Jurnal f the Krean Ceramic Sciety Vl. 44, N. 7, pp. 393~402, 2007. Dense Plycrystalline SiC Fiber Derived frm Aluminum-dped Plycarbsilane by One-Pt Synthesis Dng-Geun Shin, Eun-Bae Kng, Dh-Hyung Riu, Yunghee Kim,* Hng-Sik Park,** and Hyun-Ee Kim*** Nan Materials Team, KICET (Krea Institute f Ceramic Engineering and Technlgy), Seul 153-801, Krea *Ec Materials Team, KICET (Krea Institute f Ceramic Engineering and Technlgy), Seul 153-801, Krea **DACC C. Ltd, Gyengsannam-d 641-120, Krea ***Schl f Materials Science Engineering, Seul Natinal University, Seul, 151-742, Krea (Received July 11, 2007; Accepted July 18, 2007) One-Pt w œ Aluminium dping s e l e w y ky³ Áœ Á x Á½ *Á y **Á½x *** ( )» ù q * ( )» y q ** z j *** w œw (2007 7 11 ; 2007 7 18 ) ABSTRACT Plyalumincarbsilane was synthesized by direct reactin f plydimethylsilane with aluminum(iii)-acetylacetnate in the presence f zelite catalyst. A fractin f higher mlecular weight plycarbsilane was frmed due t the binding f aluminium acetylacetnate radicals with the plycarbsilane backbne. Small amunt f Si-O-Si bnd was bserved in the as-prepared plyalumincarbsilane as the result. Plyalumincarbsilane fiber was btained thrugh a melt spinning and was pyrlyzed and sintered int SiC fiber frm 1200 ~ 2000 C under a cntrlled atmsphere. The nucleatin and grwth f β-sic grains between 1400-1600 C are accmpanied with nan pres frmatin and residual carbn generatin. Abve 1800 C, SiC fiber culd be sintered t give a fully crystallized β-sic with sme α-sic. Key wrds : Plyalumincarbsilane, SiC fiber, Sintering, Sintering additive 1. ky³ š yw w wœ,, w w w. ky³ œ w p wš»y ƒ û 2100 C 1, 4) e yƒ ƒ w. 1973 Prchazka, k w e w ky³ šw ky³ e, 2), 3) k 4) w y, y 5-7) 8) ƒ w w ƒ š. Hnda ky³ ü š 9) Crrespnding authr : Dh-Hyung Riu E-mail : dhriu15@kicet.re.kr Tel : +82-2-3282-2497 Fax : +82-2-3282-7769 y ƒ g e y w wr, y w w ky³ ƒ, w ƒ 2 š w, 1900 C 1% w p w š šw. y ù y ƒw x ƒ j û. ky³ 10) w ù, 5) p, 6,11) 7). wr, w j» w β α k sqx ¼ w ƒ x p w, ƒw 1700~1900 C w z w œ š. 12) ky³ w š, Chi AlN 13) Sc 2 O 3 ƒw (IGP) e w ky 393
394 Áœ Á xá½ Á y Á½x ³ w. ky³ w. s e vw y, 14-21) Ishikawa 15,16,18) vw s e w z š w 500 nm j» y Tyrann-SA w. Dw Crning pk ƒ w l Sylramic ky ³ w. s e 14,17) vw w s e yw ƒw ww Ube Industries p xy w. w» w s 18) p l s e y» s e (PSCS) w w z ww yw j œ š SiC w. 19,20) v s e (s e ) tw-step œ w» œ y w s p l s e w w kw. 21,24) s p s e yw vw ³ w ƒƒ ƒ wš p w ky³ w» w. 1200~2000 C š w y w. p, 1800 C w,» œ x w e y š w. 2. x s p (plydimethylsilane) Wurtz w w w.» 22) 10 l 6 v j 3 l m 530 g Na z 110 C¾ ƒ w 1.3 l p j 8 wwš 8 w. w óù z k Na wš k š m w NaCl ppm w w œ» w w w s p w. 23-25) s p Al-acac(Al(III)- acetylacetnate) p ƒƒ 5% 1 % ƒw š š» š 350 C 400 C 2 g (Fig. 1). Al-acac» Fig. 1. Schematic diagram f 2 step prcess fr plyalumincarbsilane synthesis. w ƒ w» vw ƒw. w œ s e y s p Al-acac w s e One-Pt reactin š w. 21,24) w y œ 350 C 10~20 w y s e w» ww w» w 400 C w 15 ww. w (plydispersity)ƒ j s š, š y p yw., œ w w z, 250 C œ» p 1 w s e wš 400 C» 5 ~15 ww š s e w. FT-IR(FT/IR-460 Plus, JASCO C., Japan), GPC (Waters 2414, Ireland) š 29 Si MAS NMR(Varian Unity Inva 200 MHz sectrmeter, USA) s e,, wp w. Melting Pint d e (BI9100, Bamstead/ Elecrthermal, UK) TGA(TGA/ SDTA 851 e, Mettler, USA) w s e w w. w s e»x» wš œ w (260 C)¾ w 3 w z w. w 0.5 m «w 15 cm z w. z 200 C» 1 yw. y wš w» ù y z w š 60 MPa. y w» ƒ w š w wz
One-Pt w œ Aluminium dping s e l e w y ky³ 395 Fig. 2. Sintering schedule fr the fabricatin f dense SiC fiber. œ w 1200 ~ 2000 C w w. f Fig. 2. 10 C/min w 1600 C¾ Ar» w z 1600 C N 2 +5% H 2» 1 w z Ar» yw 1800 ~ 2000 C¾ š w. ƒ w FE-SEM(JSM-6700F, JEOL, Japan) mw w XRD(D/ MAX-2500/PC, Rigaku, Japan), TGA(TGA/SDTA 851 e, Mettler, USA) w š SiC p sƒw. 3. 3.1. s e w Fig. 3 s e w s p Al-acac FT-IR rp y w. Fig. 3(a) s p r p. 736 cm 1 828 cm 1 Si-CH 3 bending, 1242 1 cm Si-CH 3 stretching w vjƒ ùkû. Fig. 3(b) Al-acac rp 1 600~1600 cm fm vj w ùkû. Fig. 3(c) Fig. 3(d) w ƒƒ s e 25) s e rp 1 2100 cm Si-H stretching w vj 1 1242 cm Si-CH 3 stretching w vjƒ p ùkû. Fig. 3(c) w Fig. 3(d) Si-H stretching vj ƒ. w Fig. 1 3(d) s e 1300~1500 cm w vj Al-acac fm l vj ew y w, s p s e y Al-acac ƒ Si-H ey w Al-acacƒ w s e y q. Al-acac 3 fm w š, w wù fm k œ w d. 19) Fig. 4 s e (a) s e (b) w 29 Si-NMR š. chemical shiftƒ 0.135 ppm 17.07 ppm ƒƒ SiC 4 SiC 3 H w w vj., SiC 4 / SiC 3 H d w s e w. 25). Hasegawa s e 27) massive w q x w, SiC 4 ü ùkù w xk š, SiC 3 H t ù kù w xk., SiC 4 /SiC 3 H ƒ j j s e ù t SiC 3 H w ƒ yw ey SiC 3 H w ƒ. chemical shift- 38.2 ppm ùkù Si-Si vj w s Fig. 3. FT-IR spectra f (a) plydimethylsilane, (b) Al(III)- acetylacetnate, (c) plycarbsilane, and (d) plyalumincarbsilane. Fig. 4. 29 Si MAS NMR spectrum f plyalumincarbsilane. 44«7y(2007)
