세라믹 생체 재료

김택남 한국세라믹학회 2002 세라미스트 Vol.5 No.1

고Mn강의 소성에 따른 미세조직및 Texture 변화에 관한연구

김택남,김종옥,Kim, Taek-Nam,Kim, Jong-Ok 배재대학교 자연과학연구소 1995 自然科學論文集 Vol.7 No.-

탄소함량이 다른 두 Hadfield's강의 (고Mn강) 소성에 관한 연구를, 냉간압연시 나타나는 금속미세조직, texture등으로 조사하였다. Low carbon Hadfield's steel (LCHS, 0.65 wt. % C)에서는 적층결함, 쌍정및 brass type shear bands가 냉간압연시 나타나고, 이때 쌍정은 Intrinsic적층결함이 차곡차곡 쌓여서 나타나는것으로 생각된다. Texture 는 70-30 황동과 초기에는 비슷하나, 40% 이상의 변형에서는 마르텐사이트 상변화에 의해서 이상 texture가 나타난다. 한편 high carbon Hadfield's steel (HCHS, 1.35 wt. % C)에서는 전위엉킴, 쌍정및 copper and brass type shear bands가 소성 변형시 나타난다. Texture 는 70-30 황동과 비슷하고 이상 texture는 나타나지않고있다. 이러한 사실은 HCHS에서 마르텐사이트 상변화가 나타나지 않는것과 또 탄소원자가 편석되지 않는것과 잘일치하고 있다. LCHS와 HCHS사이의 미세조직과 texture의 변화에 많은 차이점을 보일지라도, 적층결함에너지의 차이는 매우작고 약 ($2 mJm^-2$), 탄소편석이 오직 LCHS에서만 일어나고 있다. 따라서 탄소와 같은 작은 원자의 편석이 미세조직 뿐만아니라, texture에 영향을 미치는 것을 생각 할 수 있다. 이러한 탄소의 편석은 LCHS에서 마르텐사이트 상변화와도 관계가 깊다. The microstructural and textural development during rolling is compared in two Hadifield's steels (high Mn steel), one having low carbon content (0.65 wt.%) and the other high carbon (1.35 wt.%).In low carbon Hadfield's steel (LCHS) mixed microstructures are formed which contain intrinsic stacking faults, deformation twins, and brass type shear bands. The deformation twins are thought to be formed by the stacking of intrinsic stacking faults. The similar development to 70-30 brass texture is observed in early deformation. However the abnormal texture is developed after 40 % deformation, which is thought to be due to the martensite phase transformation. In high carbon Hadfield's steel (HCHS) mixed substructures of dislocation tangles, deformation twins, and shear bands (both copper and brass type) are found to develop. The texture development is similar to that of 70-30 brass. This is consistant with no carbon segregation and no martensitic phase transformation in HCHS. In spite of the difference of substructure and texture development during rolling in two steels, the difference in stacking fault energy is measured to be small ($2 mJm^-2$). The carbon segregation is only occurred in LCHS. Thus it is thought that the carbon segregation influence the microstructure and texture development during rolling. This is related with martensite phase transformation in LCHS.

