Method for manufacturing nano-doped sic fiber-ceramic powder composite heating element

Abstract

The present invention relates to a method for manufacturing a nano-doped SiC fiber-ceramic composite heating element, comprising the steps of: uniformly mixing infusible PCS fibers with ceramic powder while simultaneously charging same into a mold; and heat-treating the mixture of infusible PCS fibers and ceramic powder at 1000°C to 1350°C in an inert atmosphere. According to the present invention, it is possible to easily and economically manufacture a new concept of a nano-doped SiC fiber-ceramic powder composite for a heat exchanger, which enables effective heating, heat storage, and effective heating of a fluid (water) in a pipe, by fusing SiC fibers, which absorb microwaves and convert same into Joule heat to enable a very fast heating rate, high heating temperature, and a clean heating element, with ceramic powder, which has a high specific heat and thus boasts a heat storage performance that retains heat for a relatively long time and a good radiation rate, thereby effectively heating an object to be heated at a long distance.

Description

Method for manufacturing a nano-doped SiC fiber and ceramic powder composite heating element

[0001] The present invention relates to a method for manufacturing a heating element by fusing SiC fibers exhibiting high strength at ultra-high temperatures with ceramics having good heat storage and excellent radiation functions, and more specifically, to a method for manufacturing a new concept of a clean and high-efficiency nano-doped SiC fiber / ceramic powder fusion heating element for a heat exchanger, which comprises fusing SiC fibers and ceramic powders by arranging them regularly and uniformly to manufacture a fusion material, and the manufactured nano-doped SiC fiber / ceramic powder fusion material has 1) microwave absorption and heat generation characteristics, 2) heat storage characteristics that maintain temperature for a long time, and 3) good radiation characteristics that enable heating of a relatively distant object to be heated.

[0002] SiC fibers are manufactured in an inert atmosphere at 1300 to 2000 degrees Celsius. Because of their excellent ultra-high temperature mechanical properties, they have been widely used in various fields, including aerospace engines, internal structural materials for nuclear power plants, turbine blades for thermal power plants, brake pads / discs for sports cars, internal components for guided weapons, and semiconductor tools.

[0003] Another unique characteristic of SiC fibers is their ability to absorb microwaves and convert the absorbed microwave energy into Joule heat, generating heat. SiC has traditionally been used as a Joule heat source, typically using electrical resistance. Furthermore, microwave irradiation has been used as a source of heat, but their large size and weight make it time-consuming to reach the desired temperature, making precise temperature rises relatively difficult. In contrast, SiC fibers are extremely small, measuring only 10–15 μm in diameter. This small size and weight allow them to absorb external microwaves, converting them into Joule heat, and rapidly heat the target. This allows for rapid temperature rise at the SiC fiber surface. Consequently, the heat conversion response to microwaves is extremely fast, enabling precise temperature control. Furthermore, the ultra-thin SiC fibers offer the advantage of rapid heating and cooling simultaneously. However, in order to be applied to heat exchangers, etc., the fluid (water) flowing inside the pipe must be heated and the heat must be accumulated (heat storage) for a long period of time to have commercial value. Therefore, the present invention proposes a new concept of a fusion heating element by uniformly fusing ceramic powder, which has a high emissivity to effectively heat the fluid (water) flowing inside the pipe and a relatively high specific heat to store heat for a long period of time, with SiC fibers.

[0004] The problem to be solved by the present invention is to provide a SiC fiber / ceramic powder fusion composite heating element easily in a single process by infusifying polymer PCS fibers, uniformly mixing the infusible PCS fiber bundles with ceramic powder, fusing them, and then putting them into a mold (frame) in the shape of a heating element such as a circle, a line, a plate, etc., and heat-treating them, and to provide a nano-doped SiC fiber / ceramic fusion heating element capable of efficiently heating a fluid (water) inside a pipe and maintaining the temperature for a long time, and a method for manufacturing a heat exchanger using the same.

[0005] One embodiment of the present invention for solving the above problem provides a method for manufacturing a nano-doped SiC fiber / ceramic powder composite heating element, characterized by including the steps of infusifying and doping PCS fibers with iodine gas; and the step of uniformly mixing PCS fibers manufactured with infusible and doped PCS with ceramic powder.