396 Áœ Á xá½ Á y Á½x Fig. 5. GPC chrmatgrams f (a) plycarbsilane and (b) plyalumincarbsilane. p ƒ s e y ùkú, Fig. 5 e vjƒ ùkù 8.0 ppm Si- O-Si w vjƒ ùkù. y Si-Si w ü w w Si-O-Si w ë ùkù dw, w w Al-acac w w fm l œ š q. w s e s s e 25) w» w GPC ww Fig. 5 ùkü. GPC w j yw vj d s ùkü. Fig. 5(a) s e GPC š 20~27.5 vj, Fig. 5(b) ùkü s e GPC š vj s Fig. 5(a) j ƒ. s s e ù 20 y w vj j x w. š Al-acacƒ t sw SiC 3 H w ey w ƒ w w Fig. 4 NMR l. Al-acac s e w Fig. 6 ƒ xk., w s e x š» Al-acacƒ s e t Si-H w ey Al-acacƒ x s e ƒ w w š w. fm š w s e w. 28 ùkù vj THF» w w vj. Fig. 7(a) s e 1000 C¾ 10 C/min w y ùkü. s e w w š, 200 C s ƒ û 350 ~ 800 C¾ ƒ û. 800 C yƒ 1000 C 60% Fig. 6. Schematics f plyalumincarbsilane synthesis mechanism. w wz
One-Pt w œ Aluminium dping s e l e w y ky³ 397 Fig. 7. TG analysis f (a) plyalumincarbsilane, (b) Al(III)- acetylacetnate under N 2 atmsphere and (c) DTG curve f (a).. Fig. 7(c) DTG š w ƒƒ 200, 360, 460, 540 š 660 C y vjƒ ùk ù, ƒ ƒ s e wƒ û š. s e š w CH 4, H 2ƒ w ƒƒ 550, 650 C w. 25,26) w, û j C 2 H 6 sww yw (CH 3 ) 3 SiH, (CH 3 ) 2 SiH 2 wì w 26-29). 350 C y vj / š w w. wr, 200 C Fig. 7(b) ùkü Al-acacƒ w» w ew w ey v Alacac fm w/ ƒ. 3.2. s e w œ s e 200 C»y 1 y w. ƒƒ 1400, 1600, 1800 C š 2000 C w ky³ w. k z w 1600 C N 2 +5% H 2» 1 w sw w. 30) Fig. 8 ƒƒ 1400, 1800 š 2000 C w ky³ XRD d w. 1400 C 35 β-sic p vjƒ ù kù (Fig. 8(a)), ù SiC ƒ x dw. Fig. 8(b) 1800 C 35, 60, 72 β-sic vjƒ j ùkû, 33 α-sic p vj. l 1800 C β-sic β-sic α-sic ƒ. w α-sic x Tyrann-SA ùkùš, Ca 31) Li 32) 1800 C Fig. 8. XRD patterns f SiC fiber sintered at (a) 1400 C, (b) 1800 C and (c) 2000 C. w SiAlC SiCO XRD vj w vw w vw α-sic x š šw. Fig. 8(c) 2000 C w XRD p v j ƒ w š vj s dw. SiO 2 k vj. Fig. 9 s e š w ky³ w x. Fig. 9(a) 1400 C q ñwš e w q ƒ š, Fig. 9(b) Fig. 9. Crss-sectin image f SiC fiber sintered at (a) 1400 C, (b) 1600 C, (c) 1800 C, and (b) 2000 C. 44«7y(2007)
398 Áœ Á xá½ Á y Á½x Fig. 9(c)»œ w. wr, Fig. 9(c) Fig. 9(b) w x, w w w»œ œ e š e y /» w. SiOC 2.0, SiC 3.0 š w 30%, Fig. 9(b) Fig. 9(c) w ew. Fig. 9(d) e wš ü»œ SiC q š. t ¼ w»œ s e w ü w»sƒ Fig. 10. Crss-sectin and surface images f SiC fibers sintered at 1400 (a,b), 1600 (c,d), 1800 (e,f), and 2000 C (f,g) : a,c,e,g are crss-sectins and b,d,f,h are surface images f the SiC fiber. y t ¼ w»œ x. Fig. 10 ƒƒ 1400 C, 1600 C, 1800 C š 2000 C q t w. 1400 C (Fig. 10(a)) t (Fig. 10(b)) ñwš»œ. w x Fig. 8 XRD ù β- SiC ƒ ³ w x ƒ š. 1600 C w ü Fig. 10(c)»œ š j» ù l w. w ù»œ j» β-sic j» 1400 ~ 1600 C β-sic wx, š SiOC w x, ù»œ ù β- SiC j» ³ w w z w w w ƒ. ƒ g 1800 Cƒ SiC»œ j» ƒ ù»œ x w ƒ. 1600 C (Fig. 10(c)) w β- SiC ƒ f ƒw ù ù j w ù»œ. t e w ùkü. 2000 C w 1800 C w»œ e w ùkü. w. w s e w œ β-sic wx, š w Ì ù»œ x y w ƒ. 1400 C SiCO ƒ š Fig. 10(c) 1600 C» w ƒ ƒ y ƒ š w CO (g) wì ü w k CH 4 (g) xk w w w. w 33) 1600 C ü ky³ wì ù»œ û. 1800 C œ w컜 m w e y w 2000 C (Fig. 10(g)) ü»œ e w. ky³ j» 100~500 nm 1µm w. 2000 C w EDS 36 wt% C 63 wt% Si(C/Si =1.3) š 0.4~0.9 wt% ü d. w, Fig. w wz
