RBSiC parts with SiC coating, use of SiC coating, and manufacturing method of parts

Abstract

The present invention relates to a component (1) comprising a component body (2) made of reaction-bonded silicon carbide (RBSiC), wherein the component body (2) has a body surface (3) that is at least partially covered with a coating (4), and the coating (4) is made of silicon carbide (SiC) having a layer thickness of at least 25 μm. The present invention also relates to the use of such SiC coatings and to a method for manufacturing a component comprising a SiC coating.

Description

Technical Field

[0001] The present invention relates to a component having a component body made of reaction-bonded silicon carbide (RBSiC) according to the preamble of claim 1, a use according to claim 23, and a method for manufacturing a component having a component body made of reaction-bonded silicon carbide (RBSiC) according to claim 24.

Background Art

[0002] Various components made of reaction-bonded silicon carbide (RBSiC) are conventionally known. RBSiC has excellent temperature stability up to 1380°C, a low coefficient of thermal expansion, high rigidity (elastic modulus > 380 GPa), and high hardness. Therefore, products based on RBSiC are employed in numerous heavy industrial fields including burners and radiant tubes of industrial furnaces, rollers for roller furnaces, firing aids for sintering of porcelain and cordierite, and slide ring packings. A further advantage of RBSiC is its low shrinkage rate (less than 1%) in the manufacturing process, which enables the production of very large components with high dimensional accuracy.

[0003] However, there are also many applications where the current properties of RBSiC are insufficient. In such applications, components made of sintered silicon carbide (SSiC) have conventionally been manufactured. SSiC has higher hardness, better strength, better chemical resistance, and higher temperature stability compared to RBSiC. The drawback is that the shrinkage rate in the manufacturing process is significantly larger than that of RBSiC, which makes the production of components from SSiC more complicated. The SSiC material shrinks by more than 10%, typically about 20%, in the sintering process. This causes problems such as cracking, component stress, and insufficient dimensional accuracy, especially in the production of large components. As a result, the manufacturing defect rate increases.

[0004] Therefore, in practice, for relatively large and complex components, RBSiC is the mainly selected material as long as the required product characteristics are achieved.

Summary of the Invention

[0005] Therefore, the objective of the present invention is to provide a solution that enables the creation of particularly large and cost-effective parts with lower defect rates, higher dimensional stability, improved hardness, greater strength, superior chemical resistance, and higher temperature stability compared to parts made of RBSiC. Furthermore, the invention aims to contribute to reducing environmental impact and saving material costs by achieving weight reduction while maintaining strength equivalent to that of RBSiC parts, thereby reducing resource consumption.

[0006] The main features of the present invention are described in the feature portion of claim 1, and in claims 23 and 24. Embodiments are described in claims 2 to 22 and claims 25 to 29.

[0007] Regarding a component having a component body made of reaction-bonded silicon carbide (RBSiC), the present invention provides a component body having a surface that is at least partially covered with a coating, wherein the coating is made of silicon carbide (SiC) with a film thickness of at least 25 μm.

[0008] The advantages of this approach are, firstly, as is well known, that the component body made of RBSiC can be manufactured with high dimensional accuracy and a low defect rate. The SiC coating on the body surface improves the surface hardness and chemical resistance of the coated surface area. Furthermore, because the SiC coating acts as a kind of exoskeleton or shell for the component body, for example, the coating improves the strength of the component locally and overall. The coefficients of thermal expansion (CTE) of RBSiC and SiC coatings are similar to each other (the difference is 1 × 10⁻⁶). -5 Because the coefficient of change (W / mK) is less than 300W, even very large RBSiC components can be coated without peeling, achieving unique strength characteristics in integrated systems. In particular, this method makes it possible to provide lightweight yet high-strength components. The amount of RBSiC material used can be reduced, essentially compensated for by the SiC coating. Even with a thickness of just 25 μm, the coating can provide effective protection against the furnace atmosphere and the resulting alloying.

[0009] The component body may, in particular, be a substrate made of reactive-bonded silicon carbide (RBSiC). The substrate is manufactured from an initially porous base material by silicon (Si) infiltration and firing. This makes the substrate strong and airtight. The base material refers to the state before firing, and this preliminary stage includes, for example, SiC powder, carbon, organic additives, and possibly silicon. Infiltration and reaction take place thereafter.

