Ceramic structure

Abstract

This ceramic structure has a first layer having first crystal particles, a second layer positioned on the first layer and having second crystal particles, and an amorphous layer positioned between the first layer and the second layer. The first crystal particles and the second crystal particles each contain one or more metal elements that are selected from among Al, Si, Ti, Cr, Zr and Y, and one or more non-metallic elements that are selected from among N, C and B. The first crystal particles and the second crystal particles are composed of the same compound. The amorphous layer contains a metal element and a non-metal element.

Description

Ceramic Structure

[0001] SUMMARY OF THE INVENTION The disclosed embodiments relate to ceramic structures.

[0002] As described in Patent Document 1, a ceramic structure having a thin film formed on a substrate by chemical vapor deposition (CVD) is known. Patent Document 2 describes that a film formed by chemical vapor deposition is dense, void-free, and highly smooth. Patent Document 3 describes that the pore content is less than 3% by area.

[0003] JP-A No. 63-40314 JP-A No. 7-180057 JP-A No. 2020-53579

[0004] A ceramic structure according to one embodiment includes a first layer having first crystal particles, a second layer located on the first layer and having second crystal particles, and an amorphous layer located between the first and second layers. The first crystal particles and the second crystal particles each contain one or more metal elements selected from Al, Si, Ti, Cr, Zr, and Y, and one or more non-metal elements selected from N, C, and B. The first crystal particles and the second crystal particles are of the same compound. The amorphous layer contains the metal elements and the non-metal elements.

[0005] Fig. 1 is a cross-sectional view showing an example of a ceramic structure according to an embodiment. Fig. 2 is an enlarged view of region A shown in Fig. 1. Fig. 3 is a cross-sectional view showing another example of a ceramic structure according to an embodiment. Fig. 4 is a cross-sectional view showing another example of a ceramic structure according to an embodiment. Fig. 5 is a cross-sectional view showing another example of a ceramic structure according to an embodiment. Fig. 6 is an enlarged view of region B shown in Fig. 5. Fig. 7 is a cross-sectional view showing an example of a dendritic structure. Fig. 8 is a flowchart showing an example of a method for manufacturing a ceramic structure according to an embodiment.

[0006] The above-described structure leaves room for further improvement in terms of increasing the durability of the ceramic structure.

[0007] Therefore, there is a need for a ceramic structure with excellent durability.

[0008] Hereinafter, embodiments of the ceramic structure disclosed in the present application will be described with reference to the accompanying drawings. However, the present disclosure is not limited to the embodiments described below.

[0009] 1 is a cross-sectional view showing an example of a ceramic structure according to an embodiment. In the example shown in Fig. 1, the ceramic structure 1 has a first layer 10, a second layer 20, and an amorphous layer 30. The first layer 10 has first crystal particles 11. The second layer 20 has second crystal particles 21. The first crystal particles 11 and the second crystal particles 21 each contain one or more metal elements selected from Al, Si, Ti, Cr, Zr, and Y, and one or more non-metal elements selected from N, C, and B.

[0010] The first layer 10 may contain 50 area % or more of the first crystal grains 11. The first layer 10 may contain 80 area % or more of the first crystal grains 11. The first layer 10 may contain 90 area % or more of the first crystal grains 11.

[0011] The second layer 20 may contain 50 area % or more of the second crystal grains 21. The second layer 20 may contain 80 area % or more of the second crystal grains 21. The second layer 20 may contain 90 area % or more of the second crystal grains 21.

[0012] The amount of the second crystal grains 21 contained in the second layer 20 may be greater than the amount of the first crystal grains 11 contained in the first layer 10. The first crystal grains 11 and the second crystal grains 21 are the same compound. The first crystal grains 11 and the second crystal grains 21 are made of AlN, Si ３ N ４ , SiC, TiN, TiC, ZrN, ZrB, or YN. In particular, the first crystal particles 11 may be AlN. The meaning of being the same compound means that, for example, in the case of AlN, it is sufficient that Al and N are the main components and that it can be identified as AlN by XRD. For example, it is not necessary for the Al and N to be contained in a 1:1 ratio. The Al content may differ between the first crystal particles 11 and the second crystal particles 21.

