나노세공 보에마이트의 합성 및 그 특성평가

김호건,김태용,Kim Ho-Kun,Kim Tae-Young 한국분말야금학회 2005 한국분말재료학회지 (KPMI) Vol.12 No.3

Boehmite (AlOOH) powder with uniform pore size and high specific surface area were synthesized via sol-gel method using metal salts, $Al_2(SO_4)_3$ and $NaAlO_2$. During these synthetic process, the effects of the aging time were investigated to determine the optimal synthetic conditions of boehmite. X-ray diffraction, BET, Raman/IR, and scanning electron microscopy techniques were used for the characterization of the powder. Boehmite gel synthesized at the first stage of the experimental procedure transformed to crystalline boehmite phase after aging for 6 hours. The specific surface area of the crystalline boehmite showed a maximum value, $350m^2/g$, at aging time of 72 hours. The pore size of the boehmite increased with increasing aging time and the boehmite with average pore diameter of 3.6 nm was obtained at aging time of 96 hours.

융액법에 의한 전기광학 단결정 육성

김호건 ( Kim Ho-kun ) 한국공업화학회 1990 한국공업화학회 연구논문 초록집 Vol.1990 No.0

특별강연 - 촉매 및 무기공업화학 : 융액법에 의한 전기광학 단결정 육성

김호건 ( Ho Kun Kim ) 한국공업화학회 1990 한국공업화학회 연구논문 초록집 Vol.1990 No.3

균일 침전법에 의한 은 나노 입자 합성

강원모,김호건,Kang, Won-Mo,Kim, Ho-Kun 한국분말야금학회 2008 한국분말재료학회지 (KPMI) Vol.15 No.5

Silver particles were synthesized from silver nitrate by homogeneous precipitation and chemical reduction methods involving the intermediate silver cyanate. The obtained silver particles were characterized by XRD, SEM, TEM, and BET. Urea which could prevent the agglomeration of the reduced silver particles was used as a homogeneous precipitator. The spherical silver particles with average particle diameter of 100 nm were obtained under the optimum reaction conditions. The optimum synthetic conditions were found as follows: reaction temperature $100^{\circ}C$, reaction time 60 min, concentration of silver nitrate $1{\times}10^{-2}$ mol, urea $5{\times}10^{-3}$ mol, and sodium citrate $8.5{\times}10^{-4}$ mol. The phase of obtained silver particles was crystalline state and the silver particles were relatively dense, which had the surface area of $0.7571\;m^{2}/g$.

나노세공 Zirconia의 합성 및 특성평가

우승식,김호건,Woo, Seung-Sik,Kim, Ho-Kun 한국분말야금학회 2007 한국분말재료학회지 (KPMI) Vol.14 No.5

Zirconia powders with nano size pores and high specific surface areas were synthesized via aqueous precipitation and hydrothermal synthetic method using $ZrOCl_28H_2O$ and $NH_4OH$ under pH=11 and ambient condition. By this reaction. zirconia hydrate $(ZrO_x(OH)_{4-2x})$ was primarily synthesized and the obtained zirconia hydrate was heat treated hydrothermally using an autoclave at various temperatures under pH=11. X-ray diffraction, Scanning electron microscopy, Energy dispersive X-ray spectroscopy, FT-IR, Raman, Particle size analysis, DTA-TG, and BET techniques were used for the characterization of the powder. The synthesized zirconia showed an amorphous phase, however, the phase was transformed to the crystalline state during the hydrothermal process. The observed crystalline phase above $160^{\circ}C$ was a mixed phase of monoclinic and tetragonal zirconia. By the BET analysis, it was found that the specific surface area was ranged in $126{\sim}276m^2/g$ and the zirconia had the cylindrical shaped pores with average diameter of $2{\sim}7nm$.

