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1 Jurnal f the Krean Ceramic Sciety Vl. 43, N. 12, pp. 839~845, Manufacture f High Density Graphite Using Cal Tar Pitch Kwang Yun Ch, Kyung Ja Kim, Dh Hyung Riu, Kwang Hyun Lim,* Jung Il Kim,* In Chel Shin,* Yun S Lim,** and Heyk Jng J*** Divisin f Nan Materials Applicatin, KICET, Seul , Krea *Dai Yang Industrial C., Ichen , Krea **Divisin f Materials Science and Engineering, Myngji University, Yngin , Krea ***Divisin f Plymer Science & Engineering, Chungnam University, Daejen , Krea (Received July 31, 2006; Accepted Nvember 6, 2006) k ve w š Ÿ Á½ Á xá Ÿx*Á½ *Á *Á **Á x ***» ù * ** w œw *** û w š œw ( ; ) ABSTRACT Graphite has hexagnal clsed packing structure with tw bnding characteristics; (1) van der waals bnding between c axis, and (2) cvalent bnding in the a and b axis. The weak van der waals bnds cause self-lubricant prperty, and the strng cvalent bnds cause excellent electric and thermal cnductivity. Furthermre, graphite is chemically very inert because f the material cmpsed f nly carbn elements. Thus, graphite is very useful fr mechanical sealing materials. Hwever, Graphite have prus micrstructure because starting materials f graphite prduce many vlatile during the manufacturing prcesses. This causes lw density f graphite, which is unsuitable fr the mechanical sealing materials. Thus, further impregnatin prcess is generally needed t enhance the graphite density. In this wrk, high density graphite is prepared with the principle f densificatin when cke and pitch binder, prepared frm thermal treatment f cal tar pitch, becme dehydrgenatin during graphitizatin r carbnizatin. Key wrds : Graphite, Mechanical seal, Densificatin, Ckes, Pitch binder 1. ƒ k y w ü w. c w van der waals w, a,b w œ w wš w. w w c w ñ» y» t y š. w w a,b w» ƒ. w p p w» Ÿ w» š. p,» y yw ü, w ƒœ f e ww. f e ƒ Crrespnding authr : Kwang Yun Ch kych@kicet.re.kr Tel : Fax : » w w. w { gj ve yww xw z ky y w ve gj { w»œ ü w» ƒ. š 1) w»œ veweœ z w w w. k gj p w w. ve y» 500 C w w x gj ƒ 2) k š w 500 C { w. 3) w gj ky y w ù» e yƒ. w yw veƒ w» w k y yw w w, w w. ù ky 839

2 840 Ÿ Á½ Á xá ŸxÁ½ Á Á Á x w ³ ù w yw ky» ƒ x š. w ve ky ù x. C-H, C-C w σ e x. 420 KJ/ml ƒ v w. π e σ e w (325 KJ/ ml) w C-H w œ w œ y. acenaphthylene bifluren w 5ƒ š yw w 6ƒ š yw ƒ methylene-phenanthrene k w x w w. w w mw x naphthalene ƒ w w š x w. ü mw ù w w w ky w œ w w w. w w š s š e x ƒ y w ƒ ë. 4) wx š s j» ƒ e x ƒ j ë. w ky d ƒ w. ve mw r x w z ky C š x d x w. k ve 500 C w ky yw w gj w. gj yw CIP x z, y» 1100 C 2200 C ƒ w w. gj (TG), FT-IR mw { ky yw y w C ky z k ky yw w y w š gj k y yw w e y e w,,,, t w y w. 2. x 2.1. gj { š p ù yw( ) k v e w w. k ve p Table 1 ùkü. k ve SUS» Fig. 1» ü w w. gj 5C/min 490, 500 C ƒƒ 60 w w. { z ³ w w w» w 80 rpm. w ù f 240 C 5 w w. 5C/min š 80 rpm. e PID»(SCR unit) w ±1 C w. veƒ œ» w y ƒ w y» w. ve 250 rpm 12 ww 325 mesh(<44 µm) w w. r x gj yww w z 0.1 kg/mm x mm x r w z CIP š 2000 bar xw. x r 5,6) š»w 1C/min w z 1100 C 2 w kyw. kyw r š»w 5 C/ min 2200 C 1 w kyw w w gj Fig. 1. Schematic diagram f cal tar pitch heat treatment reactr. Table 1. Prperties f Cal Tar Pitch Slubility (%) BI TI S. P. ( C) Cking value (%) Specific gravity (g/cm 2 ) Cal tar Pitch BI : Benzene Insluble TI : Tluene Insluble S. P. : Sftening Pint w wz