[0010] According to a particular embodiment, the film thickness is at least 50 μm, more preferably at least 100 μm, even more preferably at least 300 μm, and most preferably at least 500 μm.

[0011] As the coating thickness increases, the component strength, in particular, improves further, and the coating exhibits greater durability under chemical and mechanical loads. When the coating thickness exceeds 100 μm, more preferably 300 μm, the SiC coating provides effective protection against, for example, abrasive particles. For example, SiC synthesized by vapor deposition typically exhibits strength values ​​greater than 500 MPa. Therefore, with a SiC coating thickness of 120 μm, the characteristic strength of a standardized RBSiC bending test specimen was improved by 10% compared to the quality without coating, and with a SiC coating thickness of 600 μm, the strength was improved by 50%. In absolute terms, the bending characteristic strength of the coated test specimen reached 306 MPa, compared to 208 MPa for the uncoated test specimen.

[0012] In a more detailed configuration, the main body surface has sub-regions oriented in different spatial directions, and the coating is positioned in at least two of the sub-regions pointing in six spatial directions. This contributes particularly to multidimensional strength enhancement. Depending on the application, the component is subjected to different loads. During the component design process, the region of the component body that receives the greatest load can be identified and reinforced with a SiC layer.

[0013] For components subjected to multidimensional loads, using SiC coatings in multiple spatial directions is particularly useful for component reinforcement. For this purpose, the coatings can be placed in subregions oriented in at least three, preferably at least four, more preferably five, and most preferably all six spatial directions.

[0014] Furthermore, another option is to place the coating on a portion of the surface of the main body that belongs to at least the reinforcing structure of the main body, such as a reinforcing structure consisting of ribs, webs, struts, tension bars, compression bars, honeycomb, rims, or thickened sections.

[0015] In certain embodiments, the reinforcing structure is a skeleton, scaffold, or bionic structure.

[0016] Regarding the coating, the silicon carbide (SiC) in the coating should preferably have a purity of 98%, preferably 99%, and more preferably 99.9%. Purity can be measured by XRF (X-ray fluorescence) analysis and ICP (inductively coupled plasma) spectroscopy. When using such a high-purity SiC coating, relatively inexpensive RBSiC, for example, with a purity of less than 99% (total of Si and SiC), or with impurities exceeding 100 ppm or 1% in the semiconductor field (especially in diffusion furnaces), can be used for the component body. A coating with a minimum thickness of 50 μm reliably prevents impurities from the substrate material from migrating to the highly sensitive silicon wafer. Therefore, for example, paddles, wafer boats, and reactor tubes can be manufactured advantageously. Specifically, even if the total impurity level of the starting materials, i.e., mainly SiC powder and Si powder, is more than 0.5%, preferably less than 5%, more preferably less than 3%, and most preferably less than 1%, it can be used without contaminating the wafer during the process.

[0017] The coating preferably has a film thickness of 2 mm or less. Even with these film thicknesses, it can be applied uniformly and without cracking by technical means, and it performs the desired function. Therefore, the ratio of the advantages of the coating to the manufacturing cost is good. Accordingly, in relation to the part body, the majority of the material weight can consist of RBSiC (the ratio of RBSiC to SiC is greater than 70%, preferably greater than 80%, and more preferably greater than 95%).

[0018] Further optional parameters of the coating include a particle size of 20 μm or less, preferably 10 μm or less, more preferably 7 μm or less, even more preferably 4 μm or less, and most preferably 1 μm or less. This results in good mechanical properties of the coating. The advantage is that, with the appropriate particle size of the coating, the strength of the part is much higher than that of the uncoated part body.

[0019] In the preliminary stage, the particle size of the raw material powder for the component body can be measured using laser diffraction particle size distribution analysis or laser particle size distribution analysis. After the component body and coating are manufactured, and for components manufactured in subsequent processes, the particle size may be calculated using cross-sectional observation and an optical microscope or electron microscope.

[0020] The component body is useful to have an average particle size, particularly an average particle size D50, of at least 25 μm, preferably at least 50 μm, more preferably at least 70 μm, even more preferably at least 90 μm, and most preferably at least 100 μm. This D50 value represents the average particle size. D50 means that 50% of the particles are smaller than the indicated value. The maximum particle size of the component body must be 700 μm.

[0021] According to certain embodiments, the component body has a silicon carbide (SiC) purity of less than 99%. This allows for lower manufacturing costs. The high requirement for material purity can be met on the surface area of ​​the body through appropriate coating.

