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1 Journal of the Korean Ceramic Society Vol. 44, No. 8, pp. 451~456, A Study of Sintering Behavior and Crystallization in Li 2 O-Al 2 -SiO 2 (LAS) Glass System by RSM Kyu Ho Lee, Young Seok Kim, Young Joon Jung, Tae Ho KimS Jin Ho Seo,* and Bong Ki Ryu Division of Materials Science and Engineering, Pusan National University, Busan , Korea *KOPEC Co. Ltd., Kimhae , Korea (Received July 18, 2007; Accepted August 7, 2007) RSM w Li 2 O-Al 2 -SiO 2 (LAS) y w ³yÁ½ Á Á½kyÁ y*á» w œw *KOPEC( ) ( ; ) ABSTRACT This paper presents results and observations obtained from a study of sintering behavior and crystallization in Li 2 O-Al 2 -SiO 2 (LAS) Glass by screen printing method. The variable experimental conditions were determined carefully by Thermal-Mechanical Analyzer (TMA), Differential Thermal Analyzer (DTA) for setting the optimum transparent sintering conditions in LAS glass system, 10.5Li 2 O-14.7Al SiO B 2 (wt%), such as glass-ceramics which usually have low crystallization temperatures. Crystallization glasses generated during sintering was observed from diffraction patterns by X-Ray Diffraction (XRD), transmittance by UV-Vis spectrometer. Finally, the optimum sintering condition of LAS glass and the relation between factors and results in several sintering conditions were given by using Response Surface Methodology (RSM). From this study, we confirmed that crystallization interrupted densification during glass powder sintering. Furthermore, we observed that main effect of factors in glass powder sintering with concurrent crystallization depended on experimental conditions from main effects plot by MINTAB-14. Key words : Glass sintering, Crystallization, LAS glass, Screen-printing, Response Surface Analysis 1. w, ü, üyw w y coating, 1) n š w x y w MLCC t y PDP rib š. y q 2,3,11) t w, y PDP rib ƒ t w glass frits w. w e y. w w e y w Frenkel, Mackenzie, Shuttleworth, Kuzinski w y x ƒ Corresponding author : Bong Ki Ryu bkryu@pusan.ac.kr Tel : Fax : w š.» ww 4,5) Frenkel model r (1). ρ() t ρ γt = ρ g 8η( T)r» ρ 0», ρ g, γ t š η(t).» ùkü, log 6.0 poise d š w 13) Vogel Fulcher Tamman (VFT) equation w d ƒ w. 5,6), e y w t w w. e y l»¾ t w y j, w. ƒ e y š w. w yƒ w, w w ùkù. Fig. 1 e y w j ƒ (1) 451

2 452 ³yÁ½ Á Á½kyÁ yá» Fig. 1. Schematic diagram of crystallization interrupting densification. Fig. 3. Schematic diagram of experiment procedure. Fig. 2. Schematic diagram of optimum sintering condition of glass-ceramics. w yw». yƒ w, x w y f w, w w e yƒ š, w n w. w y w 5,6,11) e y y vw» w, Fig. 2 w w. 7-10), w yƒ e w q wš š, y x š 12) t x (Response Surface Methodology) w. 2. x 2.1. r x Fig. 3. Li 2 C, Al 2, SiO 2, B 2 (Aldrich, 99.9%) yw w z 10.5Li 2 O-14.7Al SiO B 2 (wt%) e w. e ƒ» 800 C 30 w w z o 1400 C 3 o Table 1. Thermal Property of 10.5Li 2 O-14.7Al SiO B 2 (wt %) Glass Property Glass transition point (Tg) Deformation point (Td) Crystallization onset temp. (Tx) Crystallization peak temp. (Tp) Value 521 o C 572 o C 683 o C 792 o C g q w. w z, sieve (#300) m g 2:1 yww pastey g. paste d n d w 10 cm 10 cm ù»q»q Ì ƒƒ screen-printingw r w z, Table 1 ùkü ƒƒ ƒ r» w d Glass frits (Glass transition temperature) y (Deformation temperature) 10 C/min o TMA(Shimadzu TMA-60) dw š, y (Crystallization onset temperature) y (Crystallization peak temperature) 10 C/min o DTA(Shimadzu TG/DTA-60) d w. š y r w» w XRD (Rigaku. Cu Kα, 25 KV, 30 ma) 4/min o o o ¾ d w. r alumina substrate gq r 1cm 1cm ³ w w Archimedes d w (2). w wz

