KR100299099B1 - Manufacturing Method of Silicon Carbide Ceramic Seals by Liquid Phase Reaction Sintering - Google Patents
Manufacturing Method of Silicon Carbide Ceramic Seals by Liquid Phase Reaction Sintering Download PDFInfo
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- KR100299099B1 KR100299099B1 KR1019990015659A KR19990015659A KR100299099B1 KR 100299099 B1 KR100299099 B1 KR 100299099B1 KR 1019990015659 A KR1019990015659 A KR 1019990015659A KR 19990015659 A KR19990015659 A KR 19990015659A KR 100299099 B1 KR100299099 B1 KR 100299099B1
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- silicon carbide
- sintering
- liquid phase
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- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 52
- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 47
- 238000005245 sintering Methods 0.000 title claims abstract description 44
- 239000000919 ceramic Substances 0.000 title claims abstract description 35
- 238000006243 chemical reaction Methods 0.000 title claims abstract description 25
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 16
- 239000007791 liquid phase Substances 0.000 title claims abstract description 14
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 52
- 239000003566 sealing material Substances 0.000 claims abstract description 17
- 239000011230 binding agent Substances 0.000 claims abstract description 13
- 239000000203 mixture Substances 0.000 claims abstract description 11
- 239000000565 sealant Substances 0.000 claims abstract description 10
- 239000002994 raw material Substances 0.000 claims description 25
- 229910052710 silicon Inorganic materials 0.000 claims description 24
- 239000010703 silicon Substances 0.000 claims description 24
- 229910002804 graphite Inorganic materials 0.000 claims description 17
- 239000010439 graphite Substances 0.000 claims description 17
- 239000006229 carbon black Substances 0.000 claims description 12
- 239000002184 metal Substances 0.000 claims description 12
- 229910052751 metal Inorganic materials 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 12
- 238000002156 mixing Methods 0.000 claims description 8
- 238000010304 firing Methods 0.000 claims description 4
- 239000010419 fine particle Substances 0.000 claims description 2
- 238000005538 encapsulation Methods 0.000 claims 1
- 239000011361 granulated particle Substances 0.000 claims 1
- 229910052799 carbon Inorganic materials 0.000 abstract description 24
- 239000011148 porous material Substances 0.000 abstract description 12
- 238000000465 moulding Methods 0.000 abstract description 9
- 239000000126 substance Substances 0.000 abstract description 4
- 238000010438 heat treatment Methods 0.000 abstract description 3
- 230000007547 defect Effects 0.000 abstract description 2
- 230000015572 biosynthetic process Effects 0.000 abstract 1
- 239000011541 reaction mixture Substances 0.000 abstract 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 27
- 239000000843 powder Substances 0.000 description 16
- 239000002245 particle Substances 0.000 description 10
- 230000007797 corrosion Effects 0.000 description 8
- 238000005260 corrosion Methods 0.000 description 8
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 4
- 229910021431 alpha silicon carbide Inorganic materials 0.000 description 4
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 4
- 230000001965 increasing effect Effects 0.000 description 4
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 3
- 238000005452 bending Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 229910052582 BN Inorganic materials 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 2
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000000280 densification Methods 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 238000005469 granulation Methods 0.000 description 2
- 230000003179 granulation Effects 0.000 description 2
- 238000007731 hot pressing Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000003826 uniaxial pressing Methods 0.000 description 2
- 229910016006 MoSi Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229920006184 cellulose methylcellulose Polymers 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000008393 encapsulating agent Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 238000001513 hot isostatic pressing Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 238000013001 point bending Methods 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- HNJBEVLQSNELDL-UHFFFAOYSA-N pyrrolidin-2-one Chemical compound O=C1CCCN1 HNJBEVLQSNELDL-UHFFFAOYSA-N 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000011863 silicon-based powder Substances 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/64—Burning or sintering processes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B1/00—Producing shaped prefabricated articles from the material
- B28B1/26—Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor
- B28B1/265—Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor pressure being applied on the slip in the filled mould or on the moulded article in the mould, e.g. pneumatically, by compressing slip in a closed mould
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/56—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
- C04B35/565—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide
- C04B35/573—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide obtained by reaction sintering or recrystallisation
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
- C04B35/632—Organic additives
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/42—Non metallic elements added as constituents or additives, e.g. sulfur, phosphor, selenium or tellurium
- C04B2235/422—Carbon
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
- C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
Abstract
본 발명은 액상 반응소결(Liquid Phase Reaction Sintering)법과 탄화규소 (SiC) 세라믹스를 이용하여 화학 펌프, 마그네틱 펌프 및 송풍기에 사용하는 세라믹 밀봉재(Ceramics Seal)의 제조방법에 관한 것이다.The present invention relates to a method for producing ceramic seals for use in chemical pumps, magnetic pumps, and blowers using liquid phase reaction sintering and silicon carbide (SiC) ceramics.
