcohol content in the raw materials for preparing the first ceramic layer 1, the second ceramic layer 3 and the third ceramic layer 5 is 90-110 parts by weight, for example, it can be 90 parts, 92 parts, 94 parts, 96 parts, 98 parts, 100 parts, 102 parts, 104 parts, 106 parts, 108 parts or 110 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0059] Wherein, the adhesive comprises polyvinyl butyral.

[0060] In the present invention, the weight average molecular weight of the polyvinyl butyral used is 10,000-30,000.

[0061] Wherein, the plasticizer includes dibutyl phthalate.

[0062] The alcohol includes one or a combination of at least two of methanol, ethanol or ethylene glycol.

[0063] In the present invention, the average particle size of the aluminum nitride powder is less than 0.5 μm.

[0064] In the present invention, the average particle size of the yttrium oxide powder is 4-20 μm.

[0065] Furthermore, the present invention provides a method for preparing the aforementioned ceramic heating body, the preparation method comprising:

[0066] Aluminum nitride powder, yttrium oxide powder, adhesive, plasticizer and alcohol are mixed and stirred, and then cast to obtain a green sheet;

[0067] The obtained green sheets are used to prepare a first ceramic layer 1, a second ceramic layer 3 and a third ceramic layer 5 respectively;

[0068] The first ceramic layer 1, the heating layer 2, the second ceramic layer 3, the radio frequency network layer 4 and the third ceramic layer 5 are assembled in sequence and then subjected to a hot pressing treatment, and then subjected to a first heat treatment and a second heat treatment in sequence to obtain a ceramic heating body.

[0069] The thickness of the obtained green sheet is 0.3-0.6 mm, for example, it can be 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm or 0.6 mm, but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0070] Among them, the first ceramic layer 1 is prepared by stacking 40-50 green sheets, for example, it can be 40, 41, 42, 43, 44, 45, 46, 47, 48, 49 or 50, etc., but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0071] Among them, the second ceramic layer 3 is prepared by stacking 30-40 green sheets, for example, it can be 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0072] The third ceramic layer 5 is prepared by stacking 10-15 green sheets, for example, 10, 11, 12, 13, 14 or 15 green sheets, but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0073] The temperature of the hot pressing treatment is 100-120°C, for example, it can be 100°C, 102°C, 104°C, 106°C, 108°C, 110°C, 112°C, 114°C, 116°C, 118°C or 120°C, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0074] Among them, the pressure of the hot pressing treatment is 50-80t, for example, it can be 50t, 52t, 54t, 56t, 58t, 60t, 62t, 64t, 66t, 68t, 70t, 72t, 74t, 76t, 78t or 80t, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0075] The time of the hot pressing treatment is ≥1h, for example, it can be 1h, 1.5h, 2h, 2.5h or 3h, but is not limited to the listed values. Other values ​​not listed within the range also meet the requirements.

[0076] Among them, the temperature of the first heat treatment is 550-650℃, for example, it can be 550℃, 560℃, 570℃, 580℃, 590℃, 600℃, 610℃, 620℃, 630℃, 640℃ or 650℃, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0077] Wherein, the first heat treatment is performed under a protective atmosphere.

[0078] Among them, the time of the first heat treatment is 12-18h, for example, it can be 12h, 12.5h, 13h, 13.5h, 14h, 14.5h, 15h, 15.5h, 16h, 16.5h, 17h, 17.5h or 18h, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0079] Among them, the temperature of the second heat treatment is 1750-1850℃, for example, it can be 1750℃, 1760℃, 1770℃, 1780℃, 1790℃, 1800℃, 1810℃, 1820℃, 1830℃, 1840℃ or 1850℃, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0080] Wherein, the second heat treatment is performed under a protective atmosphere.

[0081] Among them, the pressure of the second heat treatment is 18-25MPa, for example, it can be 18MPa, 18.5MPa, 19MPa, 19.5MPa, 20MPa, 20.5MPa, 21MPa, 21.5MPa, 22MPa, 22.5MPa, 23MPa, 23.5MPa, 24MPa, 24.5MPa or 25MPa, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0082] The time of the second heat treatment is 2-4 hours, for example, it can be 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, but is not limited to the listed values. Other values ​​not listed within the range also meet the requirements.

