솔-젤 工程을 利用하여 製造된 YAG(Y₃Al5O12) 분말 입형제어
Control of YAG(Y₃Al5O12) Particle Shape prepared by Sol-Gel Process
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초록
본 연구에서 적용한 솔-젤 공정은 반응 초기에 금속 이온들과 구연산의 킬레이트화 반응에 의하여 진행되었다. 솔-젤과 열처리 과정을 거쳐 얻은 젤 분말의 열분석 결과, YAG를 얻기 위한 젤 분말의 소성온도는 900˚C 이상 되어야 하며 소성온도가 증가함에 따라 생성되는 YAG의 결정도가 향상되었다. 솔-젤 반응 시 구연산을 사용하여 얻은 젤 분말을 소성시켜 얻은 YAG는 불규칙한 다공성 구조를 가진 조각들로 구성되었으며, YAG 입자크기 조절을 위하여 유기첨가물의 영향을 고찰하였다. 유기산 보조제인 에틸렌글리콜은 솔-젤 반응 초기에 구연산과 중합반응을 통하여 그물 망상구조를 형성하여 용액 내 금속이온들의 반응영역을 효과적으로 분리시켜 YAG를 미세화 시켰으며, 계면활성제인 Igepal 630은 에멀젼에 의한 용액 내 방울(droplet)을 형성하여 YAG 응집체를 구성하는 입자들의 크기를 증가시켰다. 그러나 YAG 형태는 크게 개선되지 않았기 때문에 젤 분말로부터 균일한 YAG를 제조하기 위하여, 응집체 크기 감소와 균질 크기를 갖도록 젤 분말을 건식분쇄 하였다. 이러한 결과로부터 솔-젤 반응을 거쳐 얻은 젤 분말을 소성 전에 분쇄하는 것은 최종 YAG 산화물의 입도제어에 아주 중요한 공정임을 알 수 있었다.
Abstract
Sol-gel process applied in this study was carried out by chelation of metal ions and citric acid. From the results of thermal gravimetric analysis and XRD analysis of gel powder obtained through sol-gel and heat treatment, gel powders are mostly amorphous, and crystallize completely at 900˚C, and the crystalline structure of YAG increases with increasing calcinations temperature. Since YAG prepared by sol-gel & calcinations process was porous, and the sape and size was irregular and non-uniform, the shape and size of YAG powder had to be controlled. Therefore the effects of organic materials such as ethylene glycol and surfactant on the crystalline structure of YAG powder were investigated. Polyesterification of ethylene glycol and citric acid separated reaction area of metal ions in the solution and decreased the size of YAG primary particles. The addition of Igepal 630 as surfactant formed the droplet in the solution, and increased the size of primary particles which forms the aggregate of YAG. In order to obtain monodispersed YAG particles of uniform size, gel powder prepared with organic materials had to be milled before calcination. And milling process was very important for obtaining YAG of uniform size.
참고문헌 (11)
- Zhang, J. J., "Stunthesis of ultrafie YAG:Tb phsphor by ntrate-citrate sol-gel combustion process", Materials Research Bulletin, 38, pp.1249~1256 (2003)
- Robertson, J. M., "Epitaxially grown monocrystalline garnet cathode-ray tube phosphor screens", Appl. Phys. Lett, 37(5), pp.471~472 (1980)
- Hoghooghi, B., "Synthesis of YAG:Cr phosphors by precipitation from aluminum and yttrium sulfate solutions", Mater. Chem. Phys, 38, pp.175~180 (1994)
- Welker, T., "Recent developments on phosphors for fluorescent lamps and cathode-ray tubes", J. Lumin, 48, pp.49 (1991), 49~56
- van der Weg, W. F., "Saturation effects of cathodoluminescence in rare-earth activated epitaxial Y3Al5O12 layers", Appl. Phys. Lett, 38(9), pp.705~707 (1981)
- Choe, J. Y., "Cathodoluminescence study of novel sol–gel derived Y3-xAl5O12:Tbx phosphors", J. Lumin, 93, pp.119~128 (2001)
- Yang, W., "Synthesis of Nd2O3 Nano Powders by Sol-Gel Auto-Combustion and their Catalytic Esterification Activity", Materials Chemistry and Physics, 84(1), pp.52~57 (2004)
- Hsu, W. T., "Synthesis and luminescent properties of nano-sized Y3Al5O12:Eu³ phosphors", Materials Science and Engineering, B104, pp.40~44 (2003)
- Pechini, M. P., "Method of preparing lead and alkaline earth titanates and niobate and coating method using the same to form a capacitor", US Patent-3,330,697, ~ (1967)
- Christel, L.-R., "Synthesis of YSZ powders by the sol-gel method: surfactant effects on the mirphology", Solid State Sciences, 4, pp.1053~1059 (2002)
- Process Development for the Preparation of Raw and Functional Materials for IT Industries by High Grade Purification of Rare Earth Elements, "Kim, J. S.", Technical Report, MOICE, ~, pp.2003-R-ME11-P- 01-1-1-000 (2006)