WO2016208846A1 - Method for producing silicon carbide fiber, silicon carbide fiber and silicon carbide fiber heating element produced thereby, and heating device using same - Google Patents

Abstract

The present invention relates to a method for directly producing silicon carbide fiber and metal doped silicon carbide fiber by converting carbide fiber into the silicon carbide fiber and the metal doped silicon carbide fiber through a gas infiltration reaction at high temperature simpler than a conventional production process. More particularly, the present invention relates to a method for producing silicon carbide fiber and metal doped silicon carbide fiber through a sublimation step at high temperature and a step of disposing additional metal elements, silicon carbide fiber produced thereby, and an application of a silicon carbide fiber heating element and a heating device using the same, etc. According to the present invention, the production process is simple, and it is possible to continuously produce crystalline silicon carbide fiber which has low oxygen content and excellent physical properties. In particular, it is possible to produce metal doped silicon carbide fiber with improved oxidation resistance, thermal resistance, etc.

Description

Method for manufacturing silicon carbide fiber, thereby silicon carbide fiber, silicon carbide fiber heating element, and heating device using the same

The present invention relates to a method for producing silicon carbide fibers (SiCf) and the application of the silicon carbide fibers,

More specifically, carbon fibers may be formed by sublimation of a sublimation raw material selected from, for example, silicon or silicon dioxide, or a mixture thereof at a high temperature, by a sublimation gas infiltration reaction. Provides a method for producing silicon carbide fibers (SiCf), silicon carbide fibers and silicon carbide fiber heating elements, and other applications,

Further sublimation further comprises a doping source to provide nano-doped silicon carbide fibers and heating elements using the same,

The present invention relates to a rapid heating highly efficient silicon carbide fiber heating element capable of minimizing the loss of thermal heat energy and a heating device using the same.

Silicon carbide (SiC) fiber is a representative non-oxide-based ceramic material and has excellent physicochemical stability at high temperatures, and is being used in composite materials fields such as aerospace, energy, and defense.

In particular, it is the only fiber that can be used above 1,000 oC in air and is used in CFCC or CMC (Continuous Fiber Reinforced Ceramic Matrix Composites) that require high temperature process. Sensitivity, foreign matter collision resistance, etc. are improved, as well as the bonding with peripheral parts is improved, a breakthrough material that can produce large parts as a single body, it is expected to be applied as a high reliability heat-resistant material.

The existing SiC fiber manufacturing process is made by three methods, powder extrusion (Carborundum), CVD (Chemical Vapor Deposition), precursor method.

In the powder extrusion method, a submicron SiC powder (SiC Powders) and a sintering aid were mixed together with a suitable polymer to make a compound capable of melt spinning, and then extruded to a desired diameter and sintered at 2,000 oC to prepare SiC fibers. Among the fibers developed to date, creep resistance is the most excellent fiber.

However, due to the large size of SiC particles in the fibers and the presence of pores, their production is discontinued due to their low strength, easily broken and unwieldy properties.

The CVD method transfers core wire (tungsten wire or carbon fiber) through the Mercury Contact at a constant speed into the quartz reaction tube, and flows current through the injected core wire and heats it by 1,000 ~ 1,300 oC by self-heating, and is a raw material of methyldichlorosilane It is prepared by depositing SiC by adding silane gas such as (Methyl Dichlorosilane) and Ar, H2 gas, which are atmospheric gases.

This manufacturing method is a method of coating the SiC on the surface of the core wire is superior in thermal stability than other fibers, but the manufacturing process is difficult and the manufacturing cost is high.

In particular, coarse fibers are manufactured with a diameter of 150 um or more, which is not suitable for the application of fiber reinforced composite materials. SCS SiC Fibers: Process, Properties and Production Technical Data from the Website fo Specialty Materials, www. specmaterials. com]

The precursor method is a process for producing SiC fibers having a diameter of 10 to 100 um through melt spinning and pyrolysis of a polycarbosilane (PCS) precursor which is an organosilicon polymer.

The general PCS manufacturing method is mainly a high temperature pressurization reaction using autoclave using dimethyldichlorosilane (DMDS) as a starting material.

However, in the PCS manufacturing process, pyrolysis by-products such as CH4, H2, MeSiH3, Me2SiH, Me3SiH, etc. are generated, and the internal pressure of the autoclave increases over 100 atm during the reaction [US Pat. No. 4,052,430],

In particular, since the Silane-based gas has a property of igniting at a low temperature, when these gases leak during the reaction, there is a problem in safety such as the risk of ignition.