3 wš, yw w» w ww š w»» Mettler TGA/SDTA851 Thermal Analysis System. 7mg š, š» 25 C l 1200 C¾ 10 C/min w. ky yw r p w» w pin-n-disc type x ww. x r w w, 200 mm, 85 S45C steel disc w. r s w š r ó w ƒ ù w. 600 rpm z w steel disc y(dry cntact) k r š 1~5 kg w r d w w. z t k OLYMPUS OLYMPUS BX51 Optical micrscpe w w. ckes ve ky z e», e», e»»» y w Furier-transfrm IR spectrscpy (Midac, M2000) w IR rp. ky 7) y z r SATO Shre Hardness Tester w d r ƒ w 3z d w z s³ w. 3. š mw gj ve y Fig. 2 ùkü. ƒ ƒw { š. p 510 C g j 1100 C { 0.7 wt% ky Fig. 2. Thermal gravimetry f ckes as a functin f temperature. k ve w š 841 Fig. 3. Thermal gravimetry f pitch binder as a functin f temperature. 99.3%. k ve mw, ky yw w w w w x k g j ƒ. 490 C, 500 C w gj { ƒƒ 6.8 wt%, 3.1 wt% ùküš. gj 300~600 C 600 C š ùkü w š. { w yw ü e ù 6ƒ š w w k y yw. y û w ƒ š e w ky yw q š y w yw ü 6ƒ š w ù w w w ky yw q. k ve w w y Fig. 3 ùkü. 240 C 1 gj { ƒ 58.2 wt% ky 41.8% š 400 C 1 gj { ƒ 36.1 wt% ky 63.9%. 200 C 400~500 C w w. gj x w wš. ve š gj yy û w û w w. Table 1 yw w w xr ƒ œ,, ùkü. 240 C w binder 490, 500, 510 C w gj yw x 510 C w gj x ƒ ƒ š 490 C w gj ƒ x ƒ ƒ û. ƒ gj { š k gj 43«12y(2006)

4 842 Ÿ Á½ Á xá ŸxÁ½ Á Á Á x Table 2. Mechanical Prperties f Samples Sample Frming Carbnizatin Graphitizatin Density (g/cm 3 ) Density (g/cm 3 ) Shrinkage (%) Shre hardness Density (g/cm 3 ) Denstiy (%) Shre hardness 510ckes+240binder ckes+240binder ckes+240binder ckes+400binder ƒ» x ƒ q. k y z xz w 500 C 490 C w gj w r ƒ. 510 C w gj y w r w. š f 490 C w gj w r f. ky ky yw w mw w w ù w š y w. { g j ƒ ky w y ù e yƒ q. { 490 C gj w r 110 ƒ ùkù w y ù w. 510 C w gj { ƒ ky ky yw w w w ù e yƒ q. { w w. y z r ƒw š 490 C w r g/cm ƒ ùkû. k y z 6ƒ š ü w w û k y yw y e w y ù s w w k q. ky z w. s w w w y ƒ û q. 400 C w w r 240 C w w ky 22% w k w ù x w ù wš ky z y z û. w x w jš gj w j w w w ky e yƒ e q. Fig. 4 ky z r š» 5 w y ùkü v C Fig. 4. Thermal gravimetry f samples as a functin f ckes (600 C, Ar, 5 h). yw k (IG11) ù ƒ û gj w r ƒ f š ƒ gj w r ƒ. š 400 C w { w r 240 C w ƒ. gj ky yw w 2 ùkù 600 C ù { w yw 6ƒ š ü w ky yw w 1100 C ky w š û. Fig. 5 ky z r FT-IR v. k (IG11) wš ~3020 cm -CH 3, =CH 2, =CH- ƒ ùkûš ~1440 cm -CH 2 -CO, -CH 2 -N ƒ ùkû. 490 C gj w r vjƒ w ùkûš 500 C gj vj w ùkû. Fig. 4 ùkù v 1100 C ky z r ky yw û. š 2000 C y e wƒ š w w wz