[0022] The part is particularly advantageous when the part body is at least partially 3D printed, or when the body substrate is at least partially based on a 3D printed part. Such 3D printed parts are characterized by having a body surface with coating steps, particularly along the coating layer. Thus, such parts are identifiable by such steps. The advantage of 3D printed parts is that complex structures made of RBSiC can be efficiently formed by subsequently sintering and firing the printed substrate. These complex structures may be subsequently improved in terms of strength, temperature stability, hardness, and chemical resistance. Even parts that cannot be manufactured entirely from SSiC due to their shape can achieve material properties comparable to SSiC parts in a SiC-coated RBSiC part body. The combination with 3D printing enables numerous new design features, such as improved packing density or reduced heat capacity. Traditionally, it was necessary to use high-purity RBSiC, which was expensive, complex to manufacture, and limited design freedom.

[0023] The 3D printing method is preferably the powder bed method. Powder bed 3D printing generally yields lower bending strength of less than 250 MPa, especially after penetration sintering, compared to RBSiC manufactured by conventional methods, i.e., extrusion molding, compression molding, slip casting, etc. Therefore, in parts manufactured by the 3D printing method, the positive effect of increasing strength due to SiC coating is relatively greater compared to parts made from materials that already have high initial strength.

[0024] Certainly, advantages can be obtained even with a small coating area ratio. However, the properties of improved strength and increased hardness are particularly pronounced at a relatively high coating area ratio of the component body. Therefore, it is possible to have a configuration in which at least 70%, preferably 80%, more preferably at least 85%, more preferably at least 90%, more preferably at least 95%, and very preferably 100% of the component body surface is covered with the coating.

[0025] The coating may specifically be a CVD coating (chemical vapor deposition) or a PVD coating (physical vapor deposition). The CVD coating of SiC reduces the tendency for impurities to precipitate in the case of RBSiC, quartz, or SSiC, and also improves the corrosion resistance of the component body. Therefore, the coating may be a corrosion protection coating.

[0026] High strength is achieved particularly when the coating is consistently configured. With this configuration, a homogeneous microstructure can be achieved particularly within the coating.

[0027] The present invention is particularly directed to - when the component is a satellite carrier, or - when the component is an antenna carrier, or - when the component is a roller for a continuous furnace or a roller furnace, or - when the component is a component of a diffusion furnace or a workpiece holder, for example, a paddle, baffle boat, tube or liner for a diffusion furnace, or - when the component is a burner or radiant tube inside a furnace, or - when the component is a sliding ring or a fitting ring of a sliding ring packing, and is suitable therefor.

[0028] In the case of satellite carriers and antenna carriers, being lightweight and high-strength is particularly an important advantage, especially in space applications. The high hardness of the coating reduces wear, so the sliding ring packing particularly provides low wear characteristics. In furnace applications, there are particularly significant improvements in chemical resistance and temperature stability.

[0029] In another aspect, the present invention relates to the use of a silicon carbide (SiC) coating having a coating thickness of at least 25 μm for coating the body surface of a component body made of reaction-bonded silicon carbide (RBSiC) of a component, and the purpose of the coating is a) To improve the hardness of the main surface of the part, and / or, b) Improve the strength of the part, and / or c) Improve the chemical resistance of the main surface of the component, and / or d) To improve the temperature stability of the components.

[0030] Therefore, coating a component body made of RBSiC with SiC results in reduced defect rates, high dimensional accuracy, and higher strength, improved hardness, better chemical resistance, and temperature stability compared to components made solely of RBSiC, even in large components. The use of silicon carbide (SiC) coatings with a film thickness of at least 25 μm contributes to reducing material usage and enables the construction and manufacture of particularly lightweight components that conserve resources.

[0031] The use of the present invention may optionally encompass the individual device characteristics of the components defined above and below. In particular, the use may optionally relate to the technical characteristics of the coating, independently of the components and the component body, as defined above and below.

[0032] The present invention further, a) a. A powder-based substrate (green body) is manufactured from silicon carbide (SiC) and a carbon source. b. The substrate is subjected to reaction firing while impregnating it with silicon (Si) to produce a base body made of reaction-bonded silicon carbide (RBSiC), thereby manufacturing the main body of the component. b) The step of coating the main surface of the component body with a silicon carbide (SiC) coating having a film thickness of at least 25 μm, This relates to a method for manufacturing parts that include [specific components].