One-Pt w œ Aluminium dping s e l e w y ky³ 399 8 XRD ü SiC k ƒ w. 2000 C w w / w w e y v ƒ. Fig. 11(a-d) ƒ ƒ 1800 C 1 (Fig. 11(a)) 1 (Fig. 4 (Fig. 11(b)) w 1850 C 11(c)) š 1900 C 1 (Fig. 11(d)) w q w. 1800 C, 1 (Fig. 11(a)) ù l w ky³ w. w ƒ ((a) (c) (d)) ky³ wì 1900 C 2000 C., 1800 C 4 ¼ w ((a) (b)) ky³ j ù ù j l j w. w SiC ƒ j SiC e y» w. Ishikawa š 15,16,18) w Tyrann-SA 1500 ~ 1700 C CO ƒ ùš 1800 C e yƒ, ky³ ü š y ƒ g e y j y w e š w. ù (a) (c) 9) (d) p j x y ƒ yw y q. SiC y ù k ƒ ƒ w, ü 4) w k ƒ j l w y ƒ. Fig. 11(e-h) e yƒ t l š. (e) (g) (h) ü e y w j ù 1900 C j»ƒ 1µm ƒ w 2000 C j ƒ. (e) (f) 1800 C 4 ¼ w w ù w e y w. Fig. 12 1800 C 1 w š Fig. 11. FE-SEM images f fracture surface f SiC fiber sintered at 1800 C, 1 h (a,e), 1800 C, 4 h (b,f), 1850 C, 1 h (c,g), and 1900 C, 1 h (d,h) : a,b,c,d are interir regins and b,d,f,h are surface regins. Fig. 12. HR-TEM image f SiC fiber sintered at 1800 C, 1 h: (a) tw β-sic nan-crystal flded, (b) stacking fault cmpsed f twins, and (c) amrphus layer f extra free carbn. 44«7y(2007)
400 Áœ Á xá½ Á y Á½x Fig. 13. Schematic mdel f nanpre and SiC nancrystal frmatin during the high temperature pyrlysis f plycarbsilane derived SiC fiber (a) Pyrlysis stage and (b) Sintering stage. w n x. 30 ~ 40 nm j» ky³ š. ky³ d w š. j» š w j l. k 1~2 nm xk w, w k y y w e q. Fig. 13 ky³ w š ü w»œx ùkü. š w (Fig. 13(a)) (Fig. 13(b)) ù ƒ w. Fig. 13(a) 1200 ~ 1600 C w. 1200 C z SiCO» l ky³ w ù ƒ 1400 Cƒ w» k w f š CO (g) SiO (g) xk»y 1600 C ù»œ x wì œ. 23,34) 1600 C w»»y š ù l w ky³ ù»œ û, w t k ƒ w. x ù»œ ù j» s ³ z œ e y j w e. w wz
One-Pt w œ Aluminium dping s e l e w y ky³ 401»» eyw ü k w k Si/C stichimetry ƒ w. 30,33) Fig. 13(b) w SiC. 1600 C ù SiC ù»œ ³ w š k 1800 C š yƒ ùš, e yƒ w. 1600 C k w wš š ³ w SiC ù ù»œ š ³ w e y ƒ. w œ k ƒ (Al, B) w w ƒ ƒ v w. 4. p œ mw s p Al(III)- acetylacetnate j One-Pt reactin m w v s e w w š š w y SiC w. s p e y Al-acacƒ s e t w SiC 3 H ey ww s e x w s e Si- O-Si w. 1600 C SiOC SiO (g), CO (g) w ü ù»œ ƒ ù k ƒ w ƒ 1800 C š œ mw e y. ky³ ù j l š w k ƒ e y» w q. 1900 C œ mw e wš y SiC w ù ky³ 500 nm w 1µm w. y ky³ š ü y p j w š l w ƒ. w w œ w e w ³ w ù w ƒ v w. Acknwledgment» (GNT 02002-5)» (GRT 07048-1). REFERENCES 1. S. Prchazka, The Rle f Brn and Carbn in the Sintering f Silicn Carbide, in Special Ceramics 6 British Ceram. Research Assciatin, 171-81 (1975). 