Journal of the Korean Ceramic Society Vol. 48, No. 4, pp. 298~302, 2011. DOI:10.4191/KCERS.2011.48.4.298 Synthesis of Cr-doped Pyrochlore-type Pigments and Coloring in Glazes Hye-Jin Eo and Byung-Ha Lee Department of Material Science & Engineering, Myongji University, YongIn 449-728, Korea (Received June 16, 2011; Resived July 8, 2011; Accepted July 22, 2011) Cr-doped Pyrochlore w x Á w w œw (2011 6 16 ; 2011 7 8 ; 2011 7 22 ) ABSTRACT This study developed a pigment by doping Cr to Pyrochlore-type stannate crystals and investigated the chromogenic relationship in a glaze. Crystal phases of the pigment according to firing temperatures were analyzed by XRD, and the doping relationship was analyzed by Raman Spectroscopy. Color and reflection rate of the pigment were measured by UV-vis Spectrophotometer. Consequently, stannate characteristic band appeared at 307, 408, 505 and 755 cm 1 until 0.1 mole substitution of Cr 2 O 3. However, as amount of Cr 2 O 3 increased, the stannate characteristic peak was decreased and shift happened at the left hand side due to Cr-dope. In composition of 0.12~0.14 mole substituted, the unreacted Cr 2 O 3 stannate characteristic peak, which was not engaged, was shown. This result shows the maximum limit of solid solution was 0.1 mole Cr 2 O 3. The color of the glaze, which was produced by adding 6wt% of Sn 1.94 Cr 0.06 pigment in a lime or a lime-magnesia glaze and fired the mixture at 1260 C, was grayish pink with L* 70.29, a* 5.68 and b* 6.27. It showed gray with L* 68.82, a* 3.07and b* 8.13 for Sn 1.9 Cr 0.1. Key Words : Pigment, Pyrochlore, Stannate, Gray 1. Pyrochlore Structure w fluorite structure super structure q B-site w tetrahedral p w w. A 2 B 2 œ ùkù, A B m. 13) Pyrochlore-type y Ÿ w w š. p, Pyrochlore y, p ƒ ùkù,,, xÿ,. ƒ 6) defect structure x w Pyrochlore A B Site dopant» mw g y w. 6) p, Stannate pyrochlore 40 w š, w, w p, w w ƒ š. 1) Pyrochlore-type stannate Cr š g z w z w. Corresponding author : Byung-Ha Lee E-mail : djenahr@naver.com Tel : +82-31-330-6461 Fax : +82-31-330-6457 2. x 2.1. Pyrochlore-type stannate w w» w Yttrium (III) oxide (junsei, 99.9%), Tin (IV) oxide (Junsei, Chemial pure), Chromium (III) oxide (duksan, 99%) w. Stannate Cr 2 O 3 SnO 2 ey g š w» w Table 1 Cr 2 O 3 ƒ ƒƒ 0.06 mole l 0.12 mole¾ 0.02 mole yw w w. 7) w Table 1 p g š yww z w. Table 1. Compositions of Samples Sample Composition PS6 Sn 1.94 Cr 0.06 PS8 Sn 1.92 Cr 0.08 PS10 Sn 1.9 Cr 0.1 PS12 Sn 1.88 Cr 0.12 PS14 Sn 1.86 Cr 0.14 298
ù ƒ Ë š»ƒ 1300~ 1500 o C¾ 3 o C w z þw. Cr-doped Pyrochlore w 299 2.2. p» w X- z (XRD 7000, Shimadzu) wwš, w stannate Cr š» w Raman spectroscopy (Dimention D2, Lambda Solu tion, Inc, U.S.A) w. Raman spectrum vector raman probe (RP-532-US) w semiconductor 532 nm laser d w spectral resolution 3cm 1 w. x» w SEM (scanning electron microscopy, SS-550, Shimadzu) w š, EDX (Energy Dispersive X-ray Spectroscopy) swš r. w stannate d w limemagnesia w w 6wt% ƒ (Seger formular