[0033] Coating a component body or substrate made of methodologically advantageous RBSiC with SiC results in reduced defect rates, higher dimensional accuracy, and greater strength, increased hardness, improved chemical resistance, and improved high-temperature stability compared to components made solely of RBSiC, even for large components. This method contributes to reducing material usage and enables the construction and manufacture of particularly lightweight components that conserve resources.

[0034] A carbon source in a powder-based substrate can be introduced, for example, by an impregnation process to incorporate free carbon (C) into a powder-based preliminary substrate made of silicon carbide (SiC).

[0035] The method of the present invention may optionally be implemented to achieve the individual device characteristics of the components specified above and below.

[0036] In particular, this method may provide a configuration in which the main body surface has a portion region oriented in different spatial directions, and a coating is applied to the portion region that points to at least two of the six spatial directions. This improves the component characteristics in multiple spatial directions.

[0037] In one configuration of this method, the main surface of the part to be coated is polished at least partially or completely before coating. This improves the flatness of the coating. This leads to improved coating strength against bending stress and tensile stress, and prevents cracking of the coating. Polishing is particularly effective in preventing surface roughness from causing a notch effect on the coating. Furthermore, this allows for the selection of a more economical and thinner coating thickness.

[0038] The base material is optionally manufactured by 3D printing. In this case, the carbon source may be introduced after 3D printing, for example, by impregnation into the printed part. This technique allows for the creation of complex and bionic structures. The 3D printing method is preferably a powder bed method. After printing, impregnation and firing are required to impregnate the printed base material with silicon (Si). This increases the density and strength of the part body.

[0039] Coating methods using CVD (chemical vapor deposition) or PVD (physical vapor deposition) are particularly advantageous. This allows even complex component structures to be uniformly coated using a simple method. Areas of the component body that are not to be coated may optionally be covered with a mask.

[0040] In particular, this method may provide a method for constructing a coating in accordance with the above and subsequent descriptions. The advantages shown in each section should be mentioned here.

[0041] The advantageous aspects of the invention will be described in more detail through numerous examples.

[0042] (RBSiC roller) When RBSiC rollers are coated with CVD-SiC to a thickness of at least 25 μm, preferably at least 50 μm, they can be protected from highly aggressive or corrosive media, such as those generated during the firing of cathode materials for the manufacture of lithium-ion batteries. Commonly used materials include cobalt, nickel, aluminum, manganese, and lithium. When conventional RBSiC rollers are used, these materials tend to form alloys with Si, creating partial eutectic formations that reduce durability. Furthermore, wear from frequently used cordierite or mullite crucibles generates highly abrasive particles that erode the rollers and shorten their lifespan. Additionally, the highly aggressive or corrosive furnace atmosphere formed during material firing also shortens the lifespan of RBSiC rollers.

[0043] Applying a coating thicker than 25 μm, more preferably thicker than 50 μm, provides effective protection against the furnace atmosphere and alloy formation, while a coating thicker than 100 μm, even more preferably thicker than 300 μm, also provides efficient protection against abrasive particles. Overall, this method significantly extends the durability of the roller. At the same time, using low-purity powder for the RBSiC component body significantly reduces the manufacturing cost of the part. Increasing the coating thickness also improves the strength of the roller, resulting in a smaller cross-sectional area than in the case of RBSiC, for example, by 10%. This reduces the heat capacity in the furnace. As an alternative, pure silicon carbide rollers (SSiC) can be used, but they are significantly more expensive than RBSiC components with a SiC coating.

[0044] (Components for the space industry) A further highly advantageous application of this invention is the space industry. Given the complex load generation scenarios and the need for extreme weight reduction, i.e., optimized design, the ability to 3D print the base material is particularly advantageous here. Thus, it becomes possible to create bionic structures that combine high rigidity and strength with low weight (e.g., 30% lighter than a comparable aluminum structure). Considering the strength improvement achieved by SiC coatings applied by methods such as CVD, it is possible to reduce the mass of the structure (reduced wall thickness, more complex web structures, etc.) or further strengthen existing designs. This effect is also applicable to simple shapes using other molding methods. An advantage here is that tensile stress, which is the greatest load for ceramics, always occurs on the outside of the part (the so-called outer layer fibers). If this outer part is composed of a higher strength material, the overall strength of the part is improved. By using a fine CVD-SiC coating with high purity (higher than 95%, more preferably higher than 99%) and a particle size of less than 20 μm, more preferably less than 10 μm, and even more preferably less than 1 μm, the overall strength of the part can be significantly improved.