[0006] In addition, another embodiment of the present invention provides a method for manufacturing a nano-doped SiC fiber / ceramic powder composite heating element, characterized in that it includes a step of placing a mixture of infusible PCS fiber and ceramic powder according to the above method into a mold in the shape of a heating element and heat-treating the mixture at 1000 to 1350°C in an inert atmosphere.

[0007] In addition, another embodiment of the present invention provides a method for manufacturing a nano-doped SiC fiber / ceramic powder composite heating element, characterized in that it includes a step of controlling thickness and density by pressing an infusible PCS fiber and ceramic powder mixture contained in a mold with a constant load so as to have a desired degree of porosity and density in the mold during manufacturing according to the above method.

[0008] According to the present invention, the nano-doped SiC fiber / ceramic composite heating element manufactured has a heating rate that is 100 times faster than that of a conventional SiC material (block) heating element and a temperature rise of close to 1500°C, and exhibits very efficient heating behavior. In addition, it is very clean as it does not generate CO2 gas due to conversion into Joule heat after microwave absorption.

[0009] And, due to the heat storage characteristics of the fused ceramic powder, it can maintain heat for a relatively long time, and due to the excellent radiation characteristics of the ceramic powder, it can present a new concept of a heating element that can effectively heat the fluid (water) inside the pipe.

[0010] In addition, in the present invention, a nano-doped SiC fiber / ceramic powder composite heating element is manufactured by mixing the starting raw material PCS fiber with ceramic powder after infusing it, loading it into a mold in the shape of a heating element, and then pressing it with a constant load while performing heat treatment. This allows for the manufacture of a nano-doped SiC fiber / ceramic powder composite heating element for a heat exchanger through a very simple and convenient process, and at the same time, the shape of the mold used in the heat treatment can be applied in various ways to more quickly respond to the required heating element shape.

[0011] FIG. 1 is a process diagram for manufacturing a nano-doped SiC fiber / ceramic powder composite heating element according to one embodiment of the present invention.

[0012] FIG. 2 is a schematic diagram of a nano-doped SiC fiber / ceramic powder composite heating element according to one embodiment of the present invention.

[0013] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings in order to describe in detail to an extent that those skilled in the art to which the present invention pertains can easily practice the technical idea of ​​the present invention. In the following description, many specific details, such as specific components, are shown, but these are provided only to help a more general understanding of the present invention, and it will be obvious to those skilled in the art that the present invention can be practiced without these specific details. In addition, in describing the present invention, if it is determined that a specific description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

[0014] Fig. 1 is a process diagram for manufacturing a nano-doped SiC fiber / ceramic powder composite heating element according to an embodiment of the present invention. Fig. 2 is a schematic diagram of a nano-doped SiC fiber / ceramic powder composite heating element according to an embodiment of the present invention.

[0015] Referring to FIGS. 1 and 2, a method for manufacturing a nano-doped SiC fiber / ceramic powder composite heater according to an embodiment of the present invention includes the steps of infusifying and doping PCS fibers with iodine gas; and the step of uniformly mixing PCS fibers manufactured with infusible and doped PCS and ceramic powder. In addition, a method for manufacturing a nano-doped SiC fiber / ceramic powder composite heater according to another embodiment of the present invention includes the step of placing a mixture of infusible PCS fibers and ceramic powders according to the above method into a mold in the shape of a heater and heat-treating the mixture at 1000 to 1350°C under an inert atmosphere. In addition, a method for manufacturing a nano-doped SiC fiber / ceramic powder composite heater according to another embodiment of the present invention includes a step of controlling thickness, density, etc. by pressing an infused PCS fiber and ceramic powder mixture contained in a mold with a constant load to have a desired degree of porosity and density in the mold during manufacturing according to the method.

[0016] Hereinafter, a method for manufacturing a nano-doped SiC fiber / ceramic powder composite heating element according to the present invention described above will be described in more detail. First, a polymer, PCS (molecular weight Mw = 3000 to 4000), is melt-spun to manufacture PCS fibers using a conventional method. The manufactured PCS fibers are placed in a heating chamber to heat them to around 200 to 300°C in a nitrogen atmosphere. At this time, a certain amount of solid iodine is also added and heated to around 200 to 300°C in a nitrogen atmosphere. When the temperature is heated to around 200 to 300°C, the iodine gasifies and reacts and enters the PCS fibers, inducing infusibility of the PCS fibers and ultimately remaining doped after heat treatment.