본 발명은 95∼85 중량의 탄화규소에 5∼15 중량의 탄소를 기본 조성으로 하여 유기바인더를 성형보조제로 첨가하고 이들을 혼합하여 실온에서 800℃까지 1∼2℃/분의 느린 속도로 승온시켜 성형체에 결함이 생성시키지 않도록 하고 바인더를 제거하기 위하여 열처리한 후, 1,600∼1,700℃의 온도범위에서 0.5∼1시간 동안 반응소결하여 탄화규소 세라믹 밀봉재를 제조한다.The present invention adds an organic binder as a molding aid with 5 to 15 weights of carbon as a basic composition to 95 to 85 weights of silicon carbide, and mix and mix them to a temperature of 1 to 2 ℃ / min from room temperature to 800 ℃ After the heat treatment to prevent the formation of defects in the molded body and to remove the binder, the reaction mixture is sintered at a temperature range of 1,600 to 1,700 ° C for 0.5 to 1 hour to produce a silicon carbide ceramic sealing material.
본 발명은 기공이 없이 치밀하며, C-ring 강도 400 MPa 이상, 경도 2,000 kg/mm2이상을 갖는 탄화규소 세라믹 밀봉재 소결체의 제조하는 것을 목적으로 한다.An object of the present invention is to produce a silicon carbide ceramic sealant sintered compact having no pores and having a C-ring strength of 400 MPa or more and a hardness of 2,000 kg / mm 2 or more.
Description
본 발명은 액상 반응소결(Liquid Phase Reaction Sintering)법과 탄화규소 (SiC) 세라믹스를 이용하여 화학 펌프, 마그네틱 펌프 및 송풍기에 사용하는 세라믹 밀봉재(Ceramics Seal)의 제조방법에 관한 것이다.The present invention relates to a method for producing ceramic seals for use in chemical pumps, magnetic pumps, and blowers using liquid phase reaction sintering and silicon carbide (SiC) ceramics.
종래에 섬유공업, 화학공업의 케미컬 펌프, 전자산업의 마그네틱 펌프에는 밀봉재 부품으로 고분자 재료, 금속 및 내열합금 재료를 주로 사용하였으나, 이들 부품은 고온이나 내식, 내마모성 분위기에서는 사용이 제한적이며, 제품의 내구성이 짧아 빈번한 수리나 교체로 인해 공정상의 품질제어가 어려울 뿐만 아니라, 원가상승의 요인이 되고 있다. 그에 따라 내열성, 내마모성 및 내식성이 우수한 재료를 이용한 밀봉재 대체의 필요성이 증대되고 있다.Conventionally, polymer materials, metals, and heat-resistant alloy materials are mainly used for the chemical pumps of the textile industry, the chemical industry, and the magnetic pumps of the electronics industry. However, these parts are limited in high temperature, corrosion resistance, and wear resistance atmosphere. Due to its short durability, it is difficult to control the quality of the process due to frequent repairs or replacements, and it is a factor of cost increase. Accordingly, the necessity of replacing the sealing material using a material having excellent heat resistance, abrasion resistance and corrosion resistance is increasing.
세라믹스는 고강도, 고경도 및 내마모성 등의 기계적 특성과 함께 우수한 내산화성, 내부식성, 낮은 열전도성 및 열팽창계수에 의한 높은 내열충격성, 고온강도 등의 열적 특성을 보유하고 있으므로 선진국에서는 이들을 이용한 소재개발 연구 및 상용화에 박차를 가하고 있다. 세라믹스 중에서 탄화규소는 재료의 특성상 강한 공유결합(covalent bonding)을 이루고 있어 소결성이 낮기 때문에 금속재료와 같이 이론밀도에 달하는 치밀화를 위해서는 2,000℃ 이상의 높은 온도와 특정한 소성기술을 필요로 하는데, 이러한 소결방법으로는 현재 상압소결(Pressureless Sinteing), 열간가압소결(Hot Pressing), 열간등가압소결(Hot Isostatic Pressing)및 액상 반응소결(Reaction Sintering)과 같은 다양한 소결방법이 개발되어 있다.Ceramics have thermal properties such as high oxidation resistance, corrosion resistance, low thermal conductivity and high thermal shock and high temperature strength due to mechanical properties such as high strength, high hardness and abrasion resistance. And spurring commercialization. Among the ceramics, silicon carbide has strong covalent bonding due to the characteristics of the material, and thus has low sintering property. Therefore, for densification reaching a theoretical density like a metal material, a high temperature of 2,000 ° C. or higher and a specific firing technique are required. Various sintering methods such as Pressureless Sinteing, Hot Pressing, Hot Isostatic Pressing, and Reaction Sintering have been developed.