In addition, the production yield (Yield) is low, there is a difficulty in controlling the molecular weight of the spinnable product.

On the other hand, if the PCS Green Fibers are manufactured by melt spinning at 200 oC using these PCSs and then thermally decomposed to produce SiC fibers,

Excess oxygen contained during stabilization of the PCS Green Fiber was decomposed at elevated temperatures, especially at elevated temperatures above 1,800 oC, making it impossible to obtain high density crystallized SiC fibers due to the coarse pores formed therein. [Patent Registration No. 10-0684649]

In addition, the oxygen content in the silicon carbide fiber is mixed by about 10% to form an oxycarbide amorphous in the form of SiCOx, which is thermally decomposed at a high temperature to cause a significant degradation of the physical properties of the fiber.

On the other hand, Nippon Carbon manufactures SiC fiber with oxygen content of 1% or less by stabilizing by using electron beam irradiation instead of thermal oxidation method to improve the heat resistance of SiC fiber, so that the tensile strength does not decrease even at high temperature of 1,500 oC. The super heat-resistant silicon carbide fiber was developed.

Therefore, the CVD method is very difficult to fabricate and manufacture a fiber having a diameter of 150 um or more, which is difficult to weave the fiber, and the precursor method has a high oxygen content in silicon carbide fibers, a low production yield, and an oxycarbide amorphous to form a high temperature. This causes a great decrease in the physical properties of the fiber.

On the other hand, in order to lower the oxygen content of silicon carbide fibers and improve the high temperature thermal stability, an additional electron beam stabilization process is required.

While these techniques suggest techniques related to the production of silicon carbide fibers, the present invention relates to other methods of manufacturing silicon carbide fibers.

On the other hand, as a technology related to a conventional ceramic heater or a heating element there is a patent registration No. 10-0413783 (registration date December 19, 2003) [ceramic heater for heating the sensor],

This patent relates to a ceramic heater for heating a sensor employing a composite electrode type heater electrode formed on a sensor heating heater substrate, which uses a high purity alumina powder and MgO additive of 99.999% or more to form a heater substrate. By manufacturing, it is excellent in durability at high temperature and high voltage, and a heater can be used for a long time without the short circuit of the heat generating material by the atomization phenomenon.

In addition, there is a patent registration No. 10-1406420 (registration date June 03, 2014) [silicon carbide heating element and its manufacturing method],

This patent discloses electrical resistance to a level suitable for heating element use by reacting and sintering a molding sprayed with silicon powder, and then volatilizing the remaining silicon, reacting with silicon which is not volatilized by doping with nitrogen, and completely removing silicon from the heating element. Since the silicon carbide heating element is doped with nitrogen in the silicon carbide lattice, there is a flow charge carrier, so it has a rapid temperature increase characteristic at low temperature, and the resistance increases as the temperature increases, thereby overheating itself. It suggests a technology that has the advantage of suppressing it.

In addition, there is a Patent Publication No. 10-2014-0007667 (published January 20, 2014) [ceramic heating element composition, dielectric heating device and dielectric heating method using the same],

This patent relates to a ceramic heating element composition, a dielectric heating device and a dielectric heating method using the same, in particular, a ceramic heating element that can reduce the occurrence of hot spots (hot spots) and increase the temperature increase rate and heat storage time A composition, a dielectric heating apparatus, and a dielectric heating method using the same.

However, these conventional technologies are basically related to a technique of mixing various ceramic materials and molding them by sintering, etc., and thus have a fundamental difference from the present invention of manufacturing a fibrous ceramic heating element by a gas infiltration reaction.

In addition, as interest in eco-friendly and high-efficiency energy increases, development of high-efficiency heaters using electricity is required.

In particular, high-efficiency heaters can be widely used throughout the industry, such as individual heating, industrial and agricultural dryers, industrial annealing furnaces, cooking cooking ovens.

In addition, as a power source for the heating device, it adopts an eco-friendly or high-efficiency method that utilizes solar, wind, and midnight electricity.

Related documents are disclosed in Korean Patent Nos. 10-0751485, 10-1998-032294 and 10-2003-0017179.

On the other hand, the literature related to a ceramic heating element containing silicon carbide is conventional patent registration No. 10-0413783 (registration date December 19, 2003) [Sensor heating ceramic heater],

This patent relates to a ceramic heater for heating a sensor employing a composite electrode type heater electrode formed on a sensor heating heater substrate, which uses a high purity alumina powder and MgO additive of 99.999% or more to form a heater substrate. By manufacturing, it is excellent in durability at high temperature and high voltage, and a heater can be used for a long time without the short circuit of the heat generating material by the atomization phenomenon.