[0017] After the above process, the infusible PCS fiber is placed in a mold of a certain shape and heat-treated at 1000 to 1350°C in an inert atmosphere to undergo a thermal decomposition process and convert the polymer PCS fiber into SiC fiber. At this time, when the PCS fiber is placed in the mold of a certain shape, the ceramic powder is placed so as to be uniformly mixed at the same time to form a mixture of the infusible PCS fiber and the ceramic powder.

[0018] The above mold can be used in various ways to have a heating element shape suitable for various cylindrical heat exchangers, and in the step of charging and mixing the infusible PCS fiber and ceramic powder into the mold, the weight ratio of the infusible PCS fiber and ceramic powder can be adjusted in various ways from 90:10 to 10:90. In addition, the type of ceramic powder used in the step of charging and mixing the infusible PCS fiber and ceramic powder into the mold can be various ceramic powders such as garnet, yellow clay, and mace, which have excellent far-infrared radiation effects.

[0019] Thereafter, in order to manufacture a nano-doped SiC fiber / ceramic composite heater with a desired microstructure, degree of density, weight, shape, thickness, etc., the infusible PCS fiber and ceramic mixture loaded into a mold is heat-treated while controlling the load from the upper side to the lower side of the mold to obtain the desired nano-doped SiC fiber / ceramic composite heater shape. For example, after loading the infusible PCS fiber and ceramic mixture into the inner space of a mold with an open upper side, an upper mold is placed on the open upper side of the mold, and then a compressive load applied to the upper mold from the upper side to the lower side is applied or controlled to control the compressive strength reached by the infusible PCS fiber and ceramic mixture.

[0020] The nano-doped SiC fiber / ceramic composite heating element manufactured as described above can be manufactured in a shape suitable for manufacturing a heat exchanger, such as various cylindrical shapes, to manufacture a nano-doped SiC fiber / ceramic composite heating element optimized for a heat exchanger with rapid temperature increase, clean heat exchange, excellent radiant heating, and relatively long-term heat storage function.

[0021] The present invention is not limited to the specific preferred embodiments described above, and anyone with ordinary skill in the art to which the invention pertains can make various modifications without departing from the gist of the present invention claimed in the claims, and such modifications are within the scope of the claims.

Claims

1. A method for manufacturing a nano-doped SiC fiber and ceramic powder composite heating element, comprising: a step of infusifying and doping PCS fibers with iodine gas; and a step of uniformly mixing the infusible and doped PCS fibers and ceramic powder, characterized in that, in the mixing step, a compressive load is applied to the mixture in which the infusible PCS fibers and ceramic powder are mixed.

2. In paragraph 1, A method for manufacturing a nano-doped SiC fiber and ceramic powder composite heating element, characterized in that the above mixing step is a step of mixing infusible PCS fiber and ceramic powder while charging them into a mold in the shape of a heating element for a heat exchanger.

3. In paragraph 1, The above mixing step is characterized by including a step of putting a mixture of the above infusible PCS fiber and ceramic powder into a mold in the shape of a heating body and heat-treating it at 1000 to 1350°C under an inert atmosphere. A method for manufacturing a nano-doped SiC fiber and ceramic powder composite heating body 4. In any one of paragraphs 1 to 3, A method for manufacturing a nano-doped SiC fiber and ceramic powder composite heating element, characterized in that the type of the above ceramic powder includes at least one of garnet, loess, and feldspar.

5. In any one of paragraphs 1 to 3, A method for manufacturing a nano-doped SiC fiber and ceramic powder composite heating element, characterized in that the weight ratio of the infused PCS fiber and the ceramic powder is controlled within a range of 90:10 to 10:

90.

6. In paragraph 1, The above manufacturing method is a method for manufacturing a nano-doped SiC fiber and ceramic powder composite heating element, characterized in that a compressive load is applied to a mixture of the above infusible PCS fiber and ceramic powder while heat-treating the mixture under an inert atmosphere.

7. In paragraph 2 or 3, A method for manufacturing a nano-doped SiC fiber and ceramic powder composite heating element, characterized in that the mold includes at least one cylindrical shape as a heating element shape suitable for a heat exchanger.

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