[0013] The amorphous layer 30 is located between the first layer 10 and the second layer 20. The amorphous layer 30 contains the metal elements and non-metal elements contained in the first crystal grains 11 and the second crystal grains 21. With this configuration, stress generated between the first layer 10 and the second layer 20 is alleviated, and it is possible to provide a ceramic structure 1 with excellent durability.

[0014] The amorphous layer 30 may contain all of the metal elements and non-metal elements contained in the first crystal grains 11 and the second crystal grains 21. The amorphous layer 30 may not contain some of the metal elements and non-metal elements contained in the first crystal grains 11 and the second crystal grains 21. Furthermore, the amorphous layer 30 may contain elements different from the metal elements and non-metal elements contained in the first crystal grains 11 and the second crystal grains 21.

[0015] The amorphous layer 30 may be in contact with the surface 101 of the first layer 10 facing the second layer 20. The amorphous layer 30 may be in contact with the first surface 201 of the second layer 20 facing the first layer 10.

[0016] The thickness of the amorphous layer 30 may be, for example, less than 200 nm. The ceramic structure 1 may have a portion between the first layer 10 and the second layer 20 where the amorphous layer 30 is not located.

[0017] The thickness of the amorphous layer 30 can be measured by the following method. For example, it can be measured using a transmission electron microscope. For example, it can be measured using a JEM-ARM200F NEOARM transmission electron microscope (TEM) manufactured by JEOL Ltd. Since amorphous materials do not have a precise periodicity like crystals and have a random atomic arrangement, when an amorphous layer is present, no clear diffraction spots are observed, and instead a vague concentric halo pattern is observed.

[0018] The crystalline phase can be measured by the following method. Low-angle incidence measurements are performed using a thin-film X-ray diffractometer, X'Pert PRO-MRD (DY1878) manufactured by PANalytical. The optical system is configured with an X-ray mirror (automatic insertion attenuation plate, mask 5, Soller slit 0.02 rad, slit 1 / 8), a flat-plate collimator, a CuKα tube, X-rays at 45 kV and 40 mA, 2θ scan from 10° to 100°, an angle of incidence of 0.1°, a step of 0.02°, and a time of 4.0 seconds per step. For example, whether the crystalline particles are AlN may be determined based on JCPDS No. 00-025-1133.

[0019] 1, the first layer 10 is a substrate and may have, for example, a substantially disk shape. In the example shown in Fig. 1, the second layer 20 is located on the substrate (first layer 10), and the second layer 20 may be in contact with the substrate (first layer 10).

[0020] The substrate (first layer 10) contains, for example, a ceramic such as aluminum nitride (AlN) as a main component. The first layer 10 also contains, for example, aluminum oxide (Al ２ O ３ ), yttria (Y ２ O ３ ) or the like. The first layer 10 may also be a sintered body obtained by firing a raw material powder. When the first layer 10 is a sintered body, the first crystal grains 11 have a high degree of crystallinity. With such a configuration, a ceramic structure with excellent durability can be provided.

[0021] The first crystal particles 11 and the second crystal particles 21 may be hexagonal crystals. In the case of hexagonal crystals, the crystals have anisotropy, and by utilizing this anisotropy, it is possible to provide a ceramic structure with excellent durability.

[0022] The first crystal grains 11 and the second crystal grains 21 may also be made of AlN.

[0023] The second layer 20 may have voids 22 located therein. The voids 22 may be elongated in the thickness direction of the second layer 20, and both ends in the thickness direction may be closed. The voids 22 may have at least one of a first void 22a, one end of which in the thickness direction contacts the first layer 10, and a second void 22b, one end of which is spaced apart from the first layer 10. This configuration can reduce, for example, residual stress within the second layer 20. As a result, peeling or cracking between the first layer 10 and the second layer 20 is less likely to occur, and the durability of the ceramic structure 1 is improved.