3 RSM w Li 2 O-Al 2 -SiO 2 (LAS) y w 453 Table 2. Factors and Levels of Selected Sintering Condition of Glass Frits Factor X 1 (Sintering Temp). X 1 (Sintering Time) Level A 0 A 1 A 2 B 0 B 1 B o C 650 o C 700 o C 60 min 120 min 180 min ρ s ( sample density) Relative density = ρ f ( full sin tered density)» ρ f e y k r, ρ s ƒ r. r n UV- Vis spectrometer(agilent8453) w d 589 nm w. (2) 2.3. Response Surface Methodology (RSM) w yƒ w e y e w m Minitab-14 w sƒw. wù w w yw ³ wš xyw yw w Hinkelmann Kempthorne w (3) z 12) w t w. k 2 Y = β 0 + β i x i + β ij x i + β ij x i x j + ex ( 1, x 2,, x k ) i = 1 k i = 1 k i< j», x i i w ùkü β 0, β i, β ij linear, square, interaction regression coefficient, e error. x i, j š Table 2 w. w t (Surface Ploting), y (Response Optimization) š z (Main Effect Ploting) w š š w. 3. š x w p dw Table 1. Fig. 4 TMA l (Tg), y (Td) Tg= 521 o C, Td = 572 C dw š o Fig. 5 DTA l y (Tp) 792 o C, y (Tx) 683 o C y w. w l screen-printed glass sample Table 2 w. x ƒƒ y w» w XRD pattern dw Fig o C XRD pattern p vj (3) Fig. 4. TMA curve of 10.5Li 2 O-14.7Al SiO B 2 (wt %) glass. Fig. 5. DTA curve of 10.5Li 2 O-14.7Al SiO B 2 (wt %) glass. Fig. 6. XRD patterns of heat-treated glasses at each temperature. 44«8y(2007)

4 454 ³yÁ½ Á Á½kyÁ yá» Fig. 7. Transmittance changes of screen printed glass samples heat treated at different conditions. ù, 700 o C amorphous k ù x LAS β-spodumene(li 2 O-Al 2-4SiO 2 ) vjƒ ùkû. w, x 700 o C y ƒ w l 600 o C, 650 o C w w w» w w y w. x gq r n Fig o C ƒ n ùkü š 700 o C n ƒ. 650 o C¾ ƒ e yƒ ù n ƒ ù, yƒ w n Fig. 8. Density changes of screen printed glass samples heat treated at different conditions. q. w yƒ w n w f 650 o C v»» l y w. Fig. 8 ùkù d 600 o C, 650 o C ¼ ƒ w 700 o C 30» e y w ù ¼ w y w. β- spodumene(li 2 O-Al 2-4SiO 2 ) w ƒ w w q. w ƒ š x ywš ùkü Table 3. Response Surface Regression Analysis of Variance for Relative Density Source DF Seq SS Adj SS Adj MS F P Regression Linear Square Interaction Residual Error Total S= R-Sq=98.3% R-Sq (adj) =95.4% Table 4. Response Surface Regression Analysis of Variance for Transmittance Source DF Seq SS Adj SS Adj MS F P Regression Linear Square Interaction Residual Error Total S=2.330 R-Sq=99.2% R-Sq (adj) =98.0% w wz