이들 소결방법은 서로 장단점을 갖고 있는데 상압소결, 열간가압소결법이나 열간등가압소결법을 이용한 세라믹 재료의 치밀화 경우에는 기계적, 열적 특성이 액상 반응소결법에 비해 다소 높은 소결체를 제조할 수 있는 장점이 있는 반면 고가의 소성장비를 사용해야 하고 제조공정상 고가인 미분(fine powder)의 원료 및 소결조제(sintering aids)를 사용해야 한다. 또한 소성온도가 1,800℃ 이상으로 매우 높아 에너지 비용의 상승으로 인한 제품단가가 높아질 뿐만 아니라, 소결 후 수축으로 인해 복잡한 형상의 제품을 소결하기에 어려운 단점이 있어 상용화 및 양산화에 한계가 있다.These sintering methods have advantages and disadvantages.In the case of densification of ceramic materials using atmospheric pressure sintering, hot pressing sintering or hot isostatic sintering, the mechanical and thermal characteristics of the sintered body are higher than those of liquid phase sintering. Expensive firing equipment should be used and expensive fine powder raw materials and sintering aids should be used in the manufacturing process. In addition, since the firing temperature is very high, more than 1,800 ℃, not only the product cost is increased due to the increase in energy costs, but also difficult to sinter a complex shape product due to shrinkage after sintering, there is a limitation in commercialization and mass production.
이에 비해 액상 반응소결법은 미분의 원료 및 고가의 소결조제를 첨가하지 않고, 상기에서 언급한 소결법에 비하여 낮은 온도(1,500∼1,700℃)에서 소결이 가능할 뿐만 아니라, 소결반응이 매우 빠르게 진행되고, 소결시 수축이나 팽창 등의 치수변화가 거의 없어 정밀치수, 복잡한 형상, 대형의 제품을 쉽게 소결할 수 있는 장점이 있어 생산성 향상과 함께 에너지 비용을 절감할 수 있다.In contrast, the liquid phase sintering method does not add finely divided raw materials and expensive sintering aids, and it is possible to sinter at a low temperature (1,500 to 1,700 ° C) as compared to the sintering method mentioned above, and the sintering reaction proceeds very quickly, and There is almost no dimensional change such as shrinkage or expansion at the time, so it has the advantage of easy sintering of precision dimension, complex shape and large sized product, which can improve productivity and reduce energy cost.
한편 본 발명과 관련된 종래의 기술로서 특허는 특허 제94-073325호로 공개된(1994년 01월 28일) '탄화규소질 세라믹 전열관 소결체의 제조방법' 등의 내용이 있으며, 논문으로는 당 연구소에서 한 인섭, 우 상국 등이 한국요업학회지에 발표한 '부식성 분위기하에서 세라믹스 내식 특성-반응소결 탄화규소 내식특성-(Vol.27, No.2, pp.161∼168, 1990)', '흑연 첨가량에 따른 반응소결 탄화규소의특성(Vol.30, No.1, pp.69∼77, 1993)', '반응소결에 의한 SiC/MoSi2복합체의 특성(Vol.31, No.4, pp.399∼406, 1994)', '반응결합 소결법을 이용한 SiC 복합체 제조(Vol.31, No.5, pp.561∼571, 1994)', '반응결합 소결에 의한 SiC-TiC계 복합재료 제조(Vol.31, No.8, pp.849∼860, 1994)' 등 다수의 논문이 있다. 그러나 상기 특허의 경우는 그 내용이 세라믹 열교환기 제조를 위한 탄화규소질 세라믹 전열관 소결체의 제조방법에 관한 것이며, 논문의 경우에는 반응소결법에 의한 SiC 복합체의 제조 및 특성평가에 관한 내용으로서 본 발명과는 원료조성 및 성형방법, 소결방법 면에서 차이가 있다.On the other hand, as a conventional technology related to the present invention, the patent is published in the patent 94-073325 (January 28, 1994), 'the manufacturing method of silicon carbide ceramic heat pipe sintered body', etc. Han In-Seop, Woo Sang-guk, etc., published in the Journal of the Korean Ceramic Society, `` Ceramics Corrosion Characteristics under Corrosive-Resistant Silicon Carbide Corrosion Characteristics- (Vol.27, No.2, pp.161 ~ 168, 1990), '' Characteristics of Reaction Sintered Silicon Carbide (Vol.30, No.1, pp.69 ~ 77, 1993) ',' Characteristics of SiC / MoSi 2 Composite by Reaction Sintering (Vol.31, No.4, pp. 399 ~ 406, 1994) ',' Preparation of SiC Composites Using Reactive Bonded Sintering (Vol. 31, No. 5, pp.561 ~ 571, 1994) ',' Preparation of SiC-TiC Composites by Reactive Bonded Sintering ( Vol. 31, No. 8, pp. 849 to 860, 1994). However, in the case of the above patent, the contents are related to a method of manufacturing a silicon carbide ceramic heat pipe sintered body for the manufacture of a ceramic heat exchanger, and in the case of the paper, it is related to the production and evaluation of SiC composites by reaction sintering. Is different in terms of raw material composition, molding method and sintering method.
