고화도 탄화번조의 특징에 관한 연구

장석현 한국도자학회 2024 한국도자학연구 Vol.21 No.2

탄화번조, 꺼먹이 구이, 침탄소성은 검댕을 도기질에 입히는 목적으로 사용되는 번조 방식이다. 이러한 기법이 발달한 한, 중, 일 국가는 다양한 방법으로 태토에 탄소를 가둬두는 방식을 가지고 있다. 청자가 제작되기 전 연, 경질도기의 제작 방법으로 활용되었던 탄화번조는 강도와 방수등 기능성을 목적으로 건축과 생활용품 장식품 제작을 위해 실행되었다. 본 연구는 탄화번조의 방식을 1000℃를 기준으로 구분하고 그 이상의 온도인 고화도 탄화번조 방법과 특징에 대해 밝히고자 한다. 기와, 전돌, 질그릇 등은 900℃~ 1100이하의 온도에서 번조되며, 그 이상의 온도에서 번조되는 경질도기인 푸레도기는소금이 기화되고 용융되는 온도인 1150~1210℃에서 탄화번조가 실행된다. 재가 용융 될 정도로 높은온도에서 강도 있는 탄화 경질도기는 삼국시대에서부터 제작되어 왔으며 근대까지 활발히 제조 사용되었다. 현대에는 전통방식의 옹기생산과 경질도기, 도예 작품제작에 활용되고 있다. 이 연구의 의도는고화도 탄화번조가 어떻게 실행되고 어떠한 조건에서 반응되는지를 밝히는 것이다. 저화도 탄화번조의방식은 태토 기공에 탄소를 침투시키는 작용이라면, 고화도 탄화번조는 탄소와 철분인 금속산화물과의용융결합인 고용1)(solid dissolution)과 침탄2)(carburizing)을 특징으로 한다. 그러므로 철분이 없는 상태의 점토는 고화도 탄화번조에는 부적합한 소재라고 할 수 있다. 그러므로 철분이 0%에 가까운 백자태토는 고화도 탄화번조 시 태토의 기공사이로 침탄하지 않는 점을 밝히고, 백자태토에 산화철을 첨가하여 탄화된 결과물을 밝히고 산화철 함유량이 같은 탄화옹기태토와 비교하였다. 시편은 백자태토와 산화철을 함유한 백자태토, 산화코발트, 산화구리, 산화크롬이 함유된 백자태토, 시유된 각 시편들로 제작되었으며, 번조는 장작가마 푸레그릇 번조, 가스가마 탄화번조, 내화벽돌 실험 가마를 제작하여 탄화번조를 실행하였다. 그 결과 백자태토에는 탄소반응이 없거나 미미했고, 철분함량이 많을수록 탄소와의 반응이 많다는 결과가 나타났다. 다른 금속산화물과인 산화코발트, 산화구리, 산화크롬반응은 미미했다. 고화도 탄화번조는 태토가 소결될 때 용융된 금속산화물의 결합상, 철분과의 탄소결합 반응으로 고용, 침탄의 결과가 나타난다고 할 수 있다. Carbonization firing, charcoal firing, and carburizing are firing methods used for the purpose of coating the pottery with soot. Countries such as Korea, China, and Japan, where these techniques were developed, have various methods of trapping carbon in the clay. Carbonization firing, which was used as a method of producing soft and hard pottery before celadon was produced, was carried out for the purpose of producing architectural and household ornaments with the purpose of strength and waterproofing. This study categorizes the carbonization firing method based on 1000℃ and aims to elucidate the characteristics of the high-temperature carbonization firing method at a temperature higher than that. Roof tiles, bricks, and earthenware are fired at temperatures between 900℃ and 1100℃, while hard pottery fired at a temperature higher than that, puredogi, is fired at 1150~1210℃, the temperature at which salt vaporizes and melts. Carbonized hard pottery with strength at a temperature high enough to melt ash has been produced since the Three Kingdoms period and has been actively manufactured and used until modern times. In modern times, it is used for traditional pottery production, hard pottery, and ceramic art production. The purpose of this study is to clarify how high-temperature carbonization firing is performed and under what conditions it reacts. If the low-temperature carbonization firing method is the action of penetrating carbon into the pores of the clay body, high-temperature carbonization firing is characterized by solid solution and carburization, which are melting bonds between carbon and metal oxides such as iron. Therefore, clay without iron can be said to be an unsuitable material for high-temperature carbonization firing. Therefore, it was clarified that white porcelain clay with close to 0% iron does not carburize between the pores of the clay body during high-temperature carbonization firing, and the carbonized result by adding iron oxide to white porcelain clay was clarified and compared with carbonized pottery clay with the same iron oxide content. The specimens were made of porcelain clay, porcelain clay containing iron oxide, porcelain clay containing cobalt oxide, copper oxide, and chromium oxide, and glazed specimens, and the firing was performed in a wood-fired kiln for puree bowl firing, a gas kiln for carbonization, and a refractory brick experimental kiln for carbonization. As a result, the porcelain clay had no or minimal carbon reaction, and the higher the iron content, the greater the reaction with carbon. The reactions with other metal oxides, such as cobalt oxide, copper oxide, and chromium oxide, were minimal. It can be said that the high-fidelity carbonization firing is the result of solid solution and carburization due to the bonding phase of the molten metal oxide when the clay is sintered and the carbon bonding reaction with iron.