[0045] (Cantilever paddle for diffusion furnace) The ceramic body based on reaction-bonded composite material is substantially composed of SiC and free Si and is manufactured by a powder bed 3D printing method as follows: It is constructed layer by layer from amorphous particle aggregates of SiC, and the powder is based on a particle size distribution known for technical refractory ceramics referred to as 100 / F. Thus, the characteristic values ​​are d10=75μm, d50=115μm, and d90=160μm. Selective solidification of the particles is achieved by dropwise injection of an organic binder, preferably furan resin, applied via an inkjet print head at positions indicated by the underlying CAD model. The CAD model used here corresponds to the final part shape and can generate structures with complex shapes. Following these two separate steps, the construction field plane is reduced by a predefined layer thickness, for example, 300μm. This series of steps is repeated iteratively until the layer-by-layer implementation of the CAD model is complete. The resulting complex-shaped preparatory material has approximately 45% by volume porosity and is then impregnated with an aqueous dispersion consisting of 30% by weight colloidal carbon, a dispersion aid, and a wetting agent. After the initial impregnation operation, a complex-shaped ceramic preparatory material is thus obtained, which consists of approximately 87% by weight of the original SiC powder and approximately 13% by weight of colloidal carbon. After the drying process and, if necessary, a second impregnation step, this ratio changes to 79 / 21% by weight, and further to 76 / 24% by weight after a third impregnation step. Depending on the size of the paddle, it may be useful to pre-segment the paddle and print it into multiple parts, preferably two parts, and then impregnate them (i.e., carbon concentrate) as described herein. After each drying, these partial segments need to be joined together using an organic auxiliary agent (known to those skilled in the art as assembly). In an additional manufacturing variation using this joining technique, the paddle can be segmented, with one segment manufactured using an alternative molding method such as extrusion, and the other segments of the paddle with complex shapes manufactured using the 3D printing method described herein. This segmentation method reduces manufacturing costs as long as each molding method can be used cost-effectively according to its specific advantages.

[0046] After the final drying process, the complex-shaped pre-forms (green bodies) obtained through any of the manufacturing routes described here are converted by reaction firing into ceramic component bodies based on a reaction-bonded composite material mainly composed of SiC and free Si. Once this reaction firing is complete, the joints between segments become indistinguishable to the naked eye, resulting in the production of a quasi-monolithic component. This component is then coated with SiC by chemical vapor deposition (CVD), preferably with a crystalline SiC coating thickness between 150 μm and 600 μm. The resulting complex-shaped and coated cantilever paddles can be used to insert and remove semiconductor "wafer boats" into so-called diffusion furnaces or general in-furnace reactors. Furthermore, using CVD-SiC coating has the advantage of allowing the production of component bodies using relatively low-purity SiC, Si, and C raw materials. The impurities in these raw materials are mainly compounds of elements such as V, Ti, Al, Fe, Na, Ca, Zr, Cu, and Ni, with a total impurity content of up to 3% by weight, and in some cases reaching 5% by weight. CVD-SiC coating prevents these impurities from penetrating the process vessel, eliminating contamination of the wafers being processed.

[0047] (Conveyor rollers for roller furnaces manufactured by extrusion) Ceramic bodies based on a reaction-bonded composite material substantially composed of SiC and free Si are manufactured by extrusion as follows. A plastic lump mainly consisting of SiC powder with an average particle size of 40 μm, carbon with an average particle size of less than 1 μm, and an organic additive for plasticization is extruded by an extruder at an extrusion pressure of 40 to 55 bar to obtain an extruded product having a tubular cross-section. Here, the inner and outer diameters can be varied in the range of 10 mm to 80 mm, and the roller length is up to 5000 mm. After molding is complete, the cylindrical preform obtained by any of the manufacturing routes described here is converted by reaction firing into a ceramic component body based on a reaction-bonded composite material substantially composed of SiC and free Si. This component body is then coated with SiC by chemical vapor deposition (CVD), preferably with a crystalline SiC coating thickness between 150 μm and 800 μm. The resulting CVD-coated rollers exhibit increased rigidity, reduced deflection under load, and improved bending strength and long-term stability compared to conventional uncoated rollers based on RBSiC. Furthermore, the coated rollers have significantly improved corrosion resistance and wear resistance, making them particularly suitable for use in roller furnaces for firing CAM (cathode active materials, i.e., RBSiC corrosive metal oxides or phosphates based on lithium, nickel, cobalt, manganese, aluminum, iron, and other elements).