[0083] In the present invention, the protective atmosphere in the heat treatment includes nitrogen, helium, neon, argon and other commonly used protective gases in the art to prevent impurity gases from affecting the performance of the obtained product.

[0084] Further, in order to illustrate the thermal conductivity of the ceramic heater provided by the present invention, an actual example is used for illustration, as follows:

[0085] Example 1

[0086] This embodiment provides a ceramic heater, which comprises a first ceramic layer 1, a heating layer 2, a second ceramic layer 3, a radio frequency mesh layer 4 and a third ceramic layer 5 arranged in sequence;

[0087] The thickness of the first ceramic layer 1 is greater than the thickness of the second ceramic layer 3 and greater than the thickness of the third ceramic layer 5;

[0088] The raw materials for preparing the first ceramic layer 1, the second ceramic layer 3 and the third ceramic layer 5 include, by weight, 94 parts of aluminum nitride powder (average particle size of 0.1 μm), 5 parts of yttrium oxide powder (average particle size of 10 μm), 9 parts of adhesive, 5 parts of plasticizer and 100 parts of alcohol; the thickness of the first ceramic layer 1 is 17.6 mm; the thickness of the second ceramic layer 3 is 15.84 mm; the thickness of the third ceramic layer 5 is 4.8 mm; the adhesive is polyvinyl butyral (weight average molecular weight of 20,000); the plasticizer is dibutyl phthalate; the alcohol is ethanol;

[0089] The thickness of the heating layer 2 is 22 mm; the thickness of the radio frequency mesh layer 4 is 5 mm;

[0090] The preparation process is as follows:

[0091] Aluminum nitride powder, yttrium oxide powder, adhesive, plasticizer and alcohol are mixed and stirred, and then cast to obtain a green sheet;

[0092] The obtained green sheets are used to prepare a first ceramic layer 1, a second ceramic layer 3 and a third ceramic layer 5 respectively;

[0093] The first ceramic layer 1, the heating layer 2, the second ceramic layer 3, the radio frequency network layer 4 and the third ceramic layer 5 are assembled in sequence and then subjected to a hot pressing treatment, and then subjected to a first heat treatment and a second heat treatment in sequence to obtain a ceramic heating body.

[0094] The thickness of the obtained green sheets is 0.4 mm; the first ceramic layer 1 is prepared by laminating 44 green sheets; the second ceramic layer 3 is prepared by laminating 36 green sheets; the third ceramic layer 5 is prepared by laminating 12 green sheets;

[0095] The temperature of the hot pressing treatment is 110°C; the pressure of the hot pressing treatment is 70t; and the time of the hot pressing treatment is 1h;

[0096] The temperature of the first heat treatment is 600° C.; the first heat treatment is performed under a protective atmosphere (nitrogen); the time of the first heat treatment is 14 hours;

[0097] The temperature of the second heat treatment is 1800° C.; the second heat treatment is performed under a protective atmosphere (nitrogen); the pressure of the second heat treatment is 20 MPa; and the time of the second heat treatment is 3 hours.

[0098] Example 2

[0099] This embodiment provides a ceramic heater, which comprises a first ceramic layer 1, a heating layer 2, a second ceramic layer 3, a radio frequency mesh layer 4 and a third ceramic layer 5 arranged in sequence;

[0100] The thickness of the first ceramic layer 1 is greater than the thickness of the second ceramic layer 3 and greater than the thickness of the third ceramic layer 5;

[0101] The raw materials for preparing the first ceramic layer 1, the second ceramic layer 3 and the third ceramic layer 5 include, by weight, 97 parts of aluminum nitride powder (average particle size of 0.2 μm), 5 parts of yttrium oxide powder (average particle size of 15 μm), 10 parts of adhesive, 6 parts of plasticizer and 100 parts of alcohol; the thickness of the first ceramic layer 1 is 23.5 mm; the thickness of the second ceramic layer 3 is 16.5 mm; the thickness of the third ceramic layer 5 is 7 mm; the adhesive is polyvinyl butyral (weight average molecular weight of 25000); the plasticizer is dibutyl phthalate; the alcohol is ethanol;

[0102] The thickness of the heating layer 2 is 24 mm; the thickness of the radio frequency mesh layer 4 is 6 mm;

[0103] The preparation process is as follows:

[0104] Aluminum nitride powder, yttrium oxide powder, adhesive, plasticizer and alcohol are mixed and stirred, and then cast to obtain a green sheet;

[0105] The obtained green sheets are used to prepare a first ceramic layer 1, a second ceramic layer 3 and a third ceramic layer 5 respectively;

[0106] The first ceramic layer 1, the heating layer 2, the second ceramic layer 3, the radio frequency network layer 4 and the third ceramic layer 5 are assembled in sequence and then subjected to a hot pressing treatment, and then subjected to a first heat treatment and a second heat treatment in sequence to obtain a ceramic heating body.