[0024] The voids 22 may have a vertically elongated shape that is longer in the thickness direction than in the width direction of the second layer 20. The voids 22 may be closed at both ends in the thickness direction of the second layer 20. That is, the voids 22 are located between the first surface 201 of the second layer 20 facing the first layer 10 and the second surface 202 opposite the first surface 201, and may not be exposed at the second surface 202, which is the interface with the outside. Therefore, the second layer 20 has the desired durability even if it has voids 22 therein. The voids 22 are not lattice defects or so-called nanovoids that may exist in the second crystal particles 21. The width of the voids 22 may be, for example, 0.01 μm or more. The width of the voids 22 may be, for example, 0.05 μm or more. The width of the voids 22 may be, for example, 1 μm or less. The width of the voids 22 may be, for example, 0.5 μm or less. The length of the void 22 may be, for example, 0.2 μm or more. The length of the void 22 may be, for example, 0.5 μm or more. The length of the void 22 may be, for example, 5 μm or less. The length of the void 22 may be, for example, 1 μm or less.

[0025] The presence or absence of voids 22 can be confirmed, for example, by observation using an electron microscope. The area ratio of the voids 22 to the second layer 20 may be, for example, 3 area% or more. The area ratio of the voids 22 may be, for example, 4 area% or more. The area ratio of the voids 22 may be, for example, 5 area% or less. The area ratio of the voids 22 to the second layer 20 may be measured, for example, at the center of the cross section of the second layer 20 after mirror polishing. Observation using an electron microscope may be performed at a magnification of 1,000x to 50,000x. The electron microscope may be, for example, a JSM7900F manufactured by JEOL Ltd., and may be performed at an accelerating voltage of 5.0 kV. The area ratio of the voids 22 may be calculated based on an SEM photograph using image analysis software IMAGE Pro 10 manufactured by MEDIA CYBERNETICS, Inc. In this case, the SEM photograph may be binarized by the Ward method, and the calculation may be performed using the binarized image.

[0026] Furthermore, the void 22 may have a first void 22a and a second void 22b. The first void 22a is a void 22 whose lower end, which is one end in the thickness direction of the second layer 20, is in contact with the surface 101 of the first layer 10. The second void 22b is a void 22 whose one end is separated from the surface 101 of the first layer 10. The second layer 20 may have both the first void 22a and the second void 22b inside. The second layer 20 may have only one of the first void 22a and the second void 22b.

[0027] Next, the second layer 20 will be described in further detail with reference to Fig. 2. Fig. 2 is an enlarged view of region A shown in Fig. 1 .

[0028] The second crystal particles 21 included in the second layer 20 may have columnar crystals 21 a. The columnar crystals 21 a may extend, for example, in a direction intersecting the surface 101 of the first layer 10. That is, the columnar crystals 21 a may extend in the thickness direction of the second layer 20. The second layer 20 may have a plurality of columnar crystals 21 a aligned along the surface 101 of the first layer 10. When the second crystal particles 21 have columnar crystals 21 a, the thermal conductivity of the second layer 20 in the thickness direction is improved. Therefore, the temperature variation in the thickness direction of the second layer 20 is reduced, and the durability of the second layer 20 is improved.

[0029] Furthermore, the width of the voids 22, i.e., the length of the voids 22 in the direction along the surface 101 of the first layer 10, may be smaller at a second end 222 away from the first layer 10 than at a first end 221 in the thickness direction located on the first layer 10 side. This makes it difficult for the voids 22 to crack and spread from the second end 222 toward the second surface 202. This improves the durability of the ceramic structure 1 including the second layer 20. The voids 22 may be located between adjacent columnar crystals 21a. Such voids 22 may be larger or smaller than the columnar crystals 21a.