[0048] (Mirror manufactured using 3D printing) Ceramic bodies based on a reaction-bonded composite material substantially composed of SiC and free Si are manufactured by powder bed 3D printing. In this way, a hollow mirror structure with a topologically optimized rib structure of complex shapes, such as a honeycomb structure, is realized on the back side of the mirror surface, thereby providing high specific stiffness and strength to the entire structure while simultaneously minimizing weight. By utilizing the above bonding method and subsequent reaction firing, monolithic mirror structures up to, for example, 2500 mm in diameter can be manufactured. After reaction firing is complete, the mirror structure (part body) based on the reaction-bonded composite material substantially composed of SiC and free Si is pre-polished as needed and then coated with SiC by chemical vapor deposition (CVD), preferably with a crystalline SiC coating thickness in the range of 150 μm to 2000 μm. The resulting CVD-coated mirror structure, in particular, that includes a coated reinforcing structure or rib structure, provides higher specific stiffness and strength than conventional RBSiC structures. Furthermore, a SiC surface formed by CVD, which is at least substantially free of defects and pores, can be used to achieve a uniform optical surface with a square roughness of less than 5 Å and a polishing quality of P2 or P3.

[0049] (Frame structure manufactured using 3D printing) A ceramic body based on a reaction-bonded composite material substantially composed of SiC and free Si is manufactured using a powder bed 3D printing method. This enables the creation of geometrically complex frame structures required in coordinate measuring instruments and semiconductor technology fields, particularly in EUV lithography equipment. The adoption of 3D printing allows for the creation of shapes that are lighter or even topologically optimized compared to conventional machining methods. By using the aforementioned bonding method and subsequent reaction firing, it is possible to manufacture extra-large monolithic frame structures with edge lengths reaching 2000 mm. After reaction firing, the frame structure based on the reaction-bonded composite material substantially composed of SiC and free Si is coated with SiC by chemical vapor deposition (CVD), preferably with a crystalline SiC coating thickness in the range of 150 μm to 1000 μm. The resulting CVD-coated frame structure has improved specific stiffness and strength compared to conventionally manufactured RBSiC frame structures. This particularly advantageously meets the stringent stiffness and strength requirements imposed on this type of frame structure in applications in EUV lithography and industrial measurement fields. In particular, for frame structures used in EUV lithography, SiC-CVD coatings are extremely suitable for preventing the separation of impurities and particles from the substrate into the sensitive cleanroom process environment. A particularly advantageous aspect in this regard is the high adhesive tensile strength of the SiC coating on the RBSiC substrate surface.

[0050] (Other usage examples) Examples of use of the described invention include frame structures for mounting optical components (so-called "optical benches") and measurement systems. Further examples of applications in the field of mechanical engineering include quills, air slide bearings, and frame structures. These components may be applied, for example, to CMM (coordinate measuring machine) systems, lithography equipment, or similar precision machinery. Furthermore, coated components may be used in wafer chucks, wafer tables, or other components that come into contact with wafers. In this case, it is advantageous to focus on high mechanical strength as well as high purity of the coating (higher than 99%, more preferably higher than 99.9%), which prevents wafer contamination. This allows the use of RBSiC-based materials, which may have significantly lower purity, in the component body.

[0051] Other features, details, and advantages of the present invention are also evident from the wording of the claims and the description of exemplary embodiments with reference to the drawings. [Brief explanation of the drawing]

[0052] [Figure 1] This figure shows a component body made of RBSiC and a component having a SiC coating, specifically a cantilever paddle. [Figure 2] This figure shows a component body made of RBSiC and a component having a SiC coating, specifically a conveyor roller for a roller furnace. [Figure 3] This figure shows a component body made of RBSiC and a component having a SiC coating, specifically a plate having a bionic reinforcement structure on its back surface. [Figure 4] This figure shows a component body made of RBSiC and a component having a SiC coating, specifically a hollow mirror. [Figure 5] This figure shows a component body made of RBSiC and a component having a SiC coating, specifically a frame structure. [Modes for carrying out the invention]

[0053] Figures 1 to 5 each show a component 1 having a component body 2 made of reaction-bonded silicon carbide (RBSiC), the component body having a surface 3 completely covered with a coating 4. The integrally molded silicon carbide (SiC) coating 4 has a film thickness of at least 25 μm. Furthermore, in each of Figures 1 to 5, a schematic cross-section is shown at position AA, and the same reference numeral is used.