[0107] The thickness of the obtained green sheets is 0.5 mm; the first ceramic layer 1 is prepared by laminating 47 green sheets; the second ceramic layer 3 is prepared by laminating 33 green sheets; the third ceramic layer 5 is prepared by laminating 14 green sheets;

[0108] The temperature of the hot pressing treatment is 115°C; the pressure of the hot pressing treatment is 60t; and the time of the hot pressing treatment is 2h;

[0109] The temperature of the first heat treatment is 625° C.; the first heat treatment is performed under a protective atmosphere (argon); the time of the first heat treatment is 16 hours;

[0110] The temperature of the second heat treatment is 1820° C.; the second heat treatment is performed under a protective atmosphere (argon); the pressure of the second heat treatment is 22 MPa; and the time of the second heat treatment is 3.5 h.

[0111] Example 3

[0112] This embodiment provides a ceramic heater, which comprises a first ceramic layer 1, a heating layer 2, a second ceramic layer 3, a radio frequency mesh layer 4 and a third ceramic layer 5 arranged in sequence;

[0113] The thickness of the first ceramic layer 1 is greater than the thickness of the second ceramic layer 3 and greater than the thickness of the third ceramic layer 5;

[0114] The raw materials for preparing the first ceramic layer 1, the second ceramic layer 3 and the third ceramic layer 5 include, by weight, 100 parts of aluminum nitride powder (average particle size of 0.3 μm), 4 parts of yttrium oxide powder (average particle size of 20 μm), 12 parts of adhesive, 4 parts of plasticizer and 110 parts of alcohol; the thickness of the first ceramic layer 1 is 30 mm; the thickness of the second ceramic layer 3 is 24 mm; the thickness of the third ceramic layer 5 is 9 mm; the adhesive is polyvinyl butyral (weight average molecular weight of 30,000); the plasticizer is dibutyl phthalate; the alcohol is methanol;

[0115] The thickness of the heating layer 2 is 26 mm; the thickness of the radio frequency mesh layer 4 is 8 mm;

[0116] The preparation process is as follows:

[0117] Aluminum nitride powder, yttrium oxide powder, adhesive, plasticizer and alcohol are mixed and stirred, and then cast to obtain a green sheet;

[0118] The obtained green sheets are used to prepare a first ceramic layer 1, a second ceramic layer 3 and a third ceramic layer 5 respectively;

[0119] The first ceramic layer 1, the heating layer 2, the second ceramic layer 3, the radio frequency network layer 4 and the third ceramic layer 5 are assembled in sequence and then subjected to a hot pressing treatment, and then subjected to a first heat treatment and a second heat treatment in sequence to obtain a ceramic heating body.

[0120] The thickness of the obtained green sheets is 0.6 mm; the first ceramic layer 1 is prepared by laminating 50 green sheets; the second ceramic layer 3 is prepared by laminating 40 green sheets; the third ceramic layer 5 is prepared by laminating 15 green sheets;

[0121] The temperature of the hot pressing treatment is 120°C; the pressure of the hot pressing treatment is 50t; and the time of the hot pressing treatment is 2h;

[0122] The temperature of the first heat treatment is 550° C.; the first heat treatment is performed under a protective atmosphere (nitrogen); the time of the first heat treatment is 12 hours;

[0123] The temperature of the second heat treatment is 1850° C.; the second heat treatment is performed under a protective atmosphere (nitrogen); the pressure of the second heat treatment is 18 MPa; and the time of the second heat treatment is 4 hours.