Pressure Effects on the Morphology Development of C/C Composites During Carbonization

Joo, Hyeok-Jong,Ryu, Seung-Hee,Ha, Hun-Seung 한국탄소학회 2001 Carbon Letters Vol.1 No.3

It is well known that the fabrication process of carbon/carbon composites is very complex. Above all, the carbonization process have major effect on the morphology development of carbon matrix. Carbon/carbon composites of 4-directional fiber preform were fabricated using the coal tar based pitch as a matrix precursor in this study. According to carbonization pressure of 1 bar, 100 bar, 600 bar, and 900 bar, morphological changes of cokes and matrix of composites were discussed. As the carbonization pressure increased to 600 bar, the flow pattern morphology of bulk mesophse was well developed. On the contrary, mosaic pattern morphology was found in case of 900 bar of carbonization pressure. It is confirmed that the carbonization pressure have profound effect on the degree of graphitization and crystal size of carbon matrix. Even in the highly densified carbon/carbon composites, large voids were still found in the matrix pocket region.

Nd:YAG Laser 직접 각인을 이용한 Carbon 스트레인 센서

주동현,윤상우,김주한,박우태,Joo, Donghyun,Yoon, Sangwoo,Kim, Joohan,Park, Woo-Tae 한국마이크로전자및패키징학회 2018 마이크로전자 및 패키징학회지 Vol.25 No.1

Nd:YAG Laser를 이용하여 polyimide film에 탄화(carbonization)를 진행하여 Carbon을 생성하여 저가의 센서를 간단한 제조과정으로 만들었다. 이를 통하여 유연한 저가형 압저항 센서의 특성에 관한 연구를 수행하였다. 기존에 많은 연구들이 Polyimide에 $10.6{\mu}m$의 파장을 가지는 $CO_2$ laser를 이용하여 carbonization을 하여 센서를 제작하였다. 본 논문에서는 polyimide film에 $1.064{\mu}m$의 파장을 가지는Nd:YAG laser를 이용하여 carbonization(탄화공정)을 진행하였다. 또한 Nd:YAG laser를 사용하여 polyimide film위에 직접 탄화시키며 carbon을 생성하는 최적의 전력밀도($W/cm^2$)과 속도(scan rate) 조건 조합을 찾아 해상도를 높였다. $CO_2$ laser를 사용하였던 기존의 선행연구에서는 carbon생성의 최소 선폭이 $140{\sim}220{\mu}m$의 길이를 가졌지만, 본 연구에서는 카본의 생성되는 선폭이 $35{\sim}40{\mu}m$으로 축소시켰다. 이번 연구에서 제작된 센서의 초기 면저항은 $100{\sim}300{\Omega}/{\square}$ 이였다. 곡률 반경 21 R 로 인장을 하였을 때 저항이 30% 줄어들었고, 이를 통하여 계산된 게이지 팩터는 56.6이였다. 본 연구는 압저항 센서를 제조하기 위한 단순하고, 매우 유연하고 저렴한 공정을 제공한다. Nd:YAG laser was used to carbonize polyimide films to produce carbon films. This is a simple manufacturing process to fabricate low cost sensors. By applying this method, we studied characteristics of flexible and low-cost piezoresistive. Previously, many studies focused on carbonization of polyimide using $CO_2$ laser with wavelength of $10.6{\mu}m$. In this paper, carbonization (carbonization process) was performed on polyimide films using an Nd:YAG laser with a wavelength of $1.064{\mu}m$. In order to increase the resolution, we optimized the laser conditions of the power density ($W/cm^2$) and the beam scan rate. In previous studies using $CO_2$ laser, the minimum line width was $140{\sim}220{\mu}m$ but in this study, carbon line width was reduced to $35{\sim}40{\mu}m$. The initial sheet resistance of the carbon sensor was $100{\sim}300{\Omega}/{\square}$. The resistance decreased by 30% under stretched with a curvature radius of 21 R. The calculated gauge factor was 56.6. This work offers a simple, highly flexible, and low-cost process to fabricate piezoresistive sensors.