본 발명은 탄화규소와 탄소를 기본 조성으로 하고 유기바인더를 성형보조제로 첨가하여 이들을 혼합, 성형하는데 있어 탄화규소 원료의 입도, 탄소의 종류 및 첨가량 등을 변화시켜 상기에서 언급한 단점을 보완한 내열성, 내마모성 및 내식성이 우수한 특성을 갖는 세라믹 밀봉재를 제조하는데 그 목적이 있다.The present invention is made of silicon carbide and carbon as a basic composition, and the organic binder is added as a molding aid to mix and mold them, thereby changing the particle size of the carbon carbide raw material, the type and amount of carbon, etc., to compensate for the above-mentioned disadvantages. The purpose of the present invention is to prepare a ceramic sealing material having excellent properties of wear resistance and corrosion resistance.
도 1은 본 발명의 세라믹 밀봉재이다.1 is a ceramic sealing material of the present invention.
< 도면의 주요부분에 대한 부호의 설명 ><Description of Symbols for Major Parts of Drawings>
1: 밀봉재 성형체 2: 금속실리콘1: sealing material molded body 2: metal silicon
3: 질화붕소 코팅층 4: 흑연기판3: boron nitride coating layer 4: graphite substrate
본 발명의 액상 반응소결에 의한 탄화규소는 1,500∼1,700℃의 소결온도와 감압 분위기에서 용융시킨 금속 실리콘(Si)을 α-SiC와 탄소 분말로 구성된 성형체내의 기공에 모세관 현상으로 침투시켜 탄소성분과 용융침투된 실리콘과의 Si + CSiC 반응에 의해 미립의 β-SiC를 생성시키고, 이들 β-SiC 입자가 출발 모입자인 α-SiC와 결합되고 나머지 기공에 순수한 실리콘이 충전되는 메카니즘으로 제조되는 완전 치밀한 세라믹 재료이다. 따라서 이들 소결체는 강도나 내열성 등의 특성이 우수하여 고온이나 부식성 분위기하에서 내마모성, 내식성이 요구되는 곳에 광범위하게 이용되고 있다. 그러나 이러한 액상 반응소결에 의한 탄화규소는 생성된 β-SiC 또는 출발원료인 α-SiC와 반응에 의해 생성된 β-SiC 입자간의 결합력이나 조직의 균질성에 의해 크게 좌우되며, 특히 고온에서 사용될 경우에는 소결체내의 2차상(secondary phase)으로 함유된 금속 실리콘에 의해 실리콘의 융점인 1,410℃ 부근에서 고온강도가 급격히 저하되는 문제점이 있기 때문에 금속 실리콘 함유량의 적절한 제어가 매우 중요하다.Silicon carbide by the liquid phase sintering of the present invention is a carbon component by infiltrating the metal silicon (Si) melted at a sintering temperature of 1,500 ~ 1,700 ℃ and reduced pressure atmosphere by capillary phenomenon into the pores in the molded body composed of α-SiC and carbon powder Si + C with melt-penetrated silicon SiC reactions produce fine β-SiC, and these β-SiC particles are a fully dense ceramic material produced by a mechanism in which the β-SiC particles are combined with the starting parent particles α-SiC and the remaining pores are filled with pure silicon. Therefore, these sintered bodies are widely used in places where excellent wear resistance and corrosion resistance are required under high temperature and corrosive atmosphere due to excellent properties such as strength and heat resistance. However, the silicon carbide by the liquid phase sintering is greatly influenced by the bonding strength between the β-SiC produced or the starting material α-SiC and the β-SiC particles produced by the reaction or homogeneity of the tissue, especially when used at high temperatures. Proper control of the metal silicon content is very important because there is a problem that the high temperature strength is sharply decreased at around 1,410 ° C, which is the melting point of silicon, by the metal silicon contained in the secondary phase in the sintered body.
