Effect of Processing Parameters on the Densification of Carbon/Carbon Composite by Isothermal Low-Pressure Chemical Vapor Infiltration

등온 저압화학기상침투법에 의한 탄소/탄소 복합재료의 치밀화에 대한 제조공정변수의 영향

  • Park, H.D. (Korea Research Institute of Chemical Technology) ;
  • Ahn, C.W. (Korea Advanced Institute of Science and Technology) ;
  • Cho, K. (Korea Advanced Institute of Science and Technology) ;
  • Yoon, B.Y. (Agency for Defense Development) ;
  • Kim, K.S. (Daewoo Heavy Industries LTD.)
  • Published : 1994.05.01

Abstract

The effect of processing parameters, temperature, gas concentration, gas flow rate and pressure, were studied on the densification of carbon/carbon composites using a Robust design method in isothermal low-pressure chemical vapor infiltration with a gas system of $C_3H_8-N_2$ After one time of isothermal low-pressure chemical vapor infiltrat.ion, the bulk density of carbon/carbon composites in creased up to 1-9% and apparent porosity of the composites decreased down to 20-50%. ANOVA analysis of the experiment.al data revealed that the important parameters of isothermal lowpressure chemical vapor infiltration were temperature, gas concentration and gas flnw rate. 'There was almost no ~ f f e c t on densification by pressure and interaction between each parameters. In t, he present experimental conditions, the highest bulk density was obtained at $1100^{\circ}C$ temperature, 100% $C_3H_8$, concentration, 100 SCCM flow rate and 5 torr pressure.

프로판($C_3H_8$)을 반응가스로 사용하여 등온 저압화학기상침투법(low-pressure chemical vapor infiltration)으로 탄소/탄소 복합재료를 치밀화 할 때 반응온도, 반응가스농도, 가스유량, 반응압력 등의 제조공정변수들이 치밀화에 미치는 영향을 알아보기 위하여 실험계획법(Rdbust design method)에 의한 실험을 행하였다. 1회의 등온 저압화학기상침투 실험으로 탄소/탄소 복합재료의 부피 밀도와 표면과 내부의 부피 밀도의 차이를 특성치(characteristic value)로 한 실험계획법의 분산분석(analysis of variance)에 의하면 반응온도, 반응가스농도, 가스유량 등의 제고공정변수가 치밀화에 기여도가 높으며, 반응압력의 기여도와 제조공정변수들의 교호작용(interaction)에 의한 기여도는 낮은 것으로 나타났다. 반응온도가 $1100^{\circ}C$, 반응가스농도가 100% $C_3H_8$, 가스유량이 100 SCCM, 반응압력이 5torr인 조건에서 탄소/탄소 복합재료는 가장 높은 부피 밀도값을 나타내었으나 시편의 표면과 내부의 부피 밀도 차이값은 컸다.

Keywords

References

  1. Carbon v.25 no.2 The Future of Carbon-Carbon Composites Erich Fitzer
  2. Ceramic Bulletin v.67 no.2 Carbon-Carbon, An Overview John D. Buckley
  3. J. Phys. D;Appl. Phys. v.14 Structure and Strength of Carbon/Carbon Composites E. Fitzer;W. Huttner
  4. Ceram. Eng. Sci. Proc. v.9 no.7.8 Carbon/Carbon Composite Materials for Aircraft Brakes S. Swasthi;J. L. Wood
  5. Carbon v.29 no.4.5 Infiltration and Coating of the Porous Carbonaceous Bodies by Chemical Vapour Deposition S. T. Dimitrijevic
  6. Carbon v.29 no.3 Microstructure of Worn Pitch/Resin/CVI C-C Composite N. Murdie;C. P.Ju;J. Don;F. A. Fortunato
  7. Carbon v.12 Effect of Gas Phase Conditions on Resultant Matrix Pyrocarbons in Carbon/Carbon Composites M. L. Lieberman;H. O. Pierson
  8. Carbon v.23 no.6 Carbon/Carbon Composites Prepared by Chemical Vapor Deposition S. Marinkovic;S. Dimmitrijevic
  9. Chemistry and Physics of Carbon v.9 Deposition of Pyrolitic Carbon W. V. Kotlensky
  10. Carbon-Carbon Composites(1st ed.) G. Savage
  11. Quality Engineering Using Robust Design M. S. Phadke