KR20160136213A

KR20160136213A - Silicon Based Ceramic with Crystalline Zircon Coating and Method for Manufacturing the Same

Info

Publication number: KR20160136213A
Application number: KR1020160004243A
Authority: KR
Inventors: 박동수; 한병동; 이건환; 류정호; 최종진
Original assignee: 한국기계연구원
Priority date: 2015-05-18
Filing date: 2016-01-13
Publication date: 2016-11-29
Also published as: KR101835840B1

Abstract

The present invention relates to a silicon-based ceramic coated with crystalline zirconium, and a process for producing the same. According to the present invention, a silicon oxide layer is formed on the surface of a silicon-containing substrate, or an appropriate surface roughness is imparted to the surface of the silicon-containing substrate and then the zircon is coated to obtain a silicon-based ceramic exhibiting excellent corrosion resistance including high temperature characteristics and oxidation resistance Can be easily manufactured, and can be usefully used in products such as aviation parts.

Description

TECHNICAL FIELD [0001] The present invention relates to a silicon-based ceramic coated with a crystalline zircon and a method for manufacturing the same,

The present invention relates to a silicon-based ceramic coated with crystalline zirconium, and a process for producing the same. More specifically, the present invention relates to a method for manufacturing a silicon-containing substrate, which comprises forming a silicon oxide layer on the surface of a silicon-containing substrate, or applying a surface roughness to the surface of the silicon- Coated silicon-based ceramics, and a method of manufacturing the same.

Ceramics is a core material used in a variety of fields from the aerospace industry to smart phones and other advanced electronic communication devices. Ceramic materials can withstand high temperatures and corrosive environments, but must be sintered or coated to minimize the fragile nature of the ceramic.

Silicon carbide or silicon nitride ceramics have excellent mechanical properties such as high temperature characteristics and thermal shock resistance and are used in applications such as machines and aviation parts that can be applied at high temperatures. However, like other non-oxide ceramics At higher temperatures, corrosion, including oxidation, proceeds.

In particular, silicon carbide is being used or developed for various high-temperature materials in the form of monoliths, composites and coatings.

The oxide ceramic coating is one of the measures to suppress the high temperature oxidation of silicon carbide. However, the thermal expansion coefficient (4 ppm / K) of silicon carbide is lower than the thermal expansion coefficient of general oxide ceramics, have.

On the other hand, zircon (ZrSiO ₄ ) has a thermal expansion coefficient similar to that of silicon carbide or silicon nitride (thermal expansion coefficient: 3.3 ppm / K) in oxide ceramics and is chemically stable. Therefore, oxidation resistance of silicon carbide or silicon nitride is improved Suitable for coatings.

Conventional zircon coatings can be applied directly to the silicon carbide surface by solution techniques such as chemical vapor deposition (CVD), thermal spraying such as plasma spraying, sol-gel, slurry coating, or colloidal suspension coating . However, the zircon produced by thermal spraying is exposed to high temperatures during the coating process, and a significant amount is melted and then coated on the substrate. Therefore, when the melted zircon is solidified, it is decomposed into ZrO ₂ and SiO ₂ , and thus the actual zircon and other materials are coated.

As a background of the present invention, there is disclosed a ceramic coated with zircon in U.S. Patent No. 6,517,960 (February 11, 2003).

United States Patent No. 6,517,960 (Feb.

An object of the present invention is to provide a silicon-based ceramic coated with a crystalline zircon having excellent corrosion resistance including high temperature characteristics and oxidation resistance.

Another object of the present invention is to provide a method for easily producing a silicon-based ceramic coated with a crystalline zircon coating excellent in corrosion resistance including oxidation resistance since the zircon coating layer is not decomposed due to the need for high temperature treatment.

Other objects and advantages of the present invention will become more apparent from the following detailed description of the invention, claims and drawings.

It is an object of the present invention to provide a silicon oxide substrate having a low hardness and a similar thermal expansion coefficient on the surface of a silicon-containing substrate so as not to cause peeling of the coating layer and to form an excellent thermal barrier film, Coating the surface with an appropriate surface roughness, and then coating the zircon to obtain a silicon-based ceramic coated with a crystalline zircon.