5 RSM w Li 2 O-Al 2 -SiO 2 (LAS) y w 455 š t (RSM) w. w (3), (4) z. Relative density = x x x x x 1 x 2 (4) Transmittance = x x x x x 1 x 2 (5)» x 1, x 2 ƒ. w z w Tables 3, 4 ùkû. w P-value 0.05 w ƒ w š w š l R 2 ƒƒ 98.3%, 99.2% ƒ w. ƒƒ t Figs. 9, 10 ùkü. n, 650 o C 3 w ƒ ƒ. yw š z w y w., Fig. 11 ùkù 649 o C 3 y w. š Figs. 9, 10 t ƒ ƒ»» 649 o C w»»ƒ û y w. Fig. 11. Response Optimization for relative density according to time & temperature. Fig. 12. Main Effects Plot for relative density according to time & temperature. Fig. 9. Surface Plot of transmittance according to time & temperature. Fig. 13. Main effects plot for transmittance according to time & temperature. Fig. 10. Surface Plot of relative density according to time & temperature. ƒ w w y w w z ùkü Figs. 12, 13 44«8y(2007)

6 456 ³yÁ½ Á Á½kyÁ yá». v x s³ š ƒ ƒ s³ wš ƒ s³. n e 650 o C w j š, w û. w l w w w š, w w y w. 4. x RSM(Response Surface Methodology) mw, w 10.5Li 2 O-14.7Al SiO B 2 (wt%) w glass frits y e y w w w. RSM mw y w, x glass frits w y e y w ww n j ùkù, x 600 o C ~ 700 o C, 1 ~ 3 h 649 o C, 3 h y. š RSM mw z ùkü, z ƒ, z ƒ y w. w, x glass frits w œ x y y ƒ j w w x w q. Acknowledgement x BK21 w (R ). REFERENCES 1. O. N. Tkacheva, V. E. Gorbatenko, and A. G. Tkachev, New Method for Producing Glass Matrices for Heat-resistant Glass-enamel Coatings, Glass and Ceramics, 47 [6] (1990). 2. H. S. KimG and B. H. Jung, Application of Lead-Glass to Barrier Rib Materials in Plasma Display Panel, Mater. Sci. Forum, (2003). 3. S. F. Wang, C. K. Thomas, W. Huebner Young, and J. P. Chu, Liquid Phase Sintering and Chemical Inhomogeneity in the BaTi ± BaC LiF system, J. Mater. Res., 15 [2] (2000). 4. M. O. Prado, E. D. Zanotto, and R. Muller, Model for Sintering Polydispersed Glass Particles, J. Non-Cryst. Solids, 279 [2] (2001). 5. M. O. PradoGand E. D. Zanotto, Glass Sintering with Concurrent Crystallization, Comptes Rendus Chimie, 5 [11] (2002). 6. M. O. Prado, C. Fredericci, and E. D. Zanotto, Non-isothermal Sintering with Concurrent Crystallization of Polydispersed Soda lime silica Glass Beads, J. Non-Cryst. Solids, 331 [1-3] (2003). 7. G. H. Beall, Design and Properties of Glass-Ceramics, Annu. Rev. Mater. Sci., (1992). 8. C. Siligardi, M. C. D Arrigo, and C. Leonelli, Sintering Behavior of Glass-Ceramic Frits, Am. Ceram. Soc. Bull., 79 [9] (2000). 9. J.-H. Jean and T. K. Gupta, Liquid-phase Sintering in the Glass-cordierite System, J. Mater. Sci., 27 [6] (1992). 10. Y. W. Park and B. X. Hyun, Studies on the Sintering of the Cordierite Glass-ceramic, J. Kor. Ceram. Soc., 29 [10] (1992). 11. Y. W. Jeon, J. M. Cha, D. W. Kim, B. C. Lee, and B. K. Ryu, Crystallization Kinetics by Thermal Analysis on Starting Glass Composition for PDP Rib, J. Kor. Ceram. Soc., 39 [8] (2002). 12. K. Hinkelmann and O. Kempthorne, Introduction to Experimental Design, pp in Design and Analysis of Experiments, vol. 1, John Wiley and Sons, New York, I. Gutzow and J. Schmelzer, The Viscosity of Glass-Forming Melts, The Vitreous State. Thermodynamics, Structure, Rheology and Crystallization, Springer, Berlin, w wz