2. H. Suzuki and T. Hase, Brn Transprt and Change f Lattice Parameter during Sintering f β-sic, J. Am. Ceram. Sc., 63 [5-6] 349-50 (1980). 3. W. Bcker, H. Landfermann, and H. Hausner, Sintering f α-sic with Additins f Aluminum, Pwder metall. Int., 10 [2] 87-9 (1978). 4. S. Prchazka and R. M. Scanlan, Effect f Brn and Carbn n Sintering f SiC, J. Am. Ceram. Sc., 58 [1-2] 72 (1975). 5. M. A. Mulla and V. D. Krastic, Pressureless Sintering f β- SiC with Al 2 O 3 Additins, J. Mater. Sci., 29 5321-26 (1994). 6. K. Negita, Effective Sintering Aids fr Silicn Carbide Ceramics Reactivities f Silicn Carbide with Varius Additves, J. Am. Ceram. Sc., 69 [13] C308-10 (1986). 7. D. Fster and D. P. Tmpsn, The Use f MgO as a Densificatin Aid fr α-sic, J. Eur. Ceram. Sc., 19 2823-31 (1999). 8. J. K. Lee, H. Tanaka, and H. Kim, Frmatin f Slidslutins between SiC and AlN during Liquid-phase Sintering, Mater. Lett., 29 1-6 (1996). 9. S. Hnda, T. Nagan, K. Kanek, and H. Kdama, Cmpressive Defrmatin Behavir f Al-dped β-sic at Elevated Temperature, J. Eur. Ceram. Sc., 22 979-85 (2002). 10. R. AUGAlliegr, L. BUGCffin, and J. RUGTinklepaugh, Pressure-Sintered Silicn Carbide, J. Am. Ceram. Sc., 39 386-89 (1956). 11. A. K. Samanta, K. K. Dhargupta, and S. Ghatak, Decm- Psitin Reactins in the SiC-Al-Y-O System during Gas Pressure Sintering, Ceram, Int., 27 123-33 (2001). 12. W. J. Mberlychan, J. J. Ca, and L. C. De Jnghe, The Rles f Amrphus Grain Bundaries and the β-α Transfrmatin in Tughening SiC, Acta. Mater., 46 [5] 1625-35 (1998). 13. H. J. Chi, Y. W. Kim, M. Mitm, T. Nishimura, J. H. Lee, and D. Y. Kim, Intergranular Glassy Phase Free SiC Ceramics Retains Strength at 1500 C, Scripta Mater., 50 1203-07 (2004). 14. A. R. Bunsell and M. H. Berger, Fine Diameter Ceramic Fibers, J. Eurp. Ceram. Sc., 20 284-87 (1995). 15. T. Ishikawa, Y. Khtku, K. Kumagawa, T. Yamamura, and T. Nagasawa, High-Strength Alkali-Resistant Sintered SiC Fiber Stable t 2,200 C, Nature, 391 773-75 (1998). 16. T. Ishikawa, Advances in Inrganic Fibers, Adv. Plym. Sci., 178 109-44 (2005). 17. D. C. Deleeuw, J. Lipwitz, and P. P. Lu, Preparatin f Substantially Plycrystalline Silicn Carbide Fibers frm Plycarbsilane, US Patent N. 5,071,600 (1991). 44«7y(2007)
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