In addition, there is a patent registration No. 10-1406420 (registration date June 03, 2014) [silicon carbide heating element and its manufacturing method],

This patent discloses electrical resistance to a level suitable for heating element use by reacting and sintering a molding sprayed with silicon powder, and then volatilizing the remaining silicon, reacting with silicon which is not volatilized by doping with nitrogen, and completely removing silicon from the heating element. Since the silicon carbide heating element is doped with nitrogen in the silicon carbide lattice, there is a flow charge carrier, so it has a rapid temperature increase characteristic at low temperature, and the resistance increases as the temperature increases, thereby overheating itself. It suggests a technology that has the advantage of suppressing it.

In addition, there is a Patent Publication No. 10-2014-0007667 (published January 20, 2014) [ceramic heating element composition, dielectric heating device and dielectric heating method using the same],

The present patent relates to a ceramic heating element composition, a dielectric heating apparatus and a dielectric heating method using the same, in particular, the ceramic heating element composition, dielectric that can reduce the occurrence of hot spots and increase the temperature increase rate and heat storage time A heating heater and a dielectric heating method using the same.

Furthermore, there is a patent registration No. 10-1288342 (registration date July 16, 2013) [the manufacturing method of porous silicon carbide heating element],

This patent discloses a method of manufacturing a porous silicon carbide heating element that is excellent in infrared radiation efficiency, high temperature stability and durability, and can be applied economically and easily to a radiator heater.

In the formation of heating elements such as a radiator heater, porous silicon carbide having excellent thermal efficiency is used by using a porous polymer foam that is easy to process and cut without directly processing a silicon carbide material having high hardness, which is difficult to process such as cutting or polishing. The heating element can be manufactured easily and economically in an optimized form. The porous silicon carbide heating element manufactured according to the present invention has a pore structure, which enables instant heating by flame when burning fuel gas, induces complete combustion of fuel gas, and prevents backfire of flame in pores. Combustion takes place, resulting in very good thermal efficiency.

However, these conventional technologies are basically a technique of mixing a variety of ceramic materials to form a bulk form in the form of sintering, etc. and the heat generated by the electrical resistance, this type of electric heater consumes excessive power, heating compared to the heat to be heated It took a long time and had the disadvantage of low efficiency.

Above all, these prior arts are related to a technique of mixing various ceramic materials and molding them by sintering or the like, which is also fundamentally different from the present invention in which a fibrous ceramic heating element is manufactured by gas infiltration reaction.

On the other hand, recently, many methods of heating using electricity such as electric resistance method or microwave method have been developed, and heating methods using solar heat, wind power, midnight electricity, etc. as electric supply methods are mostly registered with these technologies. 10-0751485, 10-1998-032294 and 10-2003-0017179, and the like are disclosed.

As a heating element of the heating method using electricity, metal heating elements have been mainly used, and inexpensive nichrome wire, iron chromium wire, and cantal wire (Fe-Cr-Al) are used as the metal heating material, but power consumption is high. Due to its high and brittleness due to heat, its structural stability is weak at high temperatures.

Meanwhile, as a heating element used for heating an industrial furnace, a thick ceramic heating element that is relatively stable at high temperature is widely used. Ceramic heating elements made of molybdenum disilicide (MoSi2) or silicon carbide (SiC) are used as industrial heating elements. However, when used as household heating devices, the inrush current is very high under the household line voltage (110V or 220V). There are disadvantages. Since a heating element having a large inrush current is not suitable for home appliances, conventional ceramic heating elements have been required to use expensive transformers that drop voltage from line voltage.

If the conventional thick ceramic heating element is to directly use the commercial power (110V or 220V) as a home heating device, it is necessary to increase the length or reduce the cross-sectional area based on the basic resistance formula below.

R = ρ * L / A, (ρ: resistivity, L: length, A: cross-sectional area)

However, this method creates a fatal problem of reduced mechanical strength in its application due to its increased length and reduced cross-sectional area. In addition, these types of heating elements have a disadvantage of low efficiency due to a long heating time compared to heat to be heated.

In order to solve the above problems of the prior art, the present invention, in a simpler method, the ceramic heating element is stripped from various ceramic powder molding methods such as sintering, and the silicon carbide fibers and the metal doped carbonization by a gas infiltration reaction. It is an object of the present invention to provide a method for directly producing silicon fibers, and to provide applications such as silicon carbide fibers and fibrous ceramic heating elements using the same, and further, heating devices.