[0054] It can be confirmed that there are sub-regions on the main body surface 3 oriented in different spatial directions, and the coating 4 is applied to all six sub-regions pointing in all spatial directions. As shown in Figures 1 and 3 to 5, this includes sub-regions on the main body surface 3 that belong to the reinforcing structure 5 of the component body 2 in the form of ribs, rims, or lattice structures. Only the conveyor roller shown in Figure 2 does not have such a reinforcing structure.

[0055] Coating 4 preferably has the following further properties. - The silicon carbide (SiC) in coating 4 should have a purity of 98%, preferably 99%, and more preferably 99.9%. - Coating 4 should have a film thickness of 2 mm or less. - Coating 4 should have a particle size of 20 μm or less, preferably 10 μm or less, more preferably 7 μm or less, even more preferably 4 μm or less, and most preferably 1 μm or less. - Coating 4 should be a CVD coating or a PVD coating.

[0056] The component body 2 preferably has the following further characteristics. - The component body 2 should have an average particle size of at least 10 μm, preferably at least 50 μm, more preferably at least 70 μm, even more preferably at least 90 μm, and most preferably at least 100 μm. - Component body 2 must have a purity of absolutely less than 99%.

[0057] The left-hand region of part 1 shown in Figure 1 is embodied as a round bar or tube. In the manufacturing method, this region of part body 2 may be manufactured by continuous casting. The right-hand region of part 1 has a more complex structure with angles, reinforcing structures 5 and holes. This part of part body 2 may be a 3D printed part. The two parts of part body 1 can be joined later by assembly and reaction firing of part body 2.

[0058] Component 1 shown in Figure 1 is a workpiece holder for a diffusion furnace, more specifically called a cantilever paddle. Here, coating 4 simultaneously serves as a corrosion-resistant coating, purity coating, strength coating, wear-resistant coating, and temperature-stabilizing coating.

[0059] The component shown in Figure 2 is a conveyor roller for a diffusion furnace. The component body 2 is covered with a coating 4. The peripheral edge of the coating 4 forms the rolling surface of the roller. The inner portion of the coating 4, in particular, functions as a coating to prevent deposits from the component body 2 and to reinforce the component body 2.

[0060] Similarly, the reinforcing structure 5 shown in Figure 3 also has an outer region and an inner region of the coating 4. As a result, the arm portion of the reinforcing structure 5 is stabilized on both the inside and outside by the coating 4.

[0061] In the case of the hollow mirror shown in Figure 4, the coating of the back surface reinforcement structure 5 is particularly important. This contributes to the high thermal stability and shape conformability of the hollow mirror. The concave surface of the hollow mirror may also be provided with a similar coating 4 as needed, as shown in the figure.

[0062] The frame structure shown in Figure 5 is a very complex component with extensive reinforcing structures, fastening surfaces, and mounting points.

[0063] The present invention is not limited to any of the embodiments described above and may be modified in various ways.

[0064] All features and advantages evident from the claims, detailed description and drawings, including structural details, spatial arrangement and method steps, may be essential to the present invention, both individually and in a wide variety of combinations. [Explanation of symbols]

[0065] 1 part 2. Main body of the component 3. Main body surface 4 Coating 5. Reinforcement structure

Claims

1. A component (1) having a component body (2) made of reaction-bonded silicon carbide (RBSiC), the component body (2) having a body surface (3) that is at least partially covered with a coating (4), and the coating (4) being made of silicon carbide (SiC) with a film thickness of at least 25 μm.

2. The part (1) according to claim 1, wherein the thickness of the coating is at least 50 μm, more preferably at least 100 μm, even more preferably at least 300 μm, and most preferably at least 500 μm.

3. The component (1) according to claim 1 or claim 2, wherein the main body surface (3) has partial regions oriented in different spatial directions, and the coating (4) is arranged in at least partial regions that point to at least two of the six spatial directions.

