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1 Korean Chem. Eng. Res., Vol. 43, No. 4, August, 2005, pp 분무열분해공정에의해합성된바륨티타네이트분말의결정화및형태특성 m *, ** Ço i * Ç q ** Ç i *** Çq *** Ç ly ***, * l o q re o q 100 **l ne e 1347 *** ne v k 1 (2005 1o 18p r, o 30p }ˆ) Characteristics of Crystallinity and Morphology of Barium Titanate Particles Prepared by Spray Pyrolysis Kyo Kwang Lee*, **, Kyeong Youl Jung*, Jung Hyun Kim**, Hye Young Koo***, Seo Hee Ju*** and Yun Chan Kang***, *Advanced Materials Division, Korea Research Institute of Chemical Technology, 100, Jang-dong, Yuseong-gu, Daejeon , Korea **Department of Chemical Engineering, Yonsei University, 134, Shinchon-dong, Sodaemoon-gu, Seoul , Korea ***Department of Chemical Engineering, Konkuk University, 1, Hwayang-dong, Gwangjin-gu, Seoul , Korea (Received 18 January 2005; accepted 30 June 2005) k h o ~ p o nkp l rl p Žˆ p ( ) p m. nkl ~ o p s ~ p l rl p p r s ˆ l m p s m. o ~ l, lž lž p ~ nl p l o ~ p s l r l ˆp p llr. nkl l p ~ nl p l p p lv s~ r. nkl ~ l p kp v l llv p r s tkr p p r l r r p p p v m. p l p o nkp p l sp r r r s, p rp r. l rl p p r l p ˆ r. Abstract Barium titanate ( ) particles were prepared by spray pyrolysis from spray solution containing organic additives. The effects of the type and amount of organic precursors on the crystal structure and morphology of the particles were investigated. It was found that the morphology of particles before and after calcination depended on the type of organic additives such as citric acid, ethylene glycol and polyethylene glycol. Among these organic additives, citric acid was the most effective to prepare particles with nano-structured morphology consisting with uniform size nanometer particles after calcination. It was also found that the phase transformability of the metastable cubic phase to the tetragonal one during calcination could be improved by increasing the content of citric acid in the spray solution. As a result, particles prepared from spray solution containing high concentration of citric acid had good tetragonality, uniform and fine size, and high BET surface area after calcination. particles prepared by spray pyrolysis had nanometer size and uniform morphology after simple ball milling process. Key words: Nanoparticle, Barium Titanate, Spray Pyrolysis, Tetragonality 1. or~ (Ferroelectric oxide) m PTCR p q n, l r To whom correspondence should be addressed. yckang@konkuk.ac.kr (MLCC, multilayer ceramic capacitor)p rp r r s v q rsl l v p [1-3]. e k, sp pq m p q o l s-, r, l p k p l v lm [4-6]. r p m nkl rr pe o p 517

2 518 p Ër lë t Ë mët Ë o p, p k p ˆl o l p p qp rs v m p } n. alkoxide v s- p r rml p p lv, p ~ rs v o vp p r e pp p, nkp r sr lk s p., o vp } s l rs p Ba/Ti l m p rs dp l ƒ m p. l l p p p n on p. p p n kp o p vr lp pp, r rp n v k. vp p e, pq, k p r d rl p. l p nkp e krp p s, l p ~ rp kr qp p l p l p krl p pq rs rp l rp scale-upp np qrp v p. kr l nvp e p t lvv kp, q p l l p ˆr p nvp p pl l s rp v p. p pq p sr o l p l v p [7, 8]., l p pq rs o l rr, rk l, m ~ l p p l lv p [9-11]. Kang p n k r q p FEAG(filter expansion aerosol generator)p p rp pn l p k pq rsl rn m [12]., Xia p m ~ l (salt-assisted aerosol decomposition)p n rp pn l p pq m [13]. p n p krp p pq lv p k l p p pq r r l p p llv. l nkl l p o ~ p f p pq p n l rl p rp or~ vp p m. n kl l p ~ p l rl p n ˆ p p. p ˆp pq r p q r p p pq p l p s v. p s v r ~ p rp l srp v p ll. l nkl ~ o p s ~ p llv p r, ˆ l m p m. 2. Fig. 1p l l n l rp e ˆ. p o l rp kr krp mp l vl p l pp p pq v v. kr 1.7 MHz p v l q ln d n m. ln d l n v q krp eˆ k p lp o43 o k Fig. 1. The schematic diagram of ultrasonic spray pyrolysis. v qp Ž kr l qk pl. p m dp nkp m pr oveˆ o l rp v q tol tl. pž k r q l p krp 5µm p p p v k r p. pž kr q l p krp n ~l p mp p n n ~ k pn m. 6 p pž v ql p p krp p o n eˆ o n ~p o p 40 l/min r mp, p p 1,200 mm, n 55 mmp m p n m. pž q l p p krp s,, l r p l p p m 1,000 o C ov m. nkp v l pr p v p ~ l titanium tetraisopropoxide (TTIP, ALDRICH)m BaCO 3 (ALDRICH) ~ l n, o ~ rp m p o l l (CA, JUNSEI), lž (EG, ALDRICH) lž (PEG, ALDRICH) p ~ l rs m. o ~ rp 0l 1M v e. l rl p llv r ~ p m 900 o Cp d r l 3e k e. llv p v p 2mmp v k p n l lˆm l 24e k m. rs p r r s o l Rigaku Model DMAX-33 X- r n l X- r Ž p s m. XRD Scherrer s equationl p rq m. p, ˆ o l Philips p XL30S FEG t p m. p rp N 2 p pn BET(Micromeritics, ASAP 2400) p r m.