Specifically, the present invention relates to a method of manufacturing a fibrous ceramic heating element by a gas infiltration reaction sublimated at a high temperature, in particular, a method of manufacturing a fibrous ceramic heating element through a process of directly manufacturing silicon carbide fibers from carbon fibers and thereby It is an object to provide an application such as a heating element.

In addition, an object of the present invention is to provide a method for producing a low-oxygen, dense crystalline silicon carbide fibers in order to improve the high temperature thermal stability of the silicon carbide fibers to provide a method for producing a fibrous ceramic heating element and thereby a heating element.

In addition, the present invention is to produce a nano-doped silicon carbide fiber including a doping source in the gas permeation reaction in order to improve the oxidation resistance, heat resistance and the like of the silicon carbide fiber, and a method for producing a fibrous ceramic heating element using the same It is an object to provide an application such as a heating element.

Furthermore, an object of the present invention is to provide a silicon carbide fiber having a diameter of 5 to 100 um from the gas permeation reaction, a method of manufacturing a fibrous ceramic heating element using the same, and a heating element thereby.

Furthermore, an object of the present invention is to provide a method for producing silicon carbide fibers including a batch or continuous process, a method for producing a fibrous ceramic heating element using the same, and a heating element by the process of directly converting the silicon carbide fibers.

On the other hand, the present invention is a fibrous ceramic heating element produced by the gas infiltration reaction (Gas Infiltration Reaction), in addition to silicon carbide fibers (SiCf), glass, alumina, silica, Si3N4, silicate, boron, SiCO, Si-CNO It is an object to provide a silicon carbide fiber, a manufacturing method, a method for producing a fibrous ceramic heating element thereof, and a heating element thereby, which may be a fiber and manufacture these nano-doped fibers.

In particular, the present invention provides a structure in which a carbon fiber having a predetermined diameter (hereinafter referred to as a 'core carbon fiber') remains in the center (core) portion, and the silicon carbide fiber described above wraps the core carbon fiber in a predetermined thickness on an outer circumferential surface thereof. It aims to do it.

In addition, the present invention is a high efficiency that can generate heat through the resonance within the fiber is absorbed by silicon carbide fibers generated from the magnetron or heat generated by the electrical resistance method, particularly rapid heat generation and can minimize the loss of thermal energy An object of the present invention is to provide a silicon carbide fiber heating element and a heating device using the same.

On the other hand, the present invention is to solve the problems as described above, and to directly produce the silicon carbide fibers and nano-doped silicon carbide fibers by the gas infiltration reaction (Gas Infiltration Reaction) by removing from the heating device or the heating element heating device. And a heater, heating device or the like, having an average diameter of 50 um or less, preferably 50 um or less, more preferably 10 um or less, in which the silicon carbide fiber heating element and the electric resistance or the wavelength of the microwave generated in the magnetron generate heat. It is an object to provide a heat generating device.

Specifically, an object of the present invention is to provide a heat generating apparatus including a heat conductor which is in contact with a silicon carbide fiber heating element and may be a conduit through which a fluid such as heating water flows, and has a power source for stimulating silicon carbide fiber heating element to generate heat. .

It is another object of the present invention to provide a heat generating device having a configuration in which the power supply unit includes a magnetron for generating microwaves for resonance and heat generation of a silicon carbide fiber heating element.

In order to achieve the above object, the method for producing silicon carbide fibers and the silicon carbide fibers thereby

Sublimation raw material and carbon fiber selected from silicon or silicon dioxide, or mixtures thereof are placed in a vacuum or inert gas atmosphere and at a high temperature so that sublimation of the sublimation raw material is carried out from the carbon carbide from the carbon carbide by gas infiltration reaction. By making fibers.

In addition, the method for producing silicon carbide fibers according to the present invention and the silicon carbide fibers thereby

Sublimation raw materials and fibrous materials are placed in a vacuum or inert gas atmosphere and at a high temperature, and then the glass, alumina, silica, Si3N4, silicate, boron, It is made of SiCO, Si-CNO fiber and used as heating element.

The method for producing silicon carbide fibers according to the present invention and the silicon carbide fibers thereby

The nano-doped silicon carbide fibers are prepared by placing the doping source together with the carbon fibers at a higher temperature.