본 발명의 액상 반응소결 탄화규소 세라믹 밀봉재는 95∼85 중량의 탄화규소 분말과 5∼15 중량의 탄소분말을 사용원료로 하고, 이들 두가지 분말을 결합시킬 수 있는 성형보조제로 유기바인더를 사용한다. 이때 탄화규소 분말은 조립 (coarse powder)과 미립(fine powder)의 2성분 조합으로 첨가하고, 탄소 분말도 흑연과 카본블랙의 2성분으로 첨가한다. 이들 분말은 균일한 혼합을 위하여 진동 밀(Vibration Pot Mill)에서 약 30분간 혼합함으로써 초미립의 탄소분말이 탄화규소 분말 각각의 입자에 코팅될 수 있도록 처리한 후, 이 분말을 시그마 믹서 (Sigma-blade Mixer)에 성형보조제와 함께 넣고 약 1시간 혼합한다. 이때 성형보조제로서 사용하는 유기바인더는 카르복시메틸 셀룰로오즈(Carboxymethyl Cellulose, 이하 CMC 라고 함)나 폴리비닐 피롤리돈(Polyvinyl Pyrollidone, 이하 PVP 라고함)을 사용하고, 그 첨가량은 탄화규소와 탄소분말이 혼합된 원료량에 대해 1~2 중량를 첨가한다. 원료와 유기바인더가 혼합된 분말은 50∼100 메쉬(Mesh) 체를 통과시켜 과립화하였으며, 이 분말을 세라믹 밀봉재 성형용 금형에 넣고 일축가압법 (Uniaxial Pressing)에 의하여 300∼500kg/cm2의 압력으로 밀봉재 성형체를 제조한다.The liquid reaction sintered silicon carbide ceramic sealant of the present invention uses 95 to 85 weight of silicon carbide powder and 5 to 15 weight of carbon powder as a raw material, and an organic binder is used as a molding aid capable of combining the two powders. At this time, the silicon carbide powder is added as a two-component combination of coarse powder and fine powder, and carbon powder is also added as two components of graphite and carbon black. These powders were mixed for about 30 minutes in a Vibration Pot Mill for uniform mixing so that the ultrafine carbon powder could be coated on the respective particles of silicon carbide powder, and then the powder was mixed with a sigma mixer. Into the blade mixer together with the molding aid and mix for about 1 hour. At this time, the organic binder used as a molding aid is used as carboxymethyl cellulose (Carboxymethyl Cellulose, CMC) or polyvinyl Pyrollidone (PVP), the addition amount of silicon carbide and carbon powder mixed 1 to 2 weights are added based on the amount of the prepared raw material. The powder mixed with the raw material and the organic binder was granulated by passing through a 50-100 mesh sieve, and the powder was placed in a mold for molding a ceramic sealant, and the powder was 300-500 kg / cm 2 by uniaxial pressing. A pressure forming molded article is produced.
한편 탄화규소 분말을 조립과 미립의 2성분으로 조합하여 첨가하는 이유는 조립 분말을 단일 입도로 성형체를 제조할 경우, 성형체내에 기공이 크게 형성되어 최종 반응소결 온도에서 용융된 금속 실리콘이 빠르게 침투하여 쉽게 소결되는 장점은 있으나, 기공의 크기가 너무 크기 때문에 탄소와 실리콘과 반응 후 기공에 잔류하는 순수한 실리콘의 양이 많게 되어 기계적 및 열적 특성 및 내식성이 저하되는 단점이 있다. 반면 미립 분말을 단일 입도로 성형체를 제조할 경우에는 성형시 미립에 의한 분말의 충전도가 증가하게 되어 기공의 크기가 작게 형성되기 때문에 최종 반응소결 온도에서 용융된 금속 실리콘이 완전히 침투하지 못하는 경우가 발생되어 소결후 소결체내에 미반응 탄소에 의한 기공이 존재하게 되고, 이로 인해 기계적인 특성이 현저히 저하되는 경우가 발생하게 된다. 이에 따라 이러한 단점을 보완하기 위해서는 조립과 미립의 분말을 일정 비율로 혼합하여 성형체를 제조해야 용융 실리콘의 침투도 빠르게 진행되면서 소결 후 미반응 탄소의 존재에 의한 기공이 전혀 없는 기계적 및 열적 특성이 우수한 탄화규소 세라믹 밀봉재 성형체를 제조할 수 있다.On the other hand, the reason why silicon carbide powder is added by combining two components of granulation and fine grain is that when the granulated powder is manufactured into a single particle, large pores are formed in the molded body, and the molten metal silicon rapidly penetrates at the final reaction sintering temperature. There is an advantage that it is easily sintered, but because the size of the pores is too large, the amount of pure silicon remaining in the pores after the reaction with carbon and silicon has a disadvantage that the mechanical and thermal properties and corrosion resistance is reduced. On the other hand, in the case of manufacturing a molded body with a single particle size, the powder filling by the fine particles increases during molding, so that the pore size is formed small, so that the molten metal silicon cannot fully penetrate at the final reaction sintering temperature. After sintering, pores due to unreacted carbon are present in the sintered body, which causes a significant decrease in mechanical properties. Therefore, in order to compensate for these disadvantages, the molded body must be manufactured by mixing granulated and fine powders in a certain ratio, and the penetration of molten silicon also proceeds rapidly, and excellent mechanical and thermal properties without any pores due to the presence of unreacted carbon after sintering are achieved. A silicon carbide ceramic sealant molded article can be produced.