[0030] Furthermore, a space 40 may be present between the first layer 10 and the second layer 20. Here, the space 40 refers to a space extending along the surface 101 of the first layer 10. More specifically, in a cross-sectional view, the length of an imaginary line connecting both ends of the space 40 in a direction along the surface 101 is longer than the maximum height of the space 40 in a direction intersecting with the surface 101. More specifically, the length of an imaginary line connecting both ends of the space 40 in a direction along the surface 101 may be 5 times or more, and preferably 10 times or more, the height of the space 40 in a direction intersecting with the surface 101.

[0031] The second layer 20 may have a first portion closer to the first layer 10 with a larger porosity than a second portion farther from the first layer 10 than the first portion. This allows the thermal conductivity of the first portion to be smaller than that of the second portion. Therefore, when a thermal shock is applied to the ceramic structure 1 from the second layer 20 side, a sudden change in the temperature difference between the first layer 10 and the second layer 20 is suppressed. As a result, the durability of the ceramic structure 1 against thermal shock is improved. The first portion may be, for example, a region including the first surface 201 in the SEM image, and the second portion may be, for example, a region including the second surface 202 in the SEM image. The first and second portions may also partially overlap.

[0032] The amorphous layer 30 may be located so as to be in contact with both the first layer 10 and the second layer 20. The amorphous layer 30 may be spaced apart from one of the first layer 10 and the second layer 20.

[0033] 3 and 4 are cross-sectional views showing another example of a ceramic structure according to an embodiment. As shown in FIG. 3, the second layer 20 may have a plurality of columnar crystals 21a inclined with respect to the surface 101 of the first layer 10. Furthermore, voids 22 may be located between adjacent columnar crystals 21a. In this way, when the tips of the columnar crystals 21a contact the voids 22, the residual stress of the columnar crystals 21a is reduced, thereby improving the durability of the second layer 20. Note that, although first voids 22a are shown in FIG. 3 as an example of the voids 22, second voids 22b may also be used.

[0034] As shown in FIG. 4 , the first layer 10 may have an uneven surface 101 facing the second layer 20. Furthermore, the voids 22 may have a first end 221, which is one end in the thickness direction, located within the recess 101b of the first layer 10. This prevents the voids 22 from expanding in the direction along the surface 101 of the first layer 10 at the first end 221. As a result, cracks are suppressed in the columnar crystals 21a adjacent to the first end 221, improving the durability of the ceramic structure 1. The same applies when the voids 22 are located on the protrusions 101a of the first layer 10. While FIG. 4 illustrates the first voids 22a as an example of the voids 22, the second voids 22b may be used. Furthermore, the voids 22 may be located on the protrusions 101a of the first layer 10. In addition, although Figure 4 illustrates an example in which multiple columnar crystals 21a extend along the thickness direction of the second layer 20, they may extend at an angle relative to the thickness direction of the second layer 20 to correspond to the unevenness of the surface 101 of the first layer 10.

[0035] The volume resistivity of the second layer 20 at 25°C may be higher than the volume resistivity of the first layer 10 at 25°C. The volume resistivity of the second layer 20 at 500°C may be higher than the volume resistivity of the first layer 10 at 500°C. The volume resistivity of the second layer 20 at 25°C may be higher than 1×10 １２ The volume resistivity of the second layer 20 at 500°C may be 1×10 ５ It may be Ω·m or more.

[0036] The volume resistivity of the second layer 20 or the first layer 10 may be measured by a three-terminal method in accordance with JIS C 2141:1992.

[0037] The ceramic structure 1 may have a conductive layer therein. The conductive layer may have a heater function. The conductive layer may also have an adsorption function. The conductive layer may contain, for example, a metal such as W, Mo, Ni, or Pt.

[0038] Fig. 5 is a cross-sectional view showing another example of the ceramic structure according to the embodiment, and Fig. 6 is an enlarged view of region B shown in Fig. 5.