Thus, in accordance with one aspect of the present invention, the present invention provides a substrate having a silicon-based ceramic surface; And a zircon coating layer coated on the surface of the substrate with crystalline zircon. The present invention also provides a silicon-based ceramic coated with a crystalline zircon.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: a substrate having a silicon-based ceramic surface; A zircon coating layer coated on the surface of the substrate with crystalline zircon; And a silicon oxide layer formed between the base material and the zircon coating layer. The present invention also provides a silicon-based ceramic coated with a crystalline zircon.

According to another aspect of the present invention, there is provided a ceramic article comprising the ceramic.

According to another aspect of the present invention, there is provided a method of manufacturing a silicon-based ceramic substrate, comprising: forming a silicon oxide layer on a silicon-based ceramic substrate surface; And coating a crystalline zircon on the silicon oxide layer. The present invention also provides a method for producing a silicon-based ceramic coated with a crystalline zircon.

According to another aspect of the present invention, there is provided a method of manufacturing a silicon-based ceramic substrate, the method including: applying a surface roughness to a silicon- And coating crystalline zircon on the surface of the substrate. The present invention also provides a method for producing a silicon-based ceramic coated with a crystalline zircon.

According to an embodiment of the present invention, the silicon-based ceramics coated with the crystalline zircon according to the present invention have an advantage of having excellent corrosion resistance including high-temperature characteristics and oxidation resistance, and forming an interface layer having strong bonding force.

According to one embodiment of the present invention, the zircon-coated silicon-based ceramic manufacturing method of the present invention does not require the formation of zircon or the heating process for densifying the coating layer, and the zircon coating layer is not decomposed, A ceramic coated with a crystalline zircon excellent in corrosion resistance and the like can be easily produced.

The silicon-based ceramics produced by the present invention can be usefully used as a material for various ceramic products such as aviation parts which require excellent corrosion resistance including high temperature characteristics and oxidation resistance.

1 is a conceptual view schematically showing a vacuum granule injection device at room temperature.
Fig. 2 is a granular photograph put into a vacuum granule injection device at room temperature.
FIG. 3 is a photograph showing a comparative example in which zircon is coated without forming the silicon oxide interface layer of the present invention, and silicon carbide coated with zircon after forming a silicon oxide interface layer according to an embodiment. (Comparative Example 1 in which the coating layer was not formed and the coating layer was not formed). After polishing, the coating was oxidized in air at 1200C-10h to form a silicon oxide interface layer, and then coated with zircon (Example 1), right) and after polishing, 1200C-100h in air to form a silicon oxide interface layer and then coated with zircon (Example 2).
4 is a scanning electron microscope (SEM) photograph and a projection electron microscope (TEM) photograph of a cross-section of a silicon carbide-based ceramic coated with crystalline zircon according to the first embodiment of the present invention with a focused ion beam (FIB).
5 is a scanning electron microscope (SEM) photograph and a projection electron microscope (TEM) photograph of a cross-section of a silicon carbide-based ceramic coated with crystalline zircon according to the second embodiment of the present invention with a focused ion beam (FIB).
6 is a scanning electron microscope (SEM) photograph and a projection electron microscope (TEM) photograph of a cross-section of a silicon carbide-based ceramic coated with crystalline zircon according to the third embodiment of the present invention with a focused ion beam (FIB).
7 is a scanning electron microscope (SEM) photograph and a projection electron microscope (TEM) photograph of a cross-section of a silicon carbide-based ceramic coated with crystalline zircon according to the fourth embodiment of the present invention with a focused ion beam (FIB).
FIG. 8 is a scanning electron microscope (SEM) photograph and a projection electron microscope (TEM) photograph of a cross section of a silicon carbide-based ceramic coated with crystalline zircon according to the fifth embodiment of the present invention with a focused ion beam (FIB).
9 is a graph showing an XRD pattern of a silicon carbide-based ceramic coated with crystalline zircon according to a fourth embodiment of the present invention.
10 is a photograph showing the formation of a coating layer of a silicon carbide-based ceramic coated with crystalline zircon according to the sixth and seventh embodiments of the present invention in comparison with comparative examples.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and particular embodiments are illustrated in the drawings and will be described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprises", "having", and the like are intended to specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a silicon-based ceramic coated with a crystalline zircon according to an embodiment of the present invention and a method of manufacturing the same will be described in detail with reference to the accompanying drawings. The same reference numerals will be assigned to the constituent elements, and redundant explanations thereof will be omitted.

