Journal of the Korean Ceramic Society Vol. 44, No. 8, pp. 451~456, 2007. 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 609-735, Korea *KOPEC Co. Ltd., Kimhae 621-170, 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( ) (2007 7 18 ; 2007 8 7 ) 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 2-58.1SiO 2-16.7B 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 E-mail : bkryu@pusan.ac.kr Tel : +82-51-510-2384 Fax : +82-51-517-8838 w š.» ww 4,5) Frenkel model r (1). ρ() t ρ ---- 0 3γt 1 ---------------- 3 = 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
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 2-58.1SiO 2-16.7B 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 2-58.1SiO 2-16.7B 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. 2.2. 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 10 80 o ¾ d w. r alumina substrate gq r 1cm 1cm ³ w w Archimedes d w (2). w wz
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 2 600 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. 6. 600 o C XRD pattern p vj (3) Fig. 4. TMA curve of 10.5Li 2 O-14.7Al 2-58.1SiO 2-16.7B 2 (wt %) glass. Fig. 5. DTA curve of 10.5Li 2 O-14.7Al 2-58.1SiO 2-16.7B 2 (wt %) glass. Fig. 6. XRD patterns of heat-treated glasses at each temperature. 44«8y(2007)
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. 7 650 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 5 0.040378 0.040378 0.008076 34.07 0.008 Linear 2 0.008333 0.008333 0.004167 17.58 0.022 Square 2 0.030444 0.030444 0.015222 64.22 0.003 Interaction 1 0.0016 0.0016 0.0016 6.75 0.081 Residual Error 3 0.000711 0.000711 0.000237 Total 8 0.041089 S=0.01540 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 5 2153.49 2153.49 430.698 79.35 0.002 Linear 2 294.94 294.94 147.471 27.17 0.012 Square 2 1781.11 1781.11 890.555 164.06 0.001 Interaction 1 77.44 77.44 77.445 14.27 0.033 Residual Error 3 16.28 16.28 5.4285 Total 8 2169.78 S=2.330 R-Sq=99.2% R-Sq (adj) =98.0% w wz
RSM w Li 2 O-Al 2 -SiO 2 (LAS) y w 455 š t (RSM) w. w (3), (4) z. Relative density = 0.935556 + 0.006667x 1 0.036667x 2 0.003333x 1 2 0.123333x 2 2 0.020000x 1 x 2 (4) Transmittance = 45.278 + 2.900x 1 6.383x 2 1.233x 1 2 29.817x 2 2 4.400x 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)
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