[0039] The second crystal particles 21 in the second layer 20 may have a dendritic structure 210. The dendritic structure 210 may have a stem 210a and branch portions 210b. In the stem 210a, the second crystal particles 21 are arranged, for example, in a direction intersecting the surface 101 of the first layer 10 (see FIG. 5 ). That is, in the stem 210a, the second crystal particles 21 are arranged in the thickness direction of the second layer 20. In the stem 210a, the second crystal particles 21 may be arranged in a direction perpendicular to the surface 101 of the first layer 10. The stem 210a may include a stem 210c in which the second crystal particles 21 are arranged so as to be tilted from the thickness direction of the first layer 10.

[0040] The second layer 20 may have a plurality of trunk portions 210a arranged along the surface 101 of the first layer 10. This configuration improves the thermal conductivity of the second layer 20 in the thickness direction. As a result, the second layer 20 reduces temperature variations in the thickness direction and improves durability.

[0041] The second layer 20 may have branch portions 210b in which the second crystal grains 21 are arranged in a direction having a crystal structure different from that of the stem portion 210a. Such a configuration can reduce, for example, residual stress within the second layer 20. This makes it less likely for delamination or cracks to occur between the first layer 10 and the second layer 20, improving the durability of the ceramic structure 1.

[0042] The second layer 20 may have a plurality of first regions 20a aligned along the surface 101 of the first layer 10 and second regions 20b located between adjacent first regions 20a. The trunk portion 210a may be located in the first region 20a. The plurality of first regions 20a and the branch portions 210b may be located in the second region 20b.

[0043] 7 is a cross-sectional view showing an example of a dendritic structure. The dendritic structure 210 has a stem 210a and a crystal structure different from that of the stem 210a. As shown in FIG. 7, the stem 210a has side surfaces 23 and 24 located at both ends in the width direction that intersects with the length direction.

[0044] The dendritic structure 210 may have branch-like portions 210b as a crystal structure different from the trunk-like portion 210a. The branch-like portions 210b may have a plurality of branch-like portions 210b1 located on the side surface 23 side of the trunk-like portion 210a. The branch-like portions 210b may have a plurality of branch-like portions 210b2 located on the side surface 24 side of the trunk-like portion 210a. The dendritic structure 210 may have branch-like portions 210b in which the second crystal particles 21 are arranged so as to form an angle θ of 30° or more and 60° or less with respect to the trunk-like portion 210a.

[0045] The trunk portion 210a may be positioned so as to contact a first surface 201 (see FIG. 5 ) of the second layer 20 facing the first layer 10. The trunk portion 210a may be positioned so as to contact a second surface 202 (see FIG. 5 ) opposite the first surface 201. Alternatively, the trunk portion 210a may be positioned away from the first surface 201 and the second surface 202.

[0046] The branch portion 210b may be in contact with the trunk portion 210a, or may be spaced apart from the trunk portion 210a.

[0047] 7, the dendrite structure 210 may have voids 25 where the trunk portions 210a and the branch portions 210b are not located. Such a configuration further reduces, for example, residual stress inside the second layer 20. This reduces the likelihood of peeling or cracks occurring between the first layer 10 and the second layer 20, improving the durability of the ceramic structure 1.

[0048] The second layer 20 of the ceramic structure 1 may have, as the second crystal grains 21, one or both of columnar crystals 21a and dendritic structures 210.

[0049] <Method for Manufacturing Ceramic Structure> An example of a method for manufacturing a ceramic structure will be described with reference to Fig. 8. Fig. 8 is a flowchart showing an example of a method for manufacturing a ceramic structure according to an embodiment.

[0050] A disk-shaped sintered body containing 90% to 99.9% by mass of AlN is prepared as the substrate (first layer 10). Then, a second layer containing AlN as a main component is formed on the surface of this substrate by the following procedure. First, a catalyst is applied to a first gas (step S11). The first gas may contain nitrogen, and ammonia, for example, can be used. Tungsten, for example, can be used as the catalyst. For example, when the catalyst is applied to the first gas in an environment of approximately 1600°C to 2200°C, the first gas is decomposed by the catalytic action, generating multiple active species.