3 3. y l rl p p ˆ r p n nkl p pl. Fig. 2 nkl ~ lv o p s l rl p p ˆ l m p ˆ. nk o p ~ nkp l r l p llv p r ~ p 900 o Cl l} l llv p rq v p. l} m 800 o C p l p p r p r s r. l} m 1,000 o C p p mp nl llv p pq qp p pl pq p pvp p l l l} m 900 o C re. nkp llv p p p p v pp p v ˆp p v. p p p llv po l l rn n ~p o p l krp p l p ~ e p w krp p l s pl p. p rp e e tp p s l l rl p p m s v. l o l, l Žˆ p 519 Ž lž p ~ nl pl o ~ p s l ˆp p llr. nkl 0.2 Mp l p ~ nl p p p lv p p p ov p. l lž p ~ n l llv p nkp v p v p. lž p ~ nl pl p v pq p pq p pq p pvp p pl. l rl p llv p l p p pl o ~ l p q r m. l rl p p l pl o ~ r l p l m p k. Fig. 3p nkl ~ lv l p l rl p lv r ~ p ˆl m p ˆ. p m 1,000 o Cl l rl llv r ~ p 0.6p wp ~ e pv XRD l p rp v pl. l p ~ v kp nkp p v ˆp p v p. l p ~ 0.2 M Fig. 2. SEM photographs of particles prepared by spray pyrolysis from different spray solutions. (a) No additive, (b) 0.2 M CA, (c) 0.2 M EG, and (d) 0.2 M PEG. Korean Chem. Eng. Res., Vol. 43, No. 4, August, 2005

4 520 p Ër lë t Ë mët Ë o Fig. 3. SEM photographs of as-prepared particles by spray pyrolysis. (a) No additive, (b) 0.2 M CA, (c) 0.4 M CA, (d) 0.6 M CA, (e) 0.8 M CA, and (f) 1 M CA. p llv p p p p v p l 0.4 M p l llv p n p ˆ v p. nkl ~ lv l p v l p l p m dl p p ˆ v. nk p l p 0.4 M p p p n p ˆ v n kp p p lv p p v p. p o43 o k mp p l p ~ e p n w l r p lvv kk l p p p. Fig. 4 nkl ~ lv l p m 900 o Cp llv p ˆ l m p lt. l rl p llv p r s p r l r r e t o 900 o Cl 3e j l} rp ~. nkl l p ~ v kp n

5 Žˆ p 521 Fig. 4. SEM photographs of calcinated particles calcined at 900 o C for 3h. (a) No additive, (b) 0.2 M CA, (c) 0.4 M CA, (d) 0.6 M CA, (e) 0.8 M CA, (f) 1 M CA. l llv p l p ~ l llv l l p pqp qp pl. l nk l l p ~ l llv p mp l} l p p pq p lv ˆ p v p. p l} p p ˆ l rl p llv r ~ p pl p. l p ~ nkp l rl p r ~ p n kp p ˆ v l m l p r rl pvp p pq p lv p lr. v, l p ~ lp mp l} l llv p pv p pl p pq p v l l rl p p l r. Fig. 5 Fig. 6p nkl ~ lv l p ~ p Korean Chem. Eng. Res., Vol. 43, No. 4, August, 2005

6 522 p Ër lë t Ë mët Ë o Fig. 5. X-ray diffraction spectra of calcinated particles. (a) No additive, (b) 0.2 M CA, (c) 0.4 M CA, (d) 0.6 M CA, (e) 0.8 M CA, (f) 1 M CA. Fig. 6. X-ray diffraction traces of the (200) and (002) reflection for particles. (a) No additive, (b) 0.2 M CA, (c) 0.4 M CA, (d) 0.6 M CA, (e) 0.8 M CA, (f) 1 M CA. p r l m p ˆ. m 900 o C l llv p l p ~ l ~ l p v pp, XRD r q 30l 41 nm p m. v p or l p m p r s p Fig. 6l lv p nkl ~ lv l p p m p ~. p r r p pp X- rž p (002)m (200)p l p [14]. Li p l p p p r r r p pp p n t r (200)p ˆ (002) 3 p l r rp p p o p p ep rk m [14]. α=3π (002) /(3Π (002) +Π (200) ) l α r r p pp, Π (002) Π (200) p (002) (200) r p ˆ. p p p r o43 o k Fig. 7. BET surface areas of the particles. r p pp p m l nkl l p ~ p p v m. nkl ~ lv l p ~ p p rl p m p ~. Fig. 7p l rl p llv p rp ˆ. m 900 o Cl llv p l p ~ p 0p rp p 3.2 m 2 /gp l l p ~ p 1Mp rp 24 m 2 /g v m. l rl p llv p p kk o v k p pn l r l p p m. Fig. 8p nkp ~ l l llv p rq v p. l p ~ v kp nkp llv p 500 nm r p pq 200 nm r p pq p q l p. l nkl l p ~ l rs p r l p v p. v, nkl l p ~ tp rp ~ 150 nmp v p p p lt. 4. nkl l p o ~ r n l rl p MLCC l or~ v np p p rs m. o ~ r ~ v kp nkp l rl p p r l ˆ ˆ l. l nkl ~ lv l p r l p 150 nmp p llv m. l p p rp l p m p ~. nkl l p ~ p v llv p r sl r r p pp v m. l rl p r r p p p k pn kl or~ rnp p.