The Functions In Coleridge's Idea of Imagination

김택남 牧園大學校 1981 論文集 - 牧園大學校 Vol.4 No.-

In the preceding pages, Coleridge is seen as a writer in his roles of literary critic, and poet. The following remarks are intended to summarize his critical principles and to indi-cate where his poetic excellence. Coleridge wrote two kinds of poetry that really mattered: the conversational poems and the poems of high imagination. They incorporate his critrcal theories: 'organic unity, the reconciliation of opposites'. To keep this principle in mind is rathera chore, Coleridge used this term for 'the poet, described in ideal perfection,' the poet as the focal point of poetic unity. 'The 'whole suul of man' is brought into activity,' ard thereby comes 'a tone and spirit of unity.' It is a unity that demands, 'the balance or reconciliation of opposites or discordant qualities': sameness and difference; generals and concretes; ideas and images; the individual and the representative; novelty and familiarity; emotion and order, judgement and feeling; the natural and the artificial; the poet and his poems. In Coleridge, who is rathera chore, Coleridge used this term for 'the poet, described in ideal perfection,' the poet as the focal point of poetic unity. 'The 'whole soul of man' is brought into activity,' and thereby comes 'a tone and spirit of unity.' It is a unity that demands, 'the balance or reconciliation of opposites or discordant qualities' : sameness and difference; generals and concretes; ideas and images; the individual and the representative; novelty and familiarity; emotion and order, judgement and feeling; the naatural and the artificial; the poet and his poems. In Coleridge, who is pre-eminently a poet of imagination, these are reduced to a unified and organic shape. The function of imaginative poetry is to create a unified and significant pattern of the Chaos and welter of experiences. That is precisely why, as Coleridge says, the whole personality of the poet is engaged in the imaginative process. In Coleridge, as J. B. Beer says, the shaping spirit and the inquiring spirit were equally strong, and he was never happier than when exercising both to the limit of their powers. There is indeed, in Coleridge, a new poetic vision. It is a vision from which nothing seems to be left out: the poet, his thoughts and feelings, the world of man. and the world of nature, the world of universal values whatever man can know. He fused all these things into a new being. We may call this new being, as Coleridge does, a symbol. When considering his individual, 'Kubla Khan' is a poem of high imagination. In the fragmentary" Kubla Khan," the poet sets before the reader two worlds, that of the ima-gination and that of understanding. That latter is the world in which all men are more of less at home; it is a world in which the poet enters Eden, so to speak, on the viewless wings or poesy. Coleridge attempts in "Kubla Khan" to portray the world of imagination pictu-resquely in terms of sunlit caverns and floating pleasure-domes, in effect, he tries to re-create creativity in action. The "caverns measureless to man," like the "sunless sea" and "lifeless ocean." are all remote from the actual world. Such settings are unknown to the faculty of the understan-ding or, more simply, to common-sense man in the beanfield world. The "caverns mea-sureless to man" are twice mentioned in order to emphasize the point that man's under-standing, that is his quantitative abilities, are insufficient. They can neither measure the caverns, nor provide entry into this second world. The above images all belong to this second world of the imagination. The next significant lines (Ⅱ . 29-30) "ancestral voices prophosying war" heard by Kubla, but heard "from afar"; that is heard from that distant land of the understanding belonging only to the common-sense man. The scene shifts to accent the pleasure-dome. This of an ideal world makes the poet exclame: "It was a miracle of rare device, A sunny pleasure-dome with caves of ice!"(Ⅱ35-36) Only in the ideal world could such Ioveliness be realized; "singing of Mount Abora" - singing of distant lands of enchantment and mystery. In the last line, the poet create mysterious ambrosia ("honey-dew" and "Milk of paradise) fit for inhabitants of that world of poetic imagination. These seemingly antithetical images combine to demonstrate the proximity of the known and the unknown worlds, the two worlds of understanding and imagination, the two worlds of common-sense and mystery.