In particular the metal is selected from the group consisting of titanium, aluminum, zirconium, molybdenum, boron, halogen, or combinations thereof,

Gas permeation reaction temperature is made by heating to 1,000 ~ 2,000 oC at a temperature increase rate of 5 ~ 20 oC / min,

It is preferred to proceed with a batch or continuous process.

Furthermore, in the silicon carbide fiber according to the present invention, a manufacturing method thereof, a heating element using the same, in other applications

Si / C element content of the prepared silicon carbide fiber is 0.01 ~ 2.0,

Oxygen content of the manufactured silicon carbide fiber is less than 2.0%,

Carbon fiber refers to carbon fiber made of a precursor of a fiber such as polyacrylonitrile, pitch or rayon,

It is preferable that the monofilament diameter of this carbon silicon fiber is 5-100um.

On the other hand, the silicon carbide fiber heating element according to the present invention in order to achieve the above object

Any sublimation raw material and carbon fiber selected from silicon or silicon dioxide, or mixtures thereof are placed in a vacuum or inert gas atmosphere and a high temperature state,

It is made from carbon fiber by gas infiltration reaction by sublimation of sublimation raw materials,

Heat is generated by applying a microwave, or heat generated by the electrical resistance method.

Furthermore, the heating device using the silicon carbide fiber heating element

And a magnetron for generating microwaves for resonance and heat generation of the silicon carbide fiber heating element.

In addition, the heating device using the silicon carbide fiber heating element according to the present invention

Silicon carbide fiber heating element;

A heat conductor in contact with the silicon carbide fiber heating element; And

A power supply unit for generating heat by stimulating the silicon carbide fiber heating element;

It is made, including.

In addition, the heating device using the silicon carbide fiber heating element according to the present invention

 Silicon carbide fiber heating element;

A power supply unit for generating heat by stimulating the silicon carbide fiber heating element;

It is made, including.

In the heat generator using the silicon carbide fiber heating element according to the present invention

The heat conductor is a pipeline through which a fluid flows,

The power supply unit preferably includes a magnetron for generating microwaves for resonance and heat generation of the silicon carbide fiber heating element.

According to the present invention, the carbon fiber is directly converted into silicon carbide fiber by sublimation gas permeation reaction at high temperature (other glass, alumina, silica, Si3N4, silicate, boron, SiCO, Si-CNO fibers are also available). Not only this simple but also the heating element can be continuously produced, it is possible to produce crystalline silicon carbide fibers with excellent physical properties by controlling the reaction conditions, in particular, to produce doped source doped silicon carbide fibers with improved oxidation resistance, heat resistance, etc. It has excellent heat resistance, corrosion resistance and electrical characteristics, so it can be used in high-tech electrical, electronic, chemical, physics and other industrial fields,

In particular, it is possible to provide a heating element that can be utilized in a furnace, a power plant, an industrial / agricultural drying furnace, a household heating device or a cooking heating device (hot plate, electric range, etc.) and various heating devices using the same.

In addition, the silicon carbide fiber heating element and the heating device using the same according to the present invention, the wavelength of the microwave generated from the magnetron is absorbed by the silicon carbide fiber and can be rapidly generated within a short time through the resonance in the fiber or through the electrical resistance method In addition, the loss of thermal energy can be minimized to provide high efficiency characteristics.

Furthermore, the heating device according to the present invention uses a rapid heating highly efficient silicon carbide fiber heating element, thereby providing a rapid heating characteristic that can be minimized with loss of thermal energy.

High-efficiency silicon carbide fiber heating element that can be applied to various heating elements regardless of the shape of various heaters or heaters, and can be heated while minimizing the loss of thermal energy by allowing heat to be rapidly generated and heated in a short time. It is possible to provide a heating device using.

1 is a schematic diagram showing a process of forming a silicon carbide layer from the surface of the carbon fiber by the gas permeation reaction by the method for producing a silicon carbide fiber heating element according to the present invention.

2 is an enlarged photograph of a silicon carbide fiber heating element generated by microwaves.

3 is a conceptual diagram of a heating device having a magnetron according to the present invention.

Figure 4 is a schematic diagram of a heating device using a silicon carbide fiber heating element according to the present invention.

* Description of the symbols for the main parts of the drawings *

100: heating device 110: casing

111: pipeline 112: insulation

114: heating element

The objects, features, and advantages of the present invention described above will become more apparent through the following embodiments in conjunction with the accompanying drawings.