[0124] Example 4

[0125] This embodiment provides a ceramic heater, which comprises a first ceramic layer 1, a heating layer 2, a second ceramic layer 3, a radio frequency mesh layer 4 and a third ceramic layer 5 arranged in sequence;

[0126] The thickness of the first ceramic layer 1 is greater than the thickness of the second ceramic layer 3 and greater than the thickness of the third ceramic layer 5;

[0127] The raw materials for preparing the first ceramic layer 1, the second ceramic layer 3 and the third ceramic layer 5 include, by weight, 90 parts of aluminum nitride powder (average particle size of 0.4 μm), 6 parts of yttrium oxide powder (average particle size of 4 μm), 8 parts of adhesive, 7 parts of plasticizer and 90 parts of alcohol; the thickness of the first ceramic layer 1 is 12 mm; the thickness of the second ceramic layer 3 is 9 mm; the thickness of the third ceramic layer 5 is 3 mm; the adhesive is polyvinyl butyral (weight average molecular weight of 10,000); the plasticizer is dibutyl phthalate; the alcohol is ethanol;

[0128] The thickness of the heating layer 2 is 20 mm; the thickness of the radio frequency mesh layer 4 is 3 mm;

[0129] The preparation process is as follows:

[0130] Aluminum nitride powder, yttrium oxide powder, adhesive, plasticizer and alcohol are mixed and stirred, and then cast to obtain a green sheet;

[0131] The obtained green sheets are used to prepare a first ceramic layer 1, a second ceramic layer 3 and a third ceramic layer 5 respectively;

[0132] The first ceramic layer 1, the heating layer 2, the second ceramic layer 3, the radio frequency network layer 4 and the third ceramic layer 5 are assembled in sequence and then subjected to a hot pressing treatment, and then subjected to a first heat treatment and a second heat treatment in sequence to obtain a ceramic heating body.

[0133] The thickness of the obtained green sheets is 0.3 mm; the first ceramic layer 1 is prepared by laminating 40 green sheets; the second ceramic layer 3 is prepared by laminating 30 green sheets; the third ceramic layer 5 is prepared by laminating 10 green sheets;

[0134] The temperature of the hot pressing treatment is 100°C; the pressure of the hot pressing treatment is 80t; the time of the hot pressing treatment is 1.5h;

[0135] The temperature of the first heat treatment is 650° C.; the first heat treatment is performed under a protective atmosphere (nitrogen); the time of the first heat treatment is 18 hours;

[0136] The temperature of the second heat treatment is 1750° C.; the second heat treatment is performed under a protective atmosphere (nitrogen); the pressure of the second heat treatment is 25 MPa; and the time of the second heat treatment is 2 hours.

[0137] Comparative Example 1

[0138] The only difference from Example 1 is that the thickness of the first ceramic layer is 15.84 mm.

[0139] Comparative Example 2

[0140] The only difference from Example 1 is that the thickness of the second ceramic layer is 17.6 mm.

[0141] Comparative Example 3

[0142] The only difference from Example 1 is that the thickness of the first ceramic layer is 4.8 mm.

[0143] Comparative Example 4

[0144] The only difference from Example 1 is that yttrium oxide powder is not added during the preparation of the ceramic layer.

[0145] Comparative Example 5

[0146] The only difference from Example 1 is that during the preparation of the ceramic layer, the yttrium oxide powder is replaced by zirconium oxide powder of equal amount and particle size.

[0147] Comparative Example 6

[0148] The only difference from Example 1 is that during the preparation of the ceramic layer, the yttrium oxide powder is replaced by lanthanum oxide powder of equal amount and particle size.

[0149] Comparative Example 7

[0150] The only difference from Example 1 is that during the preparation of the ceramic layer, the weight portion of yttrium oxide powder is reduced to 2 parts.

[0151] Comparative Example 8

[0152] The only difference from Example 1 is that during the preparation of the ceramic layer, the weight portion of yttrium oxide powder is 10 parts.

[0153] The ceramic heating bodies obtained in Examples 1-4 and Comparative Examples 1-8 were subjected to thermal performance tests, specifically surface temperature uniformity test (GB / T 7287-2008 Test method for infrared radiation heaters, Section 8 Measurement method for heater surface temperature distribution) and thermal conductivity test (GB / T 39862-2021 Test of thermal conductivity of high thermal conductivity ceramics). The test results are detailed in Table 1.