t )w w xr w. xr» ƒ (Siliconite furnace) 1260 o C 1 w þw.» w UVvis Spectrophotometer (2401-PC) w xr d w š, Seger formular. Fig. 1. XRD patterns of samples fired at 1300~1500 o C/3 h. 0.2172 KNaO 0.5104 CaO 0.4220 Al 2 O 3 3.8362 SiO 2 0.2725 MgO Pigment 6wt% Fig. 2. XRD patterns of samples fired at 1400 o C/3 h. 3. š 3.1. Pyrochlore-stannate w Pyrochlore-stannate w w Sn/Y atomic ratio = 1 w 1300 o C~1500 o C¾ w. XRD Fig. 1 ùkü. 1400 o C l Stannate ùkû, 1300 o C O 3 SnO 2 peak w y w. w Table 1 Cr 2 O 3 0.06~0.14 mole y xw. Fig. 2 1400 o C w XRD w w Cr 2 O 3 ƒ š Stannate š. ù Cr 2 O 3 ƒ 0.12 mole l O 3, SnO 2, Cr 2 O 3 peak 2 û 100 o C w y w x w. 1500 o C w Fig. 3 ùkü. 1400 o C 2 w Stannate ùkû, Cr 2 O 3 ƒ Fig. 3. XRD patterns of samples fired at 1500 o C/3 h. 0.12 mole ey l Cr 2 O 3 ƒ w. 3.2. Chromium z p Fig. 3 1500 o C XRD Cr 2 O 3 ƒ šƒ 2θ 59.098 (622) o 59.109 o (622) d Shift y w. 48«4y(2011)
300 x Á w Cr 2 O 3 ey k Stannate Cr 2 O 3ƒ ƒw 3+ 2θ d y. Cr 4+ 4+ 0.069(Å), Cr 0.55(Å), Sn 0.83(Å) Sn Cr ü Sn q Cr ey ù 2θ f š8,9), d 9) y w. d y v Fig. 4 ùkü. x» w SEM w Fig. 5. Pyrochlore-stannate x Cubic, Cr 2 O 3ƒ 0.06 mole e Fig. 4. d value changes of samples PS, PS-6, PS-8, PS-10, PS-12, PS-14 by XRD. y 590 nm, Cr 2 O 3ƒ 0.10 mole e y 428 nm Cr 2 O 3 ú ù w. Pyrochlore-stannate Cr 2 O 3 š y» w Raman w Fig. 6 ù kü. Raman stannate p 311 cm 1, 409 cm, 509 cm 1 2,12), Cr 2 O 3 1 p 555 cm 1, 625 cm w 1 ùkùš, 407 cm 1, 435 cm w ùkù. 3,4) Fig. 6 Cr 2 O 3ƒ š Stannate p 1 509 cm peak 481.4 cm 1 d Shift. y w Shift Cr doping doping w w ùkù x Stannateü Cr 2 O 3ƒ š. š Cr 2 O 3ƒ 0.12 mole 0.14 mole ey Cr 2 O 3ƒ w 1 555 cm Cr 2 O 3 p ƒ shoulder w y w. Pyrochlore-stannate Cr 2 O 3 š 0.1 mole. Fig. 7 Raman y š 0.1 mole s EDX w ùkü. Pyrochlore-stannate Fig. 5. SEM micrographs of samples fired at 1500 o C/3 h. (a) PS-6, (b) PS-8, and (c) PS-10. Fig. 6. Raman spectroscopy analysis of the synthesized pigments. w wz
Cr-doped Pyrochlore w 301 Fig. 7. EDX mapping analysis of PS-10 sample fired at 1500 o C/3 h. Fig. 8. UV-vis spectra of samples PS fired at 1200 o C/3 h. Fig. 9. Pigment color coordinates in the L*a*b* space depending on different temperatures. w yw š w e e š š s š w. 3.3. Ÿw p Pyrochlore-stannate 3+ Cr w ligand field Theory w 400 510 nm 2 ƒ w. Fig. 8 UV-vis d Tanabe-sugano w stannate ü 3+ƒ Cr š 4 A 2g 4 T 2g, 4 A 2g 4 T 1gƒ w octahedral crystal field w. w 15,16) 370 nm~380 nm ùkù 4 T 1g (F) 4 T 1g (P) w stannate Cr(III) w w ùkù j. 16) Sn w š ey Cr ƒw ƒ w. PS-12 PS-14 stannate Tanabe-sugano diagram 4 A 2g (F) 4 T 2g, 4 A 2g 4 T 1g (F) Cr(III) w ù kù 450 nm ùkù Cr(III) w w ü š Cr(III). w w CIE L*a*b* Fig. 9 ùkü. 4. šy» w Pyrochlore stannate z ƒ. -x Cr x (0.06 X 0.14) x. 1) Stannate Cr š k w 1500 C o 3h w, ey Cr š 0.1 mole%. 2) w SEM x Pyrochlore x xk Cubic, s³ 428 nm Sn Cr ey ƒ û. 3) Cr 0.1 mole% š Lime-magnesia 6% ƒw xw CIE L* 68.82, a* 3.07, b* 8.13 gray w. 48«4y(2011)
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