[0051] Next, the activated species generated in step S11 and a second gas are supplied to the first layer 10 (step S12). As the second gas, for example, trimethylaluminum can be used.

[0052] Next, the second layer 20 is formed on the first layer 10 (step S13). The first layer 10 may be heated as needed. The temperature of the first layer 10 may be set to, for example, 420°C to 1000°C, particularly a temperature greater than 700°C and equal to or less than 1000°C. The deposition time may be, for example, 0.5 hours to 20 hours depending on the desired thickness. The deposition pressure (deposition pressure) may be set to 10 Pa to 100 Pa. The deposition pressure may be set to, particularly, 20 Pa or less, or even 10 Pa. For example, a ceramic structure 1 may be obtained in which the second layer 20 having a different crystal structure is formed on the first layer 10 depending on the temperature set during deposition (deposition temperature), and an amorphous layer 30 is located between the second layer 20 and the first layer 10.

[0053] An AlN sintered body containing 98% by mass of AlN crystals as the main phase was prepared. This AlN sintered body was processed into a first layer measuring 100 mm square. A conductive layer containing W as the metal was disposed inside the AlN sintered body. This conductive layer was formed into a heater pattern. Next, a second layer was formed on one surface of the first layer using ammonia as the first gas, trimethylaluminum as the second gas, and tungsten as the catalyst. The deposition temperature and deposition pressure in step S13 are shown in Table 1. The presence or absence of an amorphous layer between the first and second layers of the resulting ceramic structure, as well as the thickness of the amorphous layer, are also shown in Table 1. As a comparative example, the aforementioned AlN sintered body without a second layer was used. Sample No. 8 is another comparative example in which a film was formed without using a catalyst.

[0054] Furthermore, the presence or absence of voids, the shape of the voids, etc. were observed using a cross section of the second layer of the obtained ceramic structure. As a comparative example, a case where the portions corresponding to the first and second layers were made of a sintered body is also shown in Table 1. Table 1 shows the film formation temperature and the above measured values. In Table 1, blanks and "-" indicate that measurements were not made or that calculations were not made.

[0055]

[0056] Sample No. 1 had no interface. Sample No. 8 had an interface but no amorphous layer. Sample No. 8, which had no amorphous layer, had a low deposition rate and poor productivity. On the other hand, amorphous layers were observed in Samples No. 2 to No. 7. Amorphous layers with thicknesses of 50 nm to 200 nm were observed in Samples No. 5 to No. 7. Samples No. 6 and No. 7, which had amorphous layers with thicknesses of 50 nm to 200 nm, exhibited particularly excellent durability. Note that Sample No. 7, which had an amorphous layer with a thickness of 50 nm, exhibited the best adhesion strength. The durability of the ceramic structure was evaluated by measuring the adhesion strength between the first and second layers, and samples with excellent adhesion strength were judged to have excellent durability. The results in Table 1 indicate that the thinner the amorphous layer, the greater the adhesion strength, as long as the thickness is less than 200 nm.

[0057] The adhesion strength was calculated based on the value measured using an Autograph AG-IS manufactured by Shimadzu Corporation. First, a Φ20 mm flat screw jig was attached with an adhesive to the surface of the second layer of a plate-shaped sample (20 mm x 40 mm) having a second layer, and the flat screw jig was lifted approximately perpendicular to the surface of the plate-shaped sample to measure the maximum force at which the adhesive portion broke. The value obtained by dividing this maximum force by the area of ​​the adhesive portion was taken as the adhesion strength.

[0058] In one embodiment, (1) a ceramic structure includes: a first layer having first crystal particles; a second layer located on the first layer and having second crystal particles; and an amorphous layer located between the first layer and the second layer, wherein the first crystal particles and the second crystal particles each contain one or more metal elements selected from Al, Si, Ti, Cr, Zr, and Y, and one or more non-metal elements selected from N, C, and B, the first crystal particles and the second crystal particles are the same compound, and the amorphous layer contains the metal elements and the non-metal elements.