Pressure Effects on the Morphology Development of C/C Composites During Carbonization

Hyeok-Jong Joo,Seung-Hee Ryu,Hun-Seung Ha 한국탄소학회 2001 Carbon Letters Vol.1 No.3

It is well known that the fabrication process of carbon/carbon composites is very complex. Above all, the carbonization process have major effect on the morphology development of carbon matrix. Carbon/carbon composites of 4-directional fiber preform were fabricated using the coal tar based pitch as a matrix precursor in this study. According to carbonization pressure of 1 bar, 100 bar, 600 bar, and 900 bar, morphological changes of cokes and matrix of composites were discussed. As the carbonization pressure increased to 600 bar, the flow pattern morphology of bulk mesophse was well developed. On the contrary, mosaic pattern morphology was found in case of 900 bar of carbonization pressure. It is confirmed that the carbonization pressure have profound effect on the degree of graphitization and crystal size of carbon matrix. Even in the highly densified carbon/carbon composites, large voids were still found in the matrix pocket region.

Effect of kneading and carbonization temperature on the structure of the carbon block for thermally conductive bulk graphites

An Donghae,김경훈,Lim Chaehun,이영석 한국탄소학회 2021 Carbon Letters Vol.31 No.6

Artifcial graphites have been used in various applications, for example, as anode materials for Li-ion batteries, C/C composites, and electrodes for aluminum smelting, due to their unique mechanical strength and high thermal and electrical conductivity. Artifcial graphites can be manufactured by a series of kneading, molding, carbonization and graphitization processes with an additional impregnation process. In this study, the infuence of the process variables in the kneading and carbonization/graphitization process on the properties of the resulting carbon block was systemically investigated. During the kneading process, the optimum kneading temperature was 90 °C higher than the softening point of the binder pitch; thus, the binder pitch reached its maximum fuidity. On the other hand, during the carbonization and graphitization process, the structural properties of carbon blocks prepared at diferent heat treatment temperatures were examined and their structural change and evolution were closely described according to the temperature and divided into low-temperature carbonization and high-temperature carbonization/graphitization. Based on this study, we expect to provide a better understanding of setting the parameters for thermally conductive carbon block manufacturing.

Formation of Isotropic Carbon Matrix in Carbon/Carbon Composites Derived from Pitch

Chong-Jin Ahn,In-Seo Park,Hyeok-Jong Joo 한국탄소학회 2010 Carbon Letters Vol.11 No.4

To manufacture a carbon/carbon composite the coal tar pitch was used as the matrix precursor and the PAN (polyacrylonitrile)-based carbon fiber was used as the reinforcing material to weave 3-directional preform. For pressure carbonization HIP equipment was used to produce a maximum temperature of 1000℃ and a maximum pressure of 100 MPa. The carbonization was induced by altering the dwell temperature between 250℃ and 420℃, which is an ideal temperature for the moderate growth of the mesophase nucleus that forms within the molten pitch during the pressure carbonization process. The application of high pressure during the carbonization process inhibits the mesophase growth and leads to the formation of spherical carbon particles that are approximately 30 nm in size. Most particles were spherical, but some particles were irregularly shaped. The spread of the carbon particles was larger on the surface of the carbon fiber than in the interior of the matrix pocket.

Investigation of Narrow Pore Size Distribution on Carbon Dioxide Capture of Nanoporous Carbons

Long-Yue Meng,박수진 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.11

Nanoporous carbons with a high specific surface area were prepared directly from thermoplastic acrylic resin as carbon precursor and MgO powder as template by carbonization over the temperature range, 500-1000 °C. The effect of the carbonization temperature on the pore structure and CO2 adsorption capacity of the obtained porous carbon was examined. The textural properties and morphology of the porous carbon materials were analyzed by N2/−196 °C and CO2/0 °C adsorption/desorption isotherms, SEM and TEM. The CO2 adsorption capacity of the prepared porous carbon was measured at 25 °C and 1 bar and 30 bar. The specific surface area increased from 237 to 1251 m2/g, and the total pore volumes increased from 0.242 to 0.763 cm3/g with increasing the carbonization temperature. The carbonization temperature acts mainly by generating large narrow micropores and mesopores with an average pore size dependent on the level of carbonization of the MgO-templated nanoporous carbons. The results showed that the MgO-templated nanoporous carbons at 900 °C exhibited the best CO2 adsorption value of 194 mg/g at 1 bar.