The following specific structures or functional descriptions are merely illustrated for the purpose of describing embodiments in accordance with the inventive concept, and embodiments according to the inventive concept may be embodied in various forms and may be described in detail herein. It should not be construed as limited to the examples.

Embodiments in accordance with the concepts of the present invention can be variously modified and have a variety of forms, specific embodiments will be illustrated in the drawings and described in detail herein. However, this is not intended to limit the embodiments in accordance with the concept of the present invention to a particular disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and / or second may be used to describe various components, but the components are not limited to the terms. The terms are only for the purpose of distinguishing one component from other components, for example, without departing from the scope of the rights according to the inventive concept, the first component may be called a second component, and For example, the second component may also be referred to as a first component.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected or connected to that other component, but it may be understood that other components may be present in the middle. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that no other component exists in the middle. Other expressions to describe the relationship between components, such as "between" and "immediately between" or "adjacent to" and "directly adjacent to", should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. The terms "comprise" or "having" herein are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof that is practiced, and that one or more other features or numbers, It is to be understood that it does not exclude in advance the possibility of the presence or addition of steps, actions, components, parts or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and are not construed in ideal or excessively formal meanings unless expressly defined herein. Do not.

The method for producing silicon carbide fibers according to the present invention and the silicon carbide fibers thereby

Sublimation of any sublimation raw material selected from silicon or silicon dioxide, or a mixture thereof is made from carbon fibers disposed together by a sublimated gas infiltration reaction. .

This gas permeation reaction is preferably carried out in a vacuum or inert gas atmosphere.

In addition, the silicon carbide fiber, the heating element and the heating device using the same according to the present invention to further arrange a doping source to produce a silicon carbide fiber doped with the doping source to the physical properties such as oxidation resistance and heat resistance It is desirable to produce improved silicon carbide fibers and heating elements thereof.

In particular, the doping source is preferably selected from the group consisting of titanium, aluminum, zirconium, molybdenum, boron, halogen or combinations thereof. These doped source particles may be disposed on the SiC surface or may be disposed in the SiC particles.

Furthermore, the method for producing the silicon carbide fiber and the heating element according to the present invention is a step of converting the silicon carbide fiber directly into a batch or continuous process.

On the other hand, the silicon carbide fiber and its heating element are manufactured from carbon fibers (Silicon Carbide Fibers, SiCf) in addition to glass, alumina, silica, Si3N4, silicate, boron (Boron Nitride , BNf), etc.), SiCO, Si-CNO fibers, and also a doping source is further arranged to provide these ceramic fibers doped with doping source particles (elements, etc.).

On the other hand, the gas permeation reaction temperature is preferably made by heating to 1,000 ~ 2,000 oC at a temperature increase rate of 5 ~ 20 oC / min.

In the present invention, the carbon fiber as the base material means a carbon fiber made of a precursor of a fiber such as polyacrylonitrile, pitch or rayon, and the diameter of the carbon fiber is preferably 5 to 100 um.

Silicon carbide fibers and the heating element according to the production method according to the invention is preferably Si / C element content of 0.01 ~ 2.0, the oxygen content of silicon carbide fibers is preferably 2.0% or less.

In particular, the silicon carbide fiber and the heating element of the present invention is preferably used as a heating element, silicon carbide fiber consisting of components such as Si-C, Si-OC, Si-CNO and silicon carbide fibers having a monofilament diameter of 5 to 100 um. Do.

In addition, the silicon carbide fiber heating element of the present invention may be utilized by processing into various shapes such as mesh, plate, rod and the like through secondary processing such as weaving or lamination to apply to various heating devices such as industrial, agricultural, and household.

[Production Example 1]

Sublimation raw material and carbon fiber selected from silicon or silicon dioxide, or mixtures thereof are placed in a batch electric furnace equipped with alumina tube, and then carbonized by heating to 1,000 to 2,000 oC at a temperature of 10 oC / min at a temperature of 10 oC / min under nitrogen or argon gas atmosphere. A silicon carbide fiber heating element that can be used as a silicon fiber heating element was prepared.

By controlling the diffusion reaction time of the sublimation gas at the predetermined temperature to produce a silicon carbide fiber and its application, that is, a heating element.

[Production Example 2]

After placing a sublimation raw material selected from silicon or silicon dioxide or a mixture thereof in a continuous electric furnace equipped with alumina tubes, the carbon fibers are placed in an alumina tube.