Žˆ p 523 Fig. 8. SEM photographs of particles after ball milling. (a) No additive, (b) 0.2 M CA, (c) 0.4 M CA, (d) 0.6 M CA, (e) 0.8 M CA, (f) 1 M CA. y 1. Nowotny, J. and Rekas, M., Electro. Ceram.

7 Žˆ p 523 Fig. 8. SEM photographs of particles after ball milling. (a) No additive, (b) 0.2 M CA, (c) 0.4 M CA, (d) 0.6 M CA, (e) 0.8 M CA, (f) 1 M CA. y 1. Nowotny, J. and Rekas, M., Electro. Ceram. Mater.,(1992). 2. Newalkar, B. L., Komarneni, S. and Katsuki, H., Microwave- Hydrothermal Synthesis and Characterization of Barium Titanate Powders, Mater. Res. Bull., 36, (2001). 3. Maison, W., Kleeberg, R., Heimann, R. B. and Phanichphant, S., Phase Content, Tetragonality, and Crystallite Size of Nanocscaled Barium Titanate Synthesized by the Catecholate Process: Effect of Calcination Temperature, J. Eur. Ceram. Soc., 23, (2003). 4. Gijp, S., Emond, M. H. J., Winnubst, A. J. A. and Verweij, H., Preparation of by Homogeneous Precipitation, J. Eur. Ceram. Soc., 19(9), (1999). 5. Shin, H. S. and Lee, B. K., Preparation of Barium Titanate Powders by Oxalate Process, Bull. Kor. Ceram. Soc., 10(2), (1995). 6. Urek, S. and Drofenik, M., The Hydrothermal Synthesis of Korean Chem. Eng. Res., Vol. 43, No. 4, August, 2005

8 524 p Ër lë t Ë mët Ë o Fine Particles from Hydroxide-Alkoxide Precursors, J. Eur. Ceram. Soc., 18(4), (1998). 7. Roh, H. S., Kang, Y. C. and Park, S. B., Morphology and Luminescence of (GdY) 2 O 3 :Eu Particles Prepared by Colloidal Seed- Assisted Spray Pyrolysis, J. Colloid Inter. Sci., 228, (2000). 8. Kim, E. J., Kang, Y. C., Park, H. D. and Ryu, S. K., UV and VUV Characteristics of (YGd) 2 O 3 :Eu Phosphor Particles Prepared by Spray Pyrolysis from Polymeric Precursors, Mater. Res. Bull., 38, (2003). 9. Lenggoro, I. W., Okuyama, K., De la Mora, J. F. and Tohge, N., Preparation of ZnS Nanoparticles by Electrospray Pyrolysis, J. Aerosol Sci., 31(1), (2000). 10. Lenggoro, I. W., Itoh, Y., Iida, N. and Okuyama, K., Control of Size and Morphology in NiO Particles Prepared by a Low-Pressure Spray Pyrolysis, Mater. Rese. Bull., 38(14), (2003). 11. Itoh, Y., Lenggoro, I. W., Okuyama, K., Madler, L. and Pratsinis, S. E., Size Tunable Synthesis of Highly Nanoparticles Using Salt-Assisted Spray Pyrolysis, J. Nano. Res., 5, (2003). 12. Kang Y. C. and Park, S. B., A High-Volume Spray Aerosol Generator Producing Small Droplets for Low Pressure Application, J. Aerosol Sci., 26, (1995). 13. Xia, B., Lenggoro, I. W. and Okuyama, K., Novel Route to Nanoparticle Synthesis by Salt-Assisted Aerosol Decomposition, Adv. Mater., 13, (2001). 14. Li, C., Chen, Z., Cui, D., Zhu, Y., Lu, H., Dong, C., Wu, F. and Chen, H., Phase Transition Behavior of Thin Films Using High-temperature X-ray Diffraction, J. Appl. Phys., 86, (1999). o43 o k

43(5)-11.fm

43(5)-11.fm Krean Chem. Eng. Res., Vl. 43, N. 5, Octber, 2005, pp. 616-620 기상공정에의한구형형상의헥사알루미네이트계형광체제조 Ç Ç içq Ç ly 143-701 ne v k 1 (2005 5 2p r, 2005 9 7p }ˆ) Preparatin f Hexaaluminate Phsphr Particles with Spherical