[0154] Table 1

[0155] Temperature distribution coefficient Thermal conductivity / W / mK Example 1 0.12 284.5 Example 2 0.11 278.6 Example 3 0.18 268.5 Example 4 0.21 272.6 Comparative Example 1 0.55 168.5 Comparative Example 2 0.35 175.6 Comparative Example 3 0.43 186.5 Comparative Example 4 0.53 178.9 Comparative Example 5 0.36 252.3 Comparative Example 6 0.34 241.3 Comparative Example 7 0.38 226.5 Comparative Example 8 0.36 246.3

[0156] As can be seen from Table 1, in the solution provided by the present invention, by designing the structure and composition of the ceramic heater, the surface temperature uniformity and thermal conductivity of the ceramic heater are effectively improved, the performance of the ceramic heater is significantly improved, and the efficiency of the heating process is also improved, which is conducive to achieving efficient heating of the workpiece.

[0157] It is stated that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0158] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0159] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0160] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A ceramic heating element, characterized in that: The ceramic heating body comprises a first ceramic layer, a heating layer, a second ceramic layer, a radio frequency mesh layer and a third ceramic layer which are arranged in sequence; The thickness of the first ceramic layer>the thickness of the second ceramic layer>the thickness of the third ceramic layer; The raw materials for preparing the first ceramic layer, the second ceramic layer and the third ceramic layer include aluminum nitride powder, yttrium oxide powder, an adhesive, a plasticizer and alcohol.

2. The ceramic heating element according to claim 1, characterized in that: The thickness of the first ceramic layer is 12-30 mm; Preferably, the thickness of the second ceramic layer is 9-24 mm; Preferably, the thickness of the third ceramic layer is 3-9 mm.

3. The ceramic heating body according to claim 1 or 2, characterized in that: The raw materials for preparing the first ceramic layer, the second ceramic layer and the third ceramic layer include, by weight, 90-100 parts of aluminum nitride powder, 4-6 parts of yttrium oxide powder, 8-12 parts of adhesive, 4-7 parts of plasticizer and 90-110 parts of alcohol.

4. The ceramic heating element according to any one of claims 1 to 3, characterized in that: The adhesive includes polyvinyl butyral; Preferably, the plasticizer comprises dibutyl phthalate; Preferably, the alcohol includes one or a combination of at least two of methanol, ethanol or ethylene glycol.

5. A method for preparing a ceramic heating body according to any one of claims 1 to 4, characterized in that: The preparation method comprises: Aluminum nitride powder, yttrium oxide powder, adhesive, plasticizer and alcohol are mixed and stirred, and then cast to obtain a green sheet; The obtained green sheets are used to prepare a first ceramic layer, a second ceramic layer and a third ceramic layer respectively; The first ceramic layer, the heating layer, the second ceramic layer, the radio frequency network layer and the third ceramic layer are assembled in sequence and then subjected to a hot pressing treatment, and then a first heat treatment and a second heat treatment are sequentially performed to obtain a ceramic heating body.

6. The preparation method according to claim 5, characterized in that: The thickness of the obtained green sheet is 0.3-0.6 mm; Preferably, the first ceramic layer is prepared by laminating 40-50 green sheets; Preferably, the second ceramic layer is prepared by laminating 30-40 green sheets; Preferably, the third ceramic layer is prepared by laminating 10-15 green sheets.

7. The preparation method according to claim 5 or 6, characterized in that: The temperature of the hot pressing treatment is 100-120°C; Preferably, the pressure of the hot pressing treatment is 50-80t; Preferably, the heat pressing treatment time is ≥ 1 h.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The temperature of the first heat treatment is 550-650°C; Preferably, the first heat treatment is performed under a protective atmosphere; Preferably, the first heat treatment is performed for 12-18 hours.

9. The preparation method according to any one of claims 5 to 8, characterized in that: The temperature of the second heat treatment is 1750-1850°C; Preferably, the second heat treatment is performed under a protective atmosphere; Preferably, the pressure of the second heat treatment is 18-25 MPa; Preferably, the second heat treatment time is 2-4 hours.

10. Use of a ceramic heating body according to any one of claims 1 to 4, characterized in that: The application includes preparing an aluminum nitride ceramic heater by using a ceramic heating body.

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