Coleridge 以後 想像力說의 展開에 대하여

金澤南 청주대학교 국제문제연구원 1984 國際文化硏究 Vol.1 No.-

HAp와 알루미나 결합에 있어서의 중간 유리상 연구

김택남,김종옥,조성준,Kim, T.N.,Kim, J.O.,Cho, S.J. 배재대학교 자연과학연구소 1995 自然科學論文集 Vol.8 No.1

알루미나와 Hydroxyapatite(HAp)의 결합을 연구하기 위하여 9 가지의 중간 유리상을 연구하였다. 그 중간상의 화학 조성은 $CaO-Al_2O_3$에서 정하였으며 CaO/$Al_2O_3$의 몰 비율은 0.5에서 3 까지 변화 시켰다. 가장 낮은 용융은 CaO/$Al_2O_3$의 몰 비율이 2이고 $1355^{\circ}C$때 나타났다. $Al_2O_3$의 양을 증가시킴에 따라 용융점은 점점 높아 졌고 많은 기공들이 발견 되었다. 단면 조직 조사에 따르면 높은 CaO양 시편에서 양호한 흡수접착을 발견할 수 있었고, 이것은 CaO/$Al_2O_3$ 비가 2보다 큰것에서 더좋은 흡수접착을 얻을 수 있음을 의미한다. 열처리후 상변태는 발견되었으나, HAp의 중요한 피크는 그대로 남아 있음을 알 수 있다. Several intermediate glasses are investigated to bond the alumina and the hydroxyapatite (HAp). The chemical compositions of the intermediate glasses are chosen as $CaO-Al_2O_3$. The mole ratio of CaO/$Al_2O_3$ is changed from 0.5 to 3.0. The lowest melting is observed at $1355^{\circ}C$ in the specimen of CaO/$Al_2O_3$ at the mole ratio of 2. With increasing contents of $Al_2O_3$, the melting temperatures gradually increase and a number of pores are observed. The sectional microstructure shows that the good wetability is observed in higher contents of CaO specimens. This implies that the good wetability is obtained in the mole ratio range of CaO/$Al_2O_3geq2$. The phase transformations are observed after treatment but the major peaks of HAp still exist.

Al - brass 의 해수부식에 관한 연구

김택남,김종희 ( Taik Nam Kim,Chong Hee Kim ) 한국부식방식학회 1980 Corrosion Science and Technology Vol.9 No.2

치과용 YSZ 투과율 향상을 위한 중화(세척) 공정 및 Ti 이온 효과

박세민, 김택남 배재대학교 공학연구소 2016 공학논문집 Vol.18 No.1

Zirconium oxy chloride solution was hydrothermally synthesized by hydrothermal synthesis at 130℃ for 24 hours. After that, neutralization(washing) and addition of Ti-sol were added as parameters and calcined at 900℃ for 2 hours. The powder was analyzed by X-ray diffraction(XRD) and scanning electron microscope(SEM). molded to 25mm x 25mm x 1mm to measure transmittance, particle size analysis, density and hardness. The main crystal phase was tetragonal nanoparticles. ZrOCl⦁8HO 수용액을 130℃ 24시간 수열합성 하여 지르코니아 졸을 만들었고 이 후 중화(세척)과 Ti-sol 첨가량을 변수로 첨가하여 900℃에서 2시간 하소 하였다. 제조된 분말을 X-선 회절(XRD)과 SEM(scanning electron microscope)으로 입자 모양과 결정상을 측정 하였고, 25mm×25mm×1mm로 성형 하여 투과율, 입도분석, 밀도, 경도를 측정 하였다. 주 결정상은 정방정상 나노입자가 형성 되었다.

국산 왕겨로부터 알카리 처리한 활성탄의 비표면적에 관한 연구

이학주, 박연경, 김택남 배재대학교 공학연구소 2011 공학논문집 Vol.13 No.1

The activated carbon is widely used for the adsorption materials in the filtering of polluted water and selectively separation of different molecules of gases such as CO2 and CH4. In addition, the anode of super capacitor is mainly made from the activated carbon from pitch or graphite. The rice husk contains organic materials and Si. Thus the remove of silicon is important in the synthesis of activated carbon from rice husk. The contents pf Silicon is normally about 25 wt. % in rice husk and The content of fixed carbon is about 13 wt. %. In this experiment, the rice husk from the domestic product was washed and dried at 110 ℃ for 24 hours. The dried sample was chopped and sieved by 425 mesh with attrition mill for 30 min. with 2 mm zirconia ball at 600 rpm. Firstly the dried and sieved sample was burned out in the atmosphere of N2 (300 ml/min.) at 700 ℃ for 2 hours. The carbonized sample was alkali treated and stirred at the ratio of 1.0, 2.0, 4.0 of KOH/carbon at 60 ℃ with distilled water for paste. This alkali treated sample was heat treated at 700, 800, 900 ℃ for 3 hours at the atmosphere of N2 (300 ml/min.). The samples washed at 100 ℃ for several times and dried 110 ℃ for 24 hours. The final activated carbon was analyzed by XRD, BET and SEM. The amorphous of activated carbon was observed among all the samples wih various KOH content and heating temperatures. The morphology of the activated carbon is not changed so much but the size and distribution will be more uniform with increased heating temperature. With more KOH contents, the pore size of activated carbon was observed more porous structure through samples. The surface area of activated carbon gradually increased with the contents of KOH. However, the maximum value of BET was observed at 1:2 (Carbon:KOH) at 900 ℃ Heat treatment. In the same ways, the BET was increased with increased heat treating temperature.