배추를 이용한 활성탄 제조에 관한 연구

이성헌,이봉헌,박흥재 한국환경과학회 2001 한국환경과학회지 Vol.10 No.5

In recent years, the demand of activated carbon has been increasing steadily because of the environmental problems. Among them waste and water treatment and removal of poisonous gas were involved. Therefore, in this study, activated carbon was made from the waste chinese cabbage and measured the iodine adsorption ability, carbonization yield, and activation yield of the produced activated carbon. The result showed that the carbonization yield was decreased when carbonization temperature was increased and that the optimal carbonization temperature was 600℃. The optimal concentration of NaOH for removing ash in the raw sample was 1∼2N. The range of iodine adsorption number of activated carbon using chinese cabbage at 600℃ carbonization was 610.82㎎/g to 1019.58㎎/g. The activation result of carbonization sample showed that the optimal activation condition was the carbonization at 400℃ and the activation at 700℃. So the production of activated carbon using chinese cabbage was possible in the aspect of reuse of resource and decrease of environmental pollution compared to the commercial activated carbon.

수증기 활성화법으로 제조된 활성탄의 탄화온도에 따른 세공구조 고찰

이송우,나영수,김도한,최동훈,류동춘,송승군 한국환경과학회 2000 한국환경과학회지 Vol.9 No.4

Activated carbons were prepared from Korean coal by steam activation in this study. The variation of pore structure of the activated carbons were investigated according to different carbonization temperatures. Yield, surface area, pore volume and pore structure of this activated carbon were compared with those of activated carbon prepared without carbonization. The investigated carbonization temperature ranged from 700℃ to 1,000℃. Carbonization was carried out in nitrogen atmosphere for 70 minutes and activation was performed by steam at 950℃ for 210 minutes. Surface area and pore volume of the resulting activated carbons increased with carbonization temperature. Also pore volume increased by 20% compared to the activated carbon without carbonization. Especially, in mesopore region, the activated carbon carbonized at 900℃ had more pores by 60% than that of activated carbon carbonized at other temperature.

하수슬러지의 수열탄화를 통한 고형연료 탄화 특성

한성국,김문일 유기성자원학회 2023 유기물자원화 Vol.31 No.2

Most of the sewage sludge is organic waste containing a large amount of organic substances decomposable by microorganisms by biological treatment. As for existing sewage sludge treatment methods, reduction and fuel conversion are being carried out using technologies such as drying, incineration, torrefaction, carbonization. However, the disadvantage of high energy consumption has been pointed out as latent heat of 539 kcal/kg is consumed based on drying. Therefore, in this study, we intend to produce solid fuel through hydrothermal carbonization(HTC), which is a thermochemical treatment. To evaluate the value of solid fuel, the characteristics of carbonization and fuel ratio were analyzed. As a result, as the hydrothermal carbonization reaction temperature increased, the lower heating value also increased by about 500 kcal/kg due to the increase in the degree of carbonization. H/C, O/C, ratio showed a decreasing trend from 1.78, 0.46 to 1.57, 0.32. When the ratio of ash to combustible content (fixed carbon + volatile) of dry sludge was 0.25 or more, it was derived that the degree of carbonization and calorific value did not increase even when hydrothermal carbonization was performed. 하수슬러지의 대부분은 생물학적 처리에 의한 미생물에 의해 분해 가능한 유기물질을 다량 함유하고 있는유기성 폐기물이다. 기존의 하수슬러지 처리방법으로는 건조, 소각, 반탄화 그리고 탄화 등의 기술을 이용하여감량화 및 연료화를 진행하고 있다. 그러나, 건조를 기반으로 하여 539kcal/kg의 잠열이 소비됨으로 에너지 소비가높은 단점이 지적되고 있다. 따라서 본 연구에서는 열화학적 처리인 수열탄화(HTC)를 통해 고형연료를 생산하고자한다. 고형연료의 가치를 평가하기 위하여 탄화도 및 연료비의 특성을 분석하였다. 그 결과 수열탄화 반응온도가증가할수록 탄화도의 상승으로 저위발열량도 약 500kcal/kg 상승하였다. H/C, O/C, Ratio는 1.78, 0.46에서 1.57, 0.32로감소하는 경향을 보였다. 건조슬러지의 가연분(고정탄소+휘발분) 대비 회분(Ash)의 비율이 0.25 이상으로 나타날경우는 수열탄화를 진행하여도 탄화도 및 발열량의 증가되지 않는다는 것을 도출하였다.