또한 탄소 성분으로 흑연과 카본 블랙을 2성분으로 조합하여 첨가하는 이유는 흑연을 단독 사용할 경우, 흑연과 용융침투된 실리콘이 완전히 반응한 소결체가 제조되면 기계적인 특성이 향상되는 장점이 있으나, 흑연과 실리콘의 반응에 의하여 β-SiC가 생성되는 반응속도가 늦기 때문에 미반응 흑연이 소결체내에 종종 존재하게 되고, 전체 제조공정 시간이 증가되는 단점이 있다. 한편 카본 블랙을 단독으로 사용하는 경우에는 흑연과는 달리 실리콘과의 반응속도가 매우 빨라 미반응 카본 블랙이 남지 않아 전체 제조공정 시간이 단축되는 장점은 있으나, 열역학적으로 탄소와 실리콘과의 반응이 발열반응이기 때문에 흑연에 비해 활성이 좋은 카본 블랙과 실리콘과의 β-SiC 생성반응시 심한 발열반응의 진행으로 인해 소결체가 파괴되거나 소결체에 균열이 존재하는 경우가 종종 발생하게 된다. 이에 따라 흑연과 카본 블랙을 2성분으로 하여 균일하게 혼합함으로써 기계적인 특성을 향상시키면서 소결 후 균열 등의 결함이 없는 탄화규소 세라믹 밀봉재 성형체를 제조할 수 있다.In addition, the reason for adding a combination of graphite and carbon black as two components as a carbon component is that when graphite is used alone, the mechanical properties are improved when the sintered body in which the graphite and the melt-penetrated silicon are completely reacted is produced. Due to the slow reaction rate at which β-SiC is produced by the reaction of silicon, unreacted graphite is often present in the sintered body, and the overall manufacturing process time is increased. On the other hand, when carbon black is used alone, unlike graphite, the reaction rate with silicon is very fast, so that unreacted carbon black does not remain, which shortens the entire manufacturing process time, but thermodynamically, the reaction between carbon and silicon generates heat. Because of the reaction, during the β-SiC formation reaction between carbon black and silicon, which is more active than graphite, the sintered compact is often destroyed due to the progress of severe exothermic reaction. As a result, by uniformly mixing graphite and carbon black as two components, it is possible to produce a silicon carbide ceramic sealing material molded product free from defects such as cracks after sintering while improving mechanical properties.