For the sake of convenience of explanation, the direction of each constitution is based on the direction shown in the figure. However, the description based on such a direction is merely an example of the operating state, and is not intended to limit the crystalline zircon-coated silicon-based ceramics according to this embodiment, and the manufacturing method thereof.

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: a substrate having a silicon-based ceramic surface; And a zircon coating layer coated on the surface of the substrate with crystalline zircon. The present invention also provides a silicon-based ceramic coated with a crystalline zircon.

In the present invention, the substrate is not particularly limited as long as it has a silicon-based ceramic surface. But is not limited to, silicon-based carbide such as silicon carbide (SiC), or silicon-based nitride such as silicon nitride (Si ₃ N ₄ ). The substrate may be a single substance or a composite. For example, the present invention may be applied to SiC precoated on a carbon / carbon (C / C) composite surface.

According to an embodiment of the present invention, the zircon-coated silicon-based ceramic according to the present invention includes an interfacial layer of silicon oxide formed between the substrate and the zircon coating layer. When the zircon is directly sprayed on the surface of the high hardness silicon carbide, peeling of the coating layer occurs and it is difficult to form a healthy coating layer. That is, the ceramic coating layer formed by vacuum granule spraying at room temperature is anchored to the surface of the base material by the ceramic particles injected from the interface with the base material, thereby providing a bonding force between the coating layer and the base material, and anchoring of zircon is difficult to occur sufficiently in the base material having high hardness. Therefore, in the present invention, a silicon oxide layer having a thermal expansion coefficient similar to that of a base material containing silicon but having a lower hardness is formed, and zircon is sprayed on the silicon oxide layer to form an interface layer having strong bonding force.

According to an embodiment of the present invention, the thickness of the silicon oxide layer is 1 to 1000 nm. Although not limited thereto, if the thickness of the silicon oxide layer is less than 1 nm or exceeds 1000 nm, it may be difficult to provide a sufficient bonding force between the substrate and the zircon coating layer.

The silicon oxide layer does not necessarily have to be uniformly formed but may be partially formed as long as it can provide sufficient bonding force between the substrate and the zircon coating layer.

According to an embodiment of the present invention, the thickness of the zircon coating layer is 2 - 20 μm, preferably 2 - 15 μm, more preferably 2 - 10 μm. If the thickness of the zircon coating layer is less than 2 μm, it may not help to improve the high-temperature characteristics and oxidation resistance of the silicon-based ceramic. If the thickness is more than 20 μm, the effect of improving the high- .

According to one embodiment of the present invention, the average particle size in the crystalline zircon coating layer is 1 μm or less. Forming the crystalline zircon having an average particle size of 1 μm or less may improve the high-temperature characteristics and oxidation resistance of the silicon-based ceramic by improving the density of the coating layer.

According to an embodiment of the present invention, the content of crystalline zircon in the solid content in the zircon coating layer is 70% or more. The solid content means a solid portion excluding pores. The zircon coating layer of the silicon-based ceramic according to the present invention is not limited to this, but it is preferable that the zircon coating layer has a crystalline zircon content of 70% or more, preferably 80% or more, more preferably 90% or more, Is 95% or more. As described above, the zircon coating layer according to the present invention is composed of crystalline zirconia (ZrSiO ₄ ) instead of zirconia (ZrO ₂ ) in the form of oxide and has a thermal expansion coefficient similar to that of the silicon-based ceramic, thereby exhibiting excellent corrosion- .

The crystalline zircon coating layer may be formed by a room temperature vacuum granulation process. The crystalline zircon coating layer contains no organic matter. This is because they were formed using granules from which organics were removed.