초임계 유체내의 나프탈렌의 용해도

김정림,김호건,경진범,Jeong-Rim Kim,Ho-Kun Kim,Jin-Burm Kyong 대한화학회 1988 대한화학회지 Vol.32 No.4

임계점 이상의 여러 온도와 압력에서 암모니아내의 나프탈렌의 용해도를 측정함으로써 용해도와 암모니아의 밀도 사이의 관계를 간단한 식으로 나타낼 수 있었다. 이 식을 이용하여 더 높은 압력이나 더 낮은 압력에서의 용해도를 계산할 수가 있으며, 이로부터 용해에 수반되는 에너지 변화와 엔트로피변화를 구하고, 초임계 이산화탄소내의 나프탈렌의 용해도 자료로부터 얻어진 결과와 비교하였다. 또한 나프탈렌과 암모니아 사이의 상호작용 비리알 계수를 결정하여 나프탈렌과 이산화탄소 사이의 경우와 비교 검토하였다. The solubilities of naphthalene in ammonia could be measured at various temperatures and pressures above the critical point of ammonia to represent the relationship between the solubility and the density of ammonia at desired temperature and pressure by means of a simple equation. This equation allows a calculation of the solubilities at higher and lower pressures. Using the equation, the solution energies, the solution entropies, and the second cross virial coefficients between naphthalene and ammonia have been determined to be compared with those in the case of the dissolution of naphthalene in supercritical carbon dioxide.

졸-겔법을 이용한 은 담지 하이드록시아파타이트의 제조

문병배,김호건,Mun Byung-Bae,Kim Ho-Kun 한국분말야금학회 2005 한국분말재료학회지 (KPMI) Vol.12 No.6

In the present study, silver-doped antibacterial hydroxyapatites were successfully prepared by the sol-gel method. For the starting solution, the molar ratio of $Ca(NO_3)_2{\cdot}4H_2O, P(OC_2H_5)_3,\;C_2H_5OH,\;and\;H_O$ was set to 0.075:0.045:20:0.135; $AgNO_3$ was added to a ratio of Ag to total cation concentration of $0.5-12 mol\%$. The prepared sol was dried at $100^{\circ}C$ for 48h and heat-treated at $1000^{\circ}C$ for 2h to obtain particles in the 200-500nm size range. The product from the synthesis of silver-doped hydroxyapatite was investigated through X-ray diffraction experiments and scanning electron microscopy. The product showed high antibacterial properties, with a disinfection ratio of Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 25922) over $99.9^{\circ}C$ as calculated from an antimicrobial effects evaluation by the shake flask method.

Flux 법에 의한 합성 에메랄드 단결정 육성

박선민,이철태,김호건 ( Sun Min Park,Chul Tae Lee,Ho Kun Kim ) 한국공업화학회 1996 공업화학 Vol.7 No.1

합성에메랄드[(BeO)₃(Al_(2-x)Cr_xO₃)(SiO₂)_6]단결정을 flux법에 의하여 육성하였다. 출발물질로 BeO, Al₂O₃와 SiO₂ 시약을 화학양론비로 혼합하여 사용하였다. 에메랄드 단결정의 성장 조건은 다음과 같다. 온도범위 ; 1150∼900℃, 냉각속도 ; 2, 4, 10℃/hr, 융제 ; Li₂CO₃,V₂O_5, 첨가제 ; Cr₂O₃. 에메랄드 단결정의 크기는 2, 4, 10℃/hr의 냉각속도에 의존하였다. 얻어진 에메랄드 단결정을 동정하였고, 그 결과는 다음과 같다. 즉, 결정계 ; 육방정계, 격자상수 ; a=0.921㎚, c=0.917㎚, 결정의 크기 ; 최대 0.80×0.95㎟(c×m), 방위 ; c(1000), m(101￣0). Growth of synthetic emerald[(BeO)₃(Al_(2-x)Cr_xO₃)(SiO₂)_6]single crystals was carried out by flux method. In this study, the starting materials were prepared by stoichiometric mixing of BeO, Al₂O₃ and SiO₂ as reaching components. The conditions for the growth of synthetic emerald single crystals are as follows : temperature range ; 1150∼900℃, cooling rate ; 2, 4, 10℃/hr, flux ; Li₂CO₃, V₂O_5, dopant ; Cr₂O₃ The sizes of Cr₂O₃ emerald single crystals depending on 2, 4, 10℃/ hr cooling rates. The obtained emerald single crystal was characterized and the following results were obtained : lattice parameter ; a=0.921㎚, c=0.917㎚, crystal system ; hexagonal, crystal size ; max. 0.80×0.95㎟(c×m), orientation ; c(1000), m(101￣0).