[0059] (2) In the ceramic structure of (1) above, the amorphous layer may have a thickness of less than 200 nm.

[0060] (3) In the ceramic structure of (1) or (2) above, the second layer may have a void located inside the second layer, the void being long in the thickness direction of the second layer and having both ends in the thickness direction closed, and the void may include at least one of a first void having one end in the thickness direction in contact with the first layer and a second void having one end away from the first layer.

[0061] (4) In the ceramic structure of (3) above, the second layer may have a porosity of 3 area % or more and 5 area % or less in a cross section parallel to the thickness direction.

[0062] (5) In the ceramic structure of (3) or (4), the second layer may have a plurality of columnar crystals inclined with respect to a surface of the first layer, and the voids may be located between adjacent ones of the plurality of columnar crystals.

[0063] (6) In the ceramic structure of any one of (3) to (5) above, the first layer may have an uneven surface facing the second layer, and one end of the void in the thickness direction may be located within a recess in the first layer.

[0064] (7) In any one of the ceramic structures (3) to (6) above, the length of the void in a direction along the surface of the first layer may be smaller at a second end away from the first layer than at a first end in the thickness direction located on the first layer side.

[0065] (8) In the ceramic structure of any one of (3) to (7) above, the second layer may have a first portion closer to the first layer that has a larger porosity than a second portion that is farther from the first layer than the first portion.

[0066] (9) The ceramic structure according to any one of (1) to (8) above may have an internal conductive layer.

[0067] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the disclosure in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0068] REFERENCE SIGNS LIST 1 ceramic structure 10 first layer 11 first crystal particle 20 second layer 21 second crystal particle 21a columnar crystal 22 void 22a first void 22b second void 30 amorphous layer 40 space 101 surface 101a convex portion 101b concave portion 201 first surface 202 second surface 210 dendritic structure 210a stem portion 210b branch portion 221 first end portion 222 second end portion

Claims

1. A ceramic structure comprising: a first layer having first crystal particles; a second layer located on the first layer and having second crystal particles; and an amorphous layer located between the first layer and the second layer, wherein the first crystal particles and the second crystal particles each contain one or more metal elements selected from Al, Si, Ti, Cr, Zr, and Y, and one or more non-metal elements selected from N, C, and B, the first crystal particles and the second crystal particles are of the same compound, and the amorphous layer contains the metal elements and the non-metal elements.

2. The ceramic structure of claim 1, wherein the amorphous layer has a thickness of less than 200 nm.

3. The ceramic structure according to claim 1 or 2, wherein the second layer has a void located therein, the void being long in the thickness direction of the second layer and closed at both ends in the thickness direction, and the void comprises at least one of a first void having one end in the thickness direction in contact with the first layer and a second void having one end remote from the first layer.

4. The ceramic structure according to claim 3, wherein the second layer has a porosity of 3 area % or more and 5 area % or less in a cross section parallel to the thickness direction.

5. The ceramic structure according to claim 3 or 4, wherein the second layer has a plurality of columnar crystals inclined with respect to the surface of the first layer, and the voids are located between adjacent ones of the plurality of columnar crystals.

6. A ceramic structure according to any one of claims 3 to 5, wherein the first layer has an uneven surface facing the second layer, and one end of the void in the thickness direction is located within a recess in the first layer.

7. A ceramic structure according to any one of claims 3 to 6, wherein the length of the void in the direction along the surface of the first layer is smaller at a second end remote from the first layer than at a first end in the thickness direction located on the first layer side.

8. A ceramic structure according to any one of claims 3 to 7, wherein the second layer has a first portion closer to the first layer that has a larger porosity than a second portion that is farther from the first layer than the first portion.

9. The ceramic structure according to any one of claims 1 to 8, having an internal conductive layer.

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