5 석탄계 피치를 이용한 고밀도 흑연 제조 843 과정시 방향족화합물간의 중축합반응을 촉진하여 치밀한 조직을 갖는 흑연결정을 갖도록 한다. Fig. 6은 490 C에서 열처리한 코크스와 240 C에서 열처 리한 바인더를 사용하여 제조한 탄소재와 흑연재의 이동 거리에 따른 하중별 마찰계수를 나타내었다. 탄화 후 시 편의 마찰계수는 마모가 증가함에 따라 마찰계수가 증가 하고 있음을 볼 수 있다. 그리고 하중이 증가할수록 마찰 계수의 증가가 더욱 확연하게 나타났다. 흑연화 후 시편 의 마찰계수는 낮고 안정적인 마찰거동을 보이고 있다. 하중이 증가하여도 마찰계수의 증가 없이 안정적인 마찰 거동을 보이고 있다. 탄화 후 시편은 무정형으로 흑연결 정이 발달하지 않아 자기 윤활성을 나타내지 않아 마찰 계수가 높고 불안정하다. 반면, 흑연화 후 시편은 육각판 상이 겹쳐진 흑연결정이 발달하여 a,b면으로 미끄러지기 쉬워 자기 윤활성을 띠게 된다. 따라서 마찰이 시작되면 낮은 마찰계수를 나타내고 하중이 증가하여도 안정적인 마찰거동을 보이고 있다. Fig. 7은 각 시편의 연마 후 표 Fig. 5. Fig. 6. FT-IR f samples as a functin f ckes. Frictin cefficient f sample as a functin f sliding distance. Fig. 7. Optical micrscpe f sample after wear test. 제 43 권 제 12호(2006)

6 844 Ÿ Á½ Á xá ŸxÁ½ Á Á Á x Ÿwx. ky z t 510 C gj w r gj, gj gj w x gj ƒ. 500 C w gj w r ky z gj, gj gj w. 490 C w gj w r gj, gj gj w» w ù w»œ wš. gj ƒ swwš {» w ky ky yw w w w { ü»œ» q. š k 240 C 400 C w ü»œx j. sw ky yw w» ƒ g j ü w ky yw j. w e y ³ w x» w q. y z, 510 C w gj w r gj, gj gj w ky z k ù. 500, 490 C w gj w r ü»œ. ky z r w ky yw y w w e y q. w ƒ ƒ j y e y» w gj ky yw q. 4. ƒ ƒw gj { š 510 C gj { 0.7 wt% ky 99.3%. 490 C, 500 C w gj { ƒƒ 6.8 wt%, 3.1 wt% ùküš. gj 300~600 C 600 C š ùkü w š. ky y z ƒ û gj w r ƒ. ƒ { sww gj w r w. š ƒ û r f. { gj ƒ k y w y ù e yƒ š ƒ { g j ky w ù e yƒ q. ky z r ƒ û gj w r ƒ fš ƒ gj w r ƒ. š { w r { ƒ. gj { w ew ky z { w rü û w. ky z r 2870~3020 cm 1 -CH 3, =CH 2, =CH- 1400~1440 cm 1 -CH 2 -CO, -CH 2 -N ƒ ùk û. gj {w ky yw ùkü ky z r ky yw û. ky z r ƒ ƒw ƒ ƒwš. š w ƒw ƒƒ y w ùkû. y z r ûš š. w ƒw ƒ š. ky z t ƒ { gj w r gj, gj gj w x gj ƒ š { sww g j w r ky z gj, gj gj w. { ƒ gj w r gj, gj gj w» w ù gj ƒ swwš { w w» œ w. š w ü»œ ƒ j. y z, { sw gj w r ü»œ. ky z r w ky yw y w w e y q. REFERENCES 1. H. J. Chung and Y. S. Lim, Preparatin f Characterizatin f Mesphase Pitches as a Matrix Precursr f Carbn Fiber Reinfrced Carbn Cmpstie(in Krean), J. Kr. Ceram. Sc., 33 [12] (1996). 2. P. D. Matzins, J. W. Patrick, and A. Walker, Cal Tar Pitch as a Matrix Precursr f 2D C/C Cmpsites, Carbn, 34 [5] (1996). 3. H. J. Jung, Y. J. Chung, D. W. Ch, Y. S. Lim, and K. W. Kim, A Study n the Cnditin f Pyrlysis f Cal Tar Pitch t Frm the Meshphase as a Matrix Precursr Carbn/Carbn Cmpsites(in Krean), J. Kr. Ceram. Sc., 34 [9] (1997). 4. Y. S. Lim, H. S. Kim, Y. J. Chung, M. S. Kim, and J. H. w wz

7 k ve w š 845 Kim, Fabricatin f Glassy Carbn frm Furan Resin(in Krean), J. Kr. Ceram. Sc., 38 [7] (2001). 5. S. W. Lee, K. W. Park, and J. K. Oh, Preparatin f Istrpic Carbn with High Density(in Krean), J. Kr. Ceram. Sc., 28 [11] (1991). 6. H. J. J, D. M. Chi, and I. S. Oh, Fabricatin and Characteristics f CFRC Fabricated with Carbn Fiber and Cal Tar Pitch Matrix, J. Kr. Mater. Res., 4 [2] (1994). 7. K. Christ and K. J. Huttinger, Carbn-Fiber Reinfrced Carbn Cmpsites Fabricated with Mes-Phase Pitch, Carbn, 31 [5] (1993). 43«12y(2006)