Bi 치환에 따른 $Ca_{1.5-1.5x}Bi_xVO_4$ 조성 화합물의 결정상에 관한 연구

김명섭,박선민,김호건,Kim, Myung Seab,Park, Sun Min,Kim, Ho Kun 대한화학회 1999 대한화학회지 Vol.43 No.5

The phase change upon Bi substitutions in $Ca_{1.5-1.5x}Bi_xVO_4$ has been systematically studied. The x value corresponding to the maximum Bi substitutions reades to 0.14 and in this range($x{\leq}0.14$), the single phasic $Ca_3(VO_4)_2$ can be identified. However, a new phase of $BiV_{1.025}O_{4+x}$ is apparently formed along with the $Ca_3(VO_4)_2$ phase, when the x value exceeds beyond 0.18 ($x{\geq}0.18$). As a result of Bi substitution in the range of x$\leq$0.14, the interplanar space($d_300$) becomes larger as the Bi content increases. Since the composition of single phasic $Ca_{1.29}Bi_{0.14}VO_4$ (x=O.14) is, however, incongruent melting one, no definite melting point could be observed. But we found that its solidus temperature was 1182$^{\circ}C$ by DTA analysis. $Ca_{1.5-1.5x}Bi_xVO_4$계 화합물에 대하여 Bi 치환량(x)에 따른 결정상을 조사한 결과, 치환량이 x=0.14까지 다른 상의 생성없이 단일상으로 존재하였으나, 치환량이 0.18 이상인 경우 새로운 화합물인 $BiV_{1.025}O_{4+x}$가 함께 석출되었다. $BiV_{1.025}O_{4+x}$의 양은 x=0.18인 경우 16%, x=0.22인 경우 21%임이 확인되었다. Bi의 치환량이 0.02인 경우 구조의 변화가 거의 없었으나, 치환량이 0.06∼0.14일 때 치환량에 따른 면간거리(d)의 변화량은 0.01 mole% Bi당 (214)면은 $1.7417{\times}10^{-3}{\AA}$,(300)면은 $1.7417{\times}10^{-3}{\AA}$을 나타내었다. 단일상으로 존재하는 최대 치환량이 x=0.14인 $Ca_{1.29}Bi_{0.14}VO_4$ 조성 화합물은 합치용융조성(congruent melting composition)이 아니며, 이 조성이 용융을 시작하는 고상선 온도(solidus temperature)는 1182$^{\circ}C$임을 알 수있었다.

친수 유리용 TiO2 박막 개발

박진구(Jin Koo Park),김호건(Ho Kun Kim) 한국공업화학회 2002 공업화학 Vol.13 No.1

Titanium n-propoxide [Ti(O^nPr)_4] 및 titanium oxide-acetylacetonate [TiO(acac)_2]를 전구체로 사용하여 친수 특성을 나타내는 TiO_2 코팅 막 제조공정에 적합한 TiO_2 졸 용액을 합성하였다. 합성된 용액은 스프레이 및 딥 코팅법으로 유리 기판 위에 코팅하여 TiO_2 막을 제조하고 그 특성을 평가하였다. 코팅이 형성된 유리 기판 위에 자외선을 조사하면서 물과의 접촉각을 측정한 결과, 자외선 조사에 따라 접촉각이 10˚ 이하로 감소하는 친수 특성을 나타냈으며, 특히 TiO(acac)_2로부터 합성한 졸을 딥 코딩법으로 코팅한 막의 경우 접촉각이 약 8˚까지 급격히 감소하였다. Stable titania sols for the preparation of hydrophilic TiO_2 films were synthesized from titanium n-propoxide [Ti(O^nPr)_4] and titanium oxide-acetylacetonate [TiO(acac)_2]. TiO_2 film were prepared by dipping or spraying the sols on the glass substrates, and the hydrophilic properties of the films were investigated with illumination of UV light. The contact angle of water drop on the films decreased to less than 10˚, revealing the hydrophilic property of the TiO_2 films. For the TiO_2 film prepared by dip coating of the TiO(acac)_2-based sol, the contact angle rapidly decreased to 8˚. This film demonstrated to have an excellent hydrophilicity property.