After maintaining a sublimation temperature of 1,000 to 2,000 oC at a temperature of 10 oC / min in a nitrogen or argon gas atmosphere

The winding speed of the fiber winding machine is set to the desired level according to the desired production speed, thereby producing silicon carbide fibers which can be used as a silicon carbide fiber heating element continuously.

[Examples 1-3]

After maintaining a sublimation temperature of 1,750 oC from Preparation Example 1, the diffusion reaction time was varied by 30 minutes (Example 1), 60 minutes (Example 2), 120 minutes (Example 3).

[Examples 4 to 8]

0.1 wt% titanium (Example 4), aluminum 0.1 wt% (Example 5), zirconium 0.1 wt% (Example 6), molybdenum 0.1 wt% (Example 7), 0.1 wt% of boron in the sublimation raw material from Preparation Example 1 % (Example 8) was further mixed with each other to sublimate for 120 minutes at a sublimation temperature of 1750 oC to perform the diffusion reaction of the sublimation gas and carbon fiber, which can be used as a silicon carbide fiber heating element, doped silicon carbide fibers doped with a doping source And the heating element was manufactured.

Example 9

From the preparation example 2, the silicon carbide fiber which can be used as a silicon carbide fiber heating element was continuously manufactured at a sublimation temperature of 1,750 ° C. under a nitrogen or argon gas atmosphere at a speed of 3 cm / min.

Table 1

As shown in Table 1 and the accompanying FIG. 1 (FIG. 1 is a schematic diagram showing a silicon carbide layer formed from a carbon fiber surface by a sublimation gas infiltration reaction and a SEM analysis photograph of silicon carbide fibers at a specific time period. have),

It can be seen that as the reaction time increases, the silicon carbide layer is increased to finally convert to silicon carbide fibers.

In the present invention, the diameter of the carbon fiber (core shell) is preferably 1 to 3㎛.

Experimental Example 1

A silicon carbide fiber doped with a doping source (Ti) according to Example 4 was prepared and used as a silicon carbide fiber heating element, and an exothermic experiment was performed with a heating element in a heating device equipped with a magnetron.

As a result, as shown in the enlarged photograph of FIG. 2, the reticulated silicon carbide fiber heating element (L 150mm × W 150mm × H 5mm) generates heat even at low power of 300W or less, and in particular, generates heat at a high temperature of 1,000 ° C. or more within 4 seconds. It was confirmed that.

Furthermore, the heating device according to the present invention preferably comprises a silicon carbide fiber heating element manufactured through the sublimation gas penetration reaction, and a magnetron for generating microwaves for resonance and heat generation of the heating element.

Alternatively, the heating device using the silicon carbide fiber heating element according to the present invention may be composed of an electric resistance type heating device including a power supply unit for stimulating the silicon carbide fiber heating element to generate heat (silicon carbide fiber heating element of a unit volume). In the case of heating by electric resistance method by adding power consumption of 17w, 35V, 0.49A, rapid heating to 1,000 ° C or more within 2 seconds, showing faster cooling behavior than the conventional heating element).

The silicon carbide fiber heating element rapidly generates heat within a short time of 2 to 5 seconds through wavelength absorption and resonance of the microwave generated from the magnetron, and due to the characteristics of the fiber, it is possible to minimize the loss of thermal energy, thereby achieving high efficiency characteristics. It can be secured.

In addition, as can be seen in the conceptual diagram of Figure 3, in the heating device of the present invention through the drive switching and variable output control of the magnetron generating microwaves to control the exothermic temperature of the silicon carbide fiber heating element within the range of 300 oC ~ 1,400 oC Can be. In FIG. 3, it is possible to check the exothermic picture of the silicon carbide fiber heating element in a reticulated secondary processing state heated by microwaves in the magnetron heating device.

On the other hand, the heating device which forms the core of the present invention is a silicon carbide fiber heating element,

A heat conductor in contact with the silicon carbide fiber heating element,

It comprises a power supply for stimulating the silicon carbide fiber heating element to generate heat.

The heat conductor may be a metal panel, and the heating device may be a cooking utensil, a heating device, a dryer, or the like.

In addition, the power supply unit may include a magnetron for generating a microwave for the resonance and heat generation of the silicon carbide fiber heating element, the silicon carbide fiber heating element may take the form of electric resistance heating if necessary.

Furthermore, in the heating device according to the present invention, the power supply unit may include a magnetron for generating microwaves for resonance and heat generation of the silicon carbide fiber heating element.

The silicon carbide fiber heating element is preferably a silicon carbide fiber heating element manufactured through the sublimation gas penetration reaction described above.