According to an embodiment of the present invention, the porosity of the zircon coating layer is 10% or less. Although not limited thereto, if the porosity of the zircon coating layer exceeds 10%, the effect of improving the high-temperature characteristics and oxidation resistance of the silicon-based ceramic may not be large.

In the silicon-based ceramics coated with the crystalline zircon of the present invention, if an appropriate surface roughness is imparted to the surface of the silicon-based ceramic through sandblasting, mechanical processing, or the like, the contact between the substrate having the silicon-based ceramic surface and the zircon- The peeling of the zircon coating layer can be suppressed regardless of the presence or absence of the artificial silicon oxide interface layer by widening the area or providing an artificial anchoring point.

According to one embodiment of the present invention, the surface of the silicon-based ceramic surface has a roughness in the range of 0.3 to 2.3 μm, preferably in the range of 0.3 to 1.7 μm, more preferably in the range of 0.3 to 1.5 μm. If the surface roughness of the surface of the zircon coating layer is less than 0.3 μm, the zircon coating layer may easily peel off and the effect of improving the corrosion resistance including the high-temperature characteristics and the oxidation resistance of the silicon-based ceramic may be insufficient. It is difficult to form a good quality zircon coating layer.

According to another aspect of the present invention, there is provided a ceramic article comprising the ceramic. The ceramic product is not particularly limited as long as high-temperature characteristics and oxidation resistance are required. Although not limited thereto, the ceramic according to the present invention can be applied to various products such as parts applicable to high-temperature machines, aerospace industrial components, and parts for manufacturing parts for advanced electronic communication devices such as smart phones.

The silicon oxide layer can be formed on the surface of the silicon-based ceramic substrate by various techniques known in the art. For example, the surface of the silicon-based ceramic base can be oxidized at a high temperature to form a silicon oxide layer having a certain thickness.

According to one embodiment of the present invention, the surface of the silicon-based ceramic substrate such as silicon carbide may be coated with zircon after an appropriate surface roughness is imparted through sandblasting, mechanical processing, or the like. The sand blasting process can suppress the peeling of the zircon coating layer regardless of the presence of the artificial silicon oxide interface layer by widening the contact area between the silicon-containing substrate and the zircon coating layer or providing an artificial anchoring point, .

According to one embodiment of the present invention, the step of coating the crystalline zircon is performed by a room-temperature vacuum granule spraying method. In the present invention, the zircon coating layer may be formed by various known methods. Although not limited thereto, the zircon coating layer is formed by coating a crystalline zircon on the silicon oxide layer by, for example, a room temperature vacuum granulation process. When zircon is coated by conventional plasma spray thermal spraying, zircon (ZrSiO ₄ ) is exposed to high temperature in the coating process and decomposed into ZrO ₂ and SiO ₂ instead of zircon, so that a zircon coating layer is not formed substantially . When the zircon is coated by the vacuum granule injection at room temperature according to the present invention, the high temperature treatment is not required and the problems of the prior art can be solved and the crystalline zircon coating layer can be efficiently formed.

The vacuum granule injection process at room temperature means a coating process using granules having a size of 5 to 500 mu m mixed with a transfer gas. While the aerosol means mixed state of ultrafine particles and gas, it is difficult to name granules of 5 - 500 μm size mixed with gas as aerosol, The coating process using granules is defined as a room temperature vacuum granule injection process, and more particularly, it is referred to Korean Patent No. 10-1380836.

According to an embodiment of the present invention, the thickness of the zircon coating layer is 2 to 20 μm, preferably 2 to 15 μm, more preferably 2 to 10 μm. If the thickness of the zircon coating layer is less than 2 μm, it may not help to improve the high-temperature characteristics and oxidation resistance of the silicon-based ceramic. If the thickness is more than 20 μm, the effect of improving the high- .

According to one embodiment of the present invention, the average particle size in the crystalline zircon coating layer is formed to be 1 μm or less. Forming the crystalline zircon coating layer with an average particle size of 1 μm or less may improve the high-temperature characteristics and oxidation resistance of the silicon-based ceramic by improving the density of the coating layer.