밀봉재 성형체를 제조한 후 도 1과 같이 질화붕소(Boron Nitride, BN)가 도포된 흑연 기판위에 밀봉재 성형체를 놓고 각각의 성형체 링 안쪽에 금속 실리콘 분말을 넣고 실온에서 10-1∼10-2torr의 감압분위기에서 800℃까지 1∼2℃/분의 느린 속도로 승온시키면서 1시간 유지하여 성형체내에 포함된 유기 바인더를 완전히 연소시켜 성형체에 개기공(open pore)을 만들어 줌으로써 금속 실리콘의 용융시 밀봉재 성형체 내부로 원활히 침투되게 한다. 800℃에서 열처리가 끝나면 1,550∼ 1,600℃까지 5℃/분의 승온속도로 승온하고 1시간 동안 유지시킨 후, 다시 1,700℃까지 승온시켜 1시간 동안 유지함으로써 세라믹 밀봉재를 제조한다. 이때 1,550∼1,600℃에서의 유지시간은 용융침투한 실리콘과 탄소가 불완전한 반응에 의한 미반응 탄소를 남기지 않도록 하고, 기공을 실리콘으로 충전시킴으로써 소결 후 기공이 없는 완전 치밀한 소결체를 제조하기 위한 조건이며 1,700℃에서의 유지시간은 탄소와 실리콘과의 반응에 의해 생성된 β-SiC의 입성장(grain growth) 유도 및 이에 의한 α-SiC와 충분한 결합을 위한 시간이다.After preparing the sealing member molded body, the sealing member molded body was placed on the graphite substrate coated with boron nitride (BN) as shown in FIG. 1, and the metal silicon powder was put inside each molded ring, and the temperature was 10 -1 to 10 -2 torr. Sealing material for melting of metal silicon by making open pores in the molded body by completely burning the organic binder contained in the molded body by maintaining the temperature for 1 hour while increasing the temperature at a low speed of 1 to 2 ° C / min from a reduced pressure atmosphere. Allows smooth penetration into the moldings. When the heat treatment is completed at 800 ℃ to 1,550 ~ 1,600 ℃ to increase the temperature at a rate of 5 ℃ / min and maintained for 1 hour, and then heated to 1,700 ℃ to maintain for 1 hour to prepare a ceramic sealing material. At this time, the holding time at 1,550 ~ 1,600 ℃ is a condition for producing a completely dense sintered body without pores after sintering by filling the pores with silicon to avoid leaving unreacted carbon due to incomplete reaction between the molten and impregnated silicon and carbon. The holding time at ° C is the time for inducing grain growth of β-SiC produced by the reaction of carbon with silicon and thereby sufficient bonding with α-SiC.
이하 본 발명을 다음의 실시예 및 시험예에 의하여 설명하고자 한다. 그러나 이들이 본 발명의 기술적 범위를 제한하는 것은 아니다.Hereinafter, the present invention will be described by the following examples and test examples. However, these do not limit the technical scope of the present invention.
＜ 실시예 1 ＞<Example 1>
평균입경 22㎛와 3㎛인 조립과 미립의 탄화규소 분말(Cica, Norway) 혼합비율을 70 중량: 30 중량로 하고, 평균 입경 1㎛ 미만의 흑연과 카본 블랙(LG 카본, 국내)의 탄소분말 혼합비율을 60 중량: 40 중량로 하였으며, 전체적으로 탄화규소 분말과 탄소 분말 혼합비율을 92.5 중량: 7.5 중량로 혼합하여 원료로 준비하였다. 그런 다음 진동 밀을 이용하여 상온에서 30분간 탄화규소 분말과 탄소분말을 더욱 균일하게 혼합한 후, 유기바인더인 CMC(한국 고재) 또는 PVP(Aldrich, U.S.)를 원료의 1.5 중량만큼 첨가하고 시그마 믹서에서 원료와 유기바인더를 혼합한다. 그런 다음 원료와 유기혼합물의 혼합물을 50메쉬 체를 통과시켜 과립화 한 후, 금형에서 300∼500kg/cm2의 압력으로 일축가압하여 세라믹 밀봉재 성형체(1)를 제조하였다.10-1∼10-2torr의 감압 분위기가 유지되고 도 1과 같이 질화붕소(3)가 도포된 흑연기판(4) 위에 밀봉재 성형체(1)를 두고 밀봉재 성형체(1) 사이에 금속실리콘(silicon metal, FCT, Germany)(2)을 넣고 금속실리콘(2)을 용융시켜 밀봉재 성형체(1) 내에 침투시기기 위해 진공 저항가열로에서 800℃에서 1시간 열처리한 후, 1,600℃까지 5℃/분의 승온속도로 승온하고 1시간 동안 유지시킨 후, 다시 1,700℃까지 승온시켜 1시간 동안 유지함으로써 액상 반응소결에 의해 흑연과 카본 블랙이 첨가된 탄화규소 세라믹 밀봉재를 제조하였다.Granulated and fine grained silicon carbide powder (Cica, Norway) with an average particle diameter of 22 µm and 3 µm was 70 weight: 30 weight, and carbon powder of graphite and carbon black (LG carbon, domestic) with an average particle diameter of less than 1 µm. The mixing ratio was 60 weight: 40 weight, and the silicon carbide powder and carbon powder mixing ratio were mixed to 92.5 weight: 7.5 weight as a raw material. Then, the silicon carbide powder and carbon powder were mixed more uniformly at room temperature for 30 minutes using a vibration mill, and then organic binder, CMC (Korean solid material) or PVP (Aldrich, US), was added by 1.5 weight of the raw material and sigma mixer. Mix the raw material with the organic binder. Then, the raw material and the mixture of the organic mixture and then granulation was passed through a 50-mesh screen, by uniaxial pressing in a mold at a pressure of 300~500kg / cm 2 to prepare a ceramic sealing material molded product (1) to 10 -1 .10 - A pressure reducing atmosphere of 2 torr is maintained and the sealing material molded body 1 is placed on the graphite substrate 4 coated with boron nitride 3 as shown in FIG. 1, and the metal silicon (FCT, Germany) is placed between the sealing material molded bodies 1. (2) was added, the metal silicon (2) was melted, and heat-treated at 800 ° C. for 1 hour in a vacuum resistance heating furnace to penetrate into the sealing member molded body 1, and then the temperature was raised to 1,600 ° C. at a temperature rising rate of 5 ° C./min. After maintaining for 1 hour, the temperature was further raised to 1,700 ° C. and maintained for 1 hour to prepare a silicon carbide ceramic sealing material in which graphite and carbon black were added by liquid phase sintering.