Specifically, referring to FIG. 4, there is shown a conceptual diagram of a kind of hot air blower or boiler 100 showing a form in which the heat conductor is a conduit 111 through which a fluid flows.

The heat generating device 100 is provided with a silicon carbide fiber heating element 114 and a conduit 111 which is a heat conductor in contact with the casing 110.

Fluid flows through the conduit 111, and when the fluid is air supplied by a blower (not shown), the heat generating device is configured as a hot air blower, and the fluid is supplied by the circulation pump (not shown). In the case of the heating device constitutes a boiler 100 that is a heating device.

In addition, the pipe 111 is preferably surrounded by a heat insulating material 112 to prevent heat loss, it is preferable to use a material having excellent thermal conductivity, such as copper.

The heat insulating material 112 is preferably a non-combustible material that can be used even at a high temperature (1300 ℃ or more) heating temperature.

The power supply unit for stimulating and heating the silicon carbide fiber heating element 114 generates a microwave, and a waveguide for guiding the microwaves generated from the magnetron 120 to the silicon carbide fiber heating element 114. 130).

In addition, if necessary, a relay body 113 is further provided between the heat insulator 112 and the heating element 114 to be used as an additional waveguide member, and the microwave generated from the magnetron 120 is a waveguide 130 and a relay body ( It is guided to the silicon carbide fiber heating element 114 through 113, the relay body may utilize a ceramic material.

On the other hand, the casing 120 preferably employs a material (eg, SUS) for preventing microwaves from being released to the outside and protecting internal components from external shocks.

In the heating device according to the present invention, the microwave generated from the magnetron is transferred to the silicon carbide fiber heating element through the heat insulating material and the relay (ceramic) inside the casing via the waveguide, and the silicon carbide fiber is finally delivered to the wavelength of the microwave. The silicon carbide fibers generated by resonance and heat generation can heat the heating water passing through the adjacent pipe line by the heat rapidly increasing between 1 to 5 seconds.

Although FIG. 4 describes that the silicon carbide fiber heating element is disposed only in the lower part of the conduit, the silicon carbide fiber heating element may be configured to surround the conduit.

Claims (10)

1. Sublimation raw material and carbon fiber selected from silicon or silicon dioxide, or mixtures thereof are placed in a vacuum or inert gas atmosphere and at a high temperature so that sublimation of the sublimation raw material is carried out from the carbon carbide from the carbon carbide by gas infiltration reaction. Method for producing silicon carbide fibers to produce fibers.
2. The method of claim 1,

   A method for producing silicon carbide fibers, characterized in that the doping source is placed at a higher temperature together with the carbon fibers to be nano-doped.
3. The method of claim 2,

   The doping source is a method of producing silicon carbide fibers, characterized in that selected from the group consisting of titanium, aluminum, zirconium, molybdenum, boron, halogen or a combination thereof.
4. The method according to any one of claims 1 to 3,

   Gas permeation reaction temperature is made by heating to 1,000 ~ 2,000 oC at a temperature increase rate of 5 ~ 20 oC / min,

   Process for producing silicon carbide fibers, characterized in that the batch or continuous process.
5. Any sublimation raw material and carbon fiber selected from silicon or silicon dioxide, or mixtures thereof are placed in a vacuum or inert gas atmosphere and a high temperature state,

   It is made of silicon carbide fiber from carbon fiber by gas infiltration reaction by sublimation of sublimation raw material,

   A method of producing a fibrous ceramic heating element used as a heating element comprising carbon fibers and silicon carbide fibers.
6. Any sublimation raw material and carbon fiber selected from silicon or silicon dioxide, or mixtures thereof are placed in a vacuum or inert gas atmosphere and a high temperature state,

   It is made from carbon fiber by gas infiltration reaction by sublimation of sublimation raw materials,

   Silicon carbide fiber heating element that generates heat by applying microwave.
7. The silicon carbide fiber heating element of claim 6,

   A heating device comprising a magnetron for generating microwaves for resonance and heat generation of this heating element.
8. The silicon carbide fiber heating element of claim 5;

   A heat conductor in contact with the silicon carbide fiber heating element; And

   A power supply unit for generating heat by stimulating the silicon carbide fiber heating element;

   Heating device comprising a.
9. The method of claim 8,

   The heat conductor is a heating device, characterized in that the fluid flow through the pipe.
10. The silicon carbide fiber heating element of claim 5;

    A power supply unit for generating heat by stimulating the silicon carbide fiber heating element;

    Heating device comprising a.

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