Synthesis of 3 mol % yttria stabilized zirconia using precipitation and sol-gel method

사신 브람, 김택남 배재대학교 공학연구소 2012 공학논문집 Vol.14 No.1

There is increasing interest in zirconia as a dental material due to its aesthetics. Sol-gel method is considered to be the best for its synthesis. Here we have tried to synthesize zirconia by combining precipitation with sol-gel method. NaOH is the precipitating agent used in this method, which we think, is easy to separate from the final solution. Zirconium and yttrium salts are used as precursors and PEG is used to separate the metal ions. Finally the zirconia powder obtained is calcined at 900oC for 2hrs. XRD analysis was done on the samples to confirm the crystal structure which showed that 1M ZrOCl2 gave the best result.

수열합성 반응에 의한 3mol % 지르코니아 세라믹의 Fe2+, Fe3+, Er3+치환에 따른 상변태와 물성 변화

변지철, 이현철, 김택남, 류재경 배재대학교 공학연구소 2017 공학논문집 Vol.19 No.1

Zirconia is a heat-resistant material with a high melting temperature(2700℃) and has low thermal conductivity and excellent corrosion resistance. However, application has been limited due to brittleness, which is a disadvantage of ceramic materials. As a way to improve this, the addition of Y3+ improves the strength by phase transformation, which can improve the brittle problem, which is a disadvantage of ceramic. Many studies have been conducted on the addition of Y3+ after the addition has been found to be more efficient than the other additives. In this experiment, have studied the additives that replace this Y3+. Expeiments on the possibility of replacing Y3+ by adding an alternative additive considering Zr-sol(Fe2+, Fe3+, Er3+) in consideration of Atomic size, Crystal ionic raddi and Effective Ionic raddi. ZOC(ZrOCl2*8H2O) was dissolved in distilled water and synthesized by hydrothermal synthesis at 160℃ for 24hours. The formed Zr-sol was separated into a supernatant and precipitate. The supernatant was washed with distilled water, and the presence of chloride ion was confirmed using AgNO3. And add to the cleaned Zr-sol an additive that is believed to be a substitute for Y3+. The prepared Zirconia was calcined at 900℃ for 2hours, and the crystal phase was analyzed by XRD similar that of YSZ. The calcined powder was uniaxial pressed and sintered at 1500℃ for 2hours. The sintered specimens were first measured for specific gravity. And the particle size distribution, EDAX and FESEM were measured. 지르코니아는 고온에선 용융하는 (2700℃) 낮은 열전도율과 부식저항이 우수한 세라믹이다. 이에 우수한 파괴인성을 주기 위해 3 mol % Y를 첨가하게 되고, 상온에서 정방정 상으로 존재함으로써 파괴인성이 증가한 것으로 알려져 있다. 따라서 본 실험에서는 Y와 유효 원자 반경이 유사한 Er3+ (89pm)를 첨가함으로써, 과연 어떤 변화가 나타나는지를 알아보았다. 또한 원자가가 유사한 Fe3+와 Fe2+ 를 첨가하여 물성변화와 상변화를 조사하였다. 연구결과 이온 반경이 Y와 유사한 Er3+에서는 완전한 정방정상과 밀도, 투광율 (일부 파장은 제외)을 나타내었으나, 이온 반경이 약1/2 인 Fe2+, Fe3+를 첨가한 경우에는 단사정과 비정질 그리고, 650nm이하의 파장에서는 거의 투광하지 않는 현상을 보였다.