＜ 실시예 2 내지 9 ＞<Examples 2 to 9>
아래의 표 1에 나타낸 조성물과 상기 실시예 1에 기재된 액상 반응소결 방법에 의해 탄화규소 세라믹 밀봉재를 제조하였다.A silicon carbide ceramic sealing material was prepared by the composition shown in Table 1 below and the liquid phase sintering method described in Example 1.
표 1. 탄화규소 세라믹 밀봉재 제조를 위한 원료분말 조합Table 1. Raw Material Powder Combinations for Manufacturing Silicon Carbide Ceramic Sealants
＜ 시험예 ＞<Test example>
상기 실시예 1∼9에 의해 흑연과 카본 블랙이 첨가된 탄화규소 세라믹 밀봉재의 상대밀도, 기공율, 꺾임강도와 같은 특성 값을 측정하여 그 결과를 아래의 표 2에 나타내었다. 여기에서 상대밀도(Relative Density), 기공율(Porosity)은 탄화규소의 이론밀도를 3.21g/cm3으로 하여 KSL 3114에 준하여 측정하였으며, 꺾임강도는 본 발명에서의 밀봉재와 같이 링(ring) 형태인 세라믹 제품의 강도 측정법인 C-ring 3점-꺾임강도 시험법에 의하여 측정하였다.In Examples 1 to 9, characteristic values such as relative density, porosity, and bending strength of the silicon carbide ceramic encapsulant added with graphite and carbon black were measured, and the results are shown in Table 2 below. Relative density and porosity were measured according to KSL 3114 with the theoretical density of silicon carbide as 3.21 g / cm 3 , and the bending strength was in the form of a ring like the sealant in the present invention. It measured by the C-ring 3-point bending test method which is a strength measurement method of a ceramic product.
표 2. 각 실시예의 탄화규소 세라믹 밀봉재의 특성 값Table 2. Property Values of Silicon Carbide Ceramic Sealants of Each Example
본 발명의 액상 반응소결법은 고가의 소결조제를 첨가하지 않고 1,500∼ 1,700℃의 낮은 온도에서 소결이 가능할 뿐만 아니라, 소결반응이 매우 빠르게 진행되고 소결시 수축이나 팽창 등의 치수변화가 거의 없어 정밀치수, 복잡한 형상, 대형의 제품을 쉽게 소결할 수 있다. 본 발명은 이러한 소결법을 이용하여 경도, 내마모성 및 내열성이 우수한 세라믹 밀봉재를 제공하여 내구성 향상에 의한 원가절감 및 에너지비용을 절감할 수 있다.The liquid phase sintering method of the present invention is capable of sintering at a low temperature of 1,500 to 1,700 ° C. without adding an expensive sintering aid, and also has a precise dimension because the sintering reaction proceeds very fast and there is almost no dimensional change such as shrinkage or expansion during sintering. Easy to sinter complex shapes and large products. The present invention can provide a ceramic sealing material excellent in hardness, wear resistance and heat resistance by using such a sintering method can reduce the cost and energy costs by improving the durability.
Claims (4)
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| KR100867961B1 (en) * | 2007-12-14 | 2008-11-10 | 주식회사 월덱스 | Alpha;type sic- beta; type sic combined reaction sintering sic material and manufacture method and plasma chamber cathode that use it |
| CN105198439B (en) * | 2015-09-24 | 2017-12-29 | 山东金鸿新材料股份有限公司 | A kind of armour silicon carbide green body and preparation method thereof |
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