4. The component (1) according to claim 3, wherein the coating (4) is arranged in a partial region that points to at least three of the six spatial directions, preferably at least four of the six spatial directions, more preferably five of the six spatial directions, and even more preferably all six spatial directions.

5. The part (1) according to any one of claims 1 to 4, wherein the coating (4) is disposed in at least a portion of the surface (3) of the part body (2) that belongs to the reinforcing structure (5), for example, a rib, web, strut, tension bar, compression bar, honeycomb, rim, or thickened portion.

6. The component (1) according to claim 5, wherein the reinforcing structure (5) is a skeleton, scaffold, or bionic structure.

7. The component (1) according to any one of claims 1 to 6, wherein the silicon carbide (SiC) of the coating (4) has a purity of 98%, preferably 99%, and more preferably 99.9%.

8. The part (1) according to any one of claims 1 to 7, wherein the coating (4) has a film thickness of 2 mm or less.

9. The component (1) according to any one of claims 1 to 8, wherein the coating (4) has a particle size of 20 μm or less, preferably 10 μm or less, more preferably 7 μm or less, even more preferably 4 μm or less, and most preferably 1 μm or less.

10. The component (1) according to any one of claims 1 to 9, wherein the component body (2) has an average particle size of at least 25 μm, preferably at least 50 μm, more preferably at least 70 μm, even more preferably at least 90 μm, and most preferably at least 100 μm.

11. The component (1) according to any one of claims 1 to 10, wherein the component body (2) has a silicon carbide (SiC) purity level of less than 99%.

12. The part (1) according to any one of claims 1 to 11, wherein the part body (2) is at least partially a 3D printed part, or the base material of the part body (2) is based at least partially a 3D printed part.

13. The component (1) according to any one of claims 1 to 12, wherein at least 70%, preferably 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, and very preferably 100% of the main body surface (3) is covered with a coating (4).

14. The component (1) according to any one of claims 1 to 13, wherein the coating (4) is a CVD coating or a PVD coating.

15. The component (1) according to any one of claims 1 to 14, wherein the coating (4) is a corrosion-resistant coating.

16. The component (1) according to any one of claims 1 to 15, wherein the coating (4) is consistently formed.

17. The component (1) according to any one of claims 1 to 16, wherein the component (1) is a satellite carrier.

18. The component (1) according to any one of claims 1 to 16, wherein the component is an antenna carrier.

19. The part (1) according to any one of claims 1 to 16, wherein the part (1) is a roller for a continuous furnace or a roller furnace.

20. The component (1) according to any one of claims 1 to 16, wherein the component (1) is a component of a diffusion furnace or a workpiece holder.

21. The component (1) according to any one of claims 1 to 16, wherein the component (1) is a burner or a radiating tube in a furnace.

22. The part (1) according to any one of claims 1 to 16, wherein the part (1) is a slide ring or a fitting ring of a slide ring packing.

23. The use of a silicon carbide (SiC) coating (4) having a film thickness of at least 25 μm for covering the main body surface (3) of the component body (2) of component (1), which is made of reaction-bonded silicon carbide (RBSiC), a) To improve the hardness of the main body surface (3) of the part (1), and / or b) To improve the strength of the part (1), and / or c) To improve the chemical resistance of the main body surface (3) of the part (1), and / or d) Use to improve the temperature stability of the component (1).

24. a) a. A powder-based substrate is manufactured from silicon carbide (SiC) and a carbon source; b. The substrate is subjected to reaction firing while being impregnated with silicon (Si) to produce a substrate made of reaction-bonded silicon carbide (RBSiC), thereby manufacturing the main body of the component (2); b) The step of covering at least a portion of the main body surface (3) of the component body (2) with a silicon carbide (SiC) coating (4) having a film thickness of at least 25 μm, A method for manufacturing a component (1), including the component (1).

25. The method according to claim 24, wherein the main body surface (3) has partial regions oriented in different spatial directions, and the coating (4) is applied to at least partial regions that point to at least two of the six spatial directions.

26. The method according to claim 24 or 25, wherein the body surface (3) of the part body (2) to be covered is polished at least partially or completely before covering.

27. The method according to any one of claims 24 to 26, wherein the base material is manufactured by printing using a 3D printing method.

28. The method according to any one of claims 24 to 27, wherein the coating is performed by CVD or PVD.

29. The method according to any one of claims 24 to 28, wherein the component (1) has the configuration described in any one of claims 1 to 22.

Images