According to an embodiment of the present invention, the surface of the silicon-based ceramic surface has a roughness in the range of 0.3 μm to 2.3 μm, preferably in the range of 0.3 to 1.7 μm, and more preferably in the range of 0.3 to 1.5 μm . If the roughness of the surface of the zircon coating layer is less than 0.3 μm, the zircon coating layer may easily peel off and the effect of improving the high-temperature characteristics and oxidation resistance of the silicon-based ceramic may not be sufficient. If the surface roughness is more than 2.3 μm, .

As described above, according to the present invention, a silicon oxide layer having a hardness lower than that of the base material is formed on the surface of a silicon-containing base material, or a silicon nitride base material surface is coated with zirconium at a room temperature vacuum granule- , And corrosion resistance including oxidation resistance can be easily manufactured by using a ceramic zircon-coated ceramic composite. Therefore, the zircon-coated ceramic according to the present invention can be usefully used as a material for machines and aviation parts applicable at high temperatures.

Silicon oxide layer formation

A commercial silicon carbide sintered body is placed on an alumina plate and placed in a high-temperature electric furnace, and then heated to an oxidation temperature in air at a heating rate of 5 ° C per minute. The oxidation temperature can be appropriately selected in the range of 800 占 폚 to 1200 占 폚. The silicon oxide layer can be formed on the surface of the silicon carbide sintered body by holding the silicon oxynitride layer at a selected oxidation temperature for a suitable time within a range of 30 minutes to 100 hours depending on the silicon carbide composition and the thickness of the silicon oxide layer to be formed. After the oxidation temperature was maintained for a predetermined time, the silicon carbide with the oxide layer was taken out of the electric furnace and used as a substrate for zircon coating.

Surface roughness

The ground silicon carbide can have an appropriate surface roughness, but the abrasive silicon carbide can be subjected to sandblasting to give an appropriate surface roughness. The surface roughness of the abrasive or abrasive silicon carbide surface was controlled by sandblasting the 100-grit white alumina powder at 5 atm.

Zircon coating

FIG. 1 is a conceptual view schematically showing a vacuum granule injection device at room temperature, and FIG. 2 is a granular photograph of the vacuum granule injection device at room temperature.

The average particle size (d50) of the zirconium raw material powder used was -600 mesh. The average particle size (d50) was 2.7 μm. The raw material powder was mixed with a binder and a dispersant to prepare a slurry using water as a medium, followed by spray drying to form granules.

The prepared granules were heat-treated at 600 ° C. for 4 hours to remove the organic binder and dispersant added to the granules. The granules from which the organics were removed were put into a vacuum granule injection apparatus at room temperature in FIG. 1, and the granules were sprayed onto the substrate through a nozzle to form a coating layer.

At this time, a nozzle having a slit-shaped outlet was used, and a nozzle having a slit width of 30 mm or a nozzle having a diameter of 400 mm was used. The injected granules were sprayed onto the surface of SiC substrate by vacuum granule injection process at room temperature. The transport gas used for the transfer and injection of granules was medical grade purified dry compressed air. The transport gas is not limited and various gases may be used, but the compressed air is judged to be the most economical.

The porosity was obtained by Image analysis method using ImagePro 7.0 software in cross-sectional TEM photographs.

Comparative Example One, Example 1 to 5

The specimens of Comparative Example 1 and Examples 1 and 2 were disk-shaped with a diameter of 80 mm and their surfaces were polished. The coating was tested simultaneously using 400 mm wide nozzles with the three specimens transversely. The specimens of Examples 3 to 5 are plates having hexagonal faces of 17 mm on one side and the surfaces are ground. The coating was tested using a 30 mm wide nozzle.

The conditions of the specific examples and comparative examples and the results thereof are shown in Table 1 and Figs. 3 to 8. 9 is a graph showing an XRD pattern of a silicon carbide-based ceramic coated with crystalline zircon according to a fourth embodiment of the present invention.

Comparative Examples 1 to 3, Examples 6 and 7

The specimens of Comparative Examples 2 and 3 had a hexagonal grinding surface of 17 mm on one side and were polished to control the surface roughness. The specimen of Example 6 and the specimen of Example 7 were sandblasted To form a zircon coating layer after roughing the surface. The coating was tested using a 30 mm wide nozzle.

The conditions and the results of specific examples and comparative examples are shown in Table 2 and FIG.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit of the invention as defined in the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

A substrate having a silicon-based ceramic surface; And
And a zircon coating layer coated on the surface of the substrate with crystalline zircon.

A substrate having a silicon-based ceramic surface;
A zircon coating layer coated on the surface of the substrate with crystalline zircon; And
And a silicon oxide layer formed between the substrate and the zircon coating layer.

3. The method of claim 2,
Wherein the silicon oxide layer has a thickness of 1 - 1000 nm.

3. The method according to claim 1 or 2,
Wherein the zircon coating layer has a thickness of 2 - 20 탆.

5. The method of claim 4,
Wherein the zircon coating layer has a thickness of 2-15 mu m.

5. The method of claim 4,
Wherein the zircon coating layer has a thickness of 2 - 10 탆.

3. The method according to claim 1 or 2,
Wherein the crystalline zircon has an average particle size of 1 um or less.

3. The method according to claim 1 or 2,
Wherein a content of crystalline zircon in the solid content in the zircon coating layer is 70% or more.

9. The method of claim 8,
Wherein the crystalline content of the solid content in the zircon coating layer is 80% or more.

9. The method of claim 8,
Wherein a content of crystalline zircon in the solid content in the zircon coating layer is 90% or more.

9. The method of claim 8,
Wherein the content of crystalline zircon in the solid content in the zircon coating layer is 95% or more.

3. The method according to claim 1 or 2,
Wherein the zircon coating layer is a zircon-coated silicon-based ceramic material containing no organic substance.

3. The method according to claim 1 or 2,
Wherein the silicon-based ceramic has a surface roughness of 0.3 to 2.3 탆.

14. The method of claim 13,
Wherein the silicon-based ceramic has a surface roughness of 0.3 to 1.7 um.

14. The method of claim 13,
Wherein the silicon-based ceramic has a surface roughness of 0.3 - 1.5 탆 and a crystalline zircon-coated silicon-based ceramic.

A ceramic product comprising the ceramic according to any one of claims 1 to 3.

Forming a silicon oxide layer on the silicon-based ceramic substrate surface; And
And coating the crystalline silicon oxide layer with a crystalline zircon.

Applying a surface roughness to the surface of the silicon-based ceramic base; And
And coating the crystalline zircon on the surface of the substrate.

The method according to claim 17 or 18,
Wherein the step of coating the crystalline zircon is performed by a room-temperature vacuum granular spraying method.

20. The method of claim 19,
The method of manufacturing the silicon-based ceramic coated with the crystalline zircon is a method of spraying granules having a size of 5 to 500 mu m mixed with a transfer gas.

The method according to claim 17 or 18,
Wherein the zircon coating layer has a thickness of 2 - 20 탆.

22. The method of claim 21,
Wherein the zircon coating layer has a thickness of 2 - 15 탆.

22. The method of claim 21,
Wherein the zircon coating layer has a thickness of 2 - 10 탆.

The method according to claim 17 or 18,
Wherein the average particle size of the crystalline zircon coating layer is less than 1 um.

The method according to claim 17 or 18,
Wherein the crystalline zircon content of the solid content in the zircon coating layer is 70% or more.

26. The method of claim 25,
Wherein the crystalline zircon content of the solid content in the zircon coating layer is 80% or more.

26. The method of claim 25,
Wherein the crystalline zircon content of the solid content in the zircon coating layer is 90% or more.

26. The method of claim 25,
Wherein a crystalline zircon content of the solid content in the zircon coating layer is 95% or more.

The method according to claim 17 or 18,
Wherein the zircon coating layer has a porosity of 10% or less.

18. The method of claim 17,
Wherein the silicon oxide layer has a thickness of 1 to 1000 nm.

The method according to claim 17 or 18,
Wherein the silicon-based ceramic surface has a surface roughness of 0.3 to 2.3 μm.

32. The method of claim 31,
Wherein the silicon-based ceramic has a surface roughness of 0.3 to 1.7 um.

32. The method of claim 31,
Wherein the silicon-based ceramic has a surface roughness of 0.3 to 1.5 um.