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fusion

ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC. future energy production. fusion . 1983 2015 2040.

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fusion

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  1. ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC future energy production fusion 1983 2015 2040 PREPARATION AND ANALYTICAL ELECTRON MICROSCOPY OF SiC CONTINUOUS-FIBER REINFORCED SiC-BASED MATRIX COMPOSITE Goran Drazic, Sasa Novak, Nina Daneu, and Katja Mejak Department for Nanostructured Materials Jozef Stefan Institute, Ljubljana, Slovenia JET ITER DEMO hydrogen → helium @ 10 M˙C

  2. ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC fusion tokamak Sakharov & Tamm 1950 toroidalnaya kamera magnitnaya plasma @ 100 M°C Fusion compared to other E sources: Almost limitless fuel supply (D in water, T from Li).  No greenhouse gas emissions. Suitable for the large-scale electricity production  Waste from fusion will not be a long-term burden  The transport of radioactive materials is not required  The system has inherent safety aspects. Very low risk of radioactive emissions to the environment The Joint European Torus (JET) (Culham, UK)

  3. ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC ITER (latin: the way) ITER fusion reactor www.iter.org Fusion Energy Research for the duration of FP6 is EUR 750 million

  4. ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC first reactor wall aims • Eurofer • Ti-alloys • SiC(f)/SiC Improve the existing SiCf/SiC composite Impermeability:coating & impregnation SiC(f)/SiC High thermal conductivity: reduced porosity, purity, grain boundary phases High mechanical strength: high density; appropriate microstructure; nano-sized particles Short-living descendants: suitable sintering additives (LPS) Easy (low-cost) preparation: wet-ceramic processes (dispersed suspensions..) • SiCf/SiC : •  Low activation after fast-neutron irradiation • Acceptable mechanical properties at high temperatures •  Insufficient thermal conductivity (high porosity after CVI) • Insufficient gas-impermeability (high porosity or cracking) • Current technology (CVI) requires very long processing time (weeks) and is extremely expensive 500 um 2 mm 200 um CVI SiCf/SiC

  5. 500 nm ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC material tailoring SiC material preparation • SiC is a highly covalent bonded compound  difficult densification • Sintering: • - Solid-state sintering: B, C • - Liquid-phase sintering (LPS): MeO • SiC-Al2O3-Y2O3 Al2O3 + SiC  Al2O(g) + SiC(g) + CO(g) • SiC-AlN-Y2O3 2AlN  2Al(l) + N2(g) • X-based liquid phase (ceramic-glass composite) Low-temperature densifed SiC for the specific application SiC – AlN – Y2O3 Coating techniques: adapted dip-coating (DIP) sec. phase GB Infiltration techniques: vacuum slip infiltration (VSI) electrophoretic deposition (EPD) 100 nm Suspensions: wetting, packing density, rheology Grain Boundaries, secondary phase

  6. high medium Mg low hands on years ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC chemical composition fast neutron activation fission: half-life of Pu: 24,000 years 5 half-lives are needed for 99% decay calculated gamma dose for various ITER related materials (The European Activation System: EASY-2001 Code, R. A. Forrest, UKEA-Fus-449, 2001,courtesy by Dr. George Vekinis, Institute of Materials Science, NCSR Demokritos, Athens, Greece)

  7. T AlN Y2O3 ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC SEM SiC – AlN – Y2O3 Y2O3 amount plays an important role SEM of the SiCf/SiC interface

  8. ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC TEM SiC – AlN – Y2O3 Si C Al Y Si C C c-p A Y2O3 rich secondary phase is crystalline intergranular phase is amorphous SEM of the SiCf/SiC interface

  9. ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC STEM - HAADF SiC – AlN – Y2O3 AlN SiC: Zav. = 10 AlN: Zav. = 10 10 nm SiC STEM - DF 10 nm Y2O3 rich secondary phase is uniformly distributed STEM - HAADF

  10. ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC liquid phase sintering SiC – SiO2 ceramic - glass (controllable atmosphere) glass redistribution solid phase rearrangement viscous flow of glass phase simulation of SAED patterns TEM comparison of experimental and simulated SAED patterns

  11. Experimental SiC cubic Experimental cristobalite SiC hexagonal Experimental (4H) ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC phase composition SiC – SiO2 ceramic - glass (controllable atmosphere) simulation of SAED patterns TEM comparison of experimental and simulated SAED patterns

  12. 10 um ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC adapted dip coating SiC – SiO2 ceramic - glass(controllable atmosphere) adapted dip coating SiC – SiO2 SiC fiber SiCf/SiCCVI SEM 100 mm 200 nm TEM of SiCf/SiC / matrix interface TEM

  13. 1 nm ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC ceramic – glass composite SiC (nano) – (P2O5) – Al2O3 reactive glassy phase 50 nm HRTEM phase diagrams – low T liquid phase

  14. SiC/Si-(P)-Al-O 10 nm reaction layer 50 nm SiC fiber ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC vacuum slip infiltration SiC (nano) – (P2O5) – Al2O3 high amount of glassy phase 10 nm SEM TEM of SiCf/SiC matrix interface

  15. ASM 2004 Columbus, OH USA October 18 – 21, 2004 Goran Drazic – AEM of SiCf/SiC ITER starts ~ 2015 DEMO reactor ~ 2040 ? acknowledgement The work has been financed by projects: Novel processing of SiC/SiC by slip infiltration of SiC fiber pre-forms with SiC under vacuum (SINF)EURATOM, FP6, FU06-CT-2003-00323, 2004 Gas impermeable coatings for SiCf/SiC (SICOAT)EURATOM, FP6, FU06-CT-2003-00322, 2004 conclusions Vacuum-slip infiltration (VSI) is a promising alternative to chemical vapor infiltration (CVI) Limitations are given by matrix material: SiC-AlN-Y2O3 can be sintered @ 2000°C to a high density SiC-SiO2 system: volume fraction of glassy phase can be controlled with sintering atmosphere SiC-P205 can be sintered < 1500°C to a pore-free material To Do list: Sintering: - additives for SiC (no Y, Al; nano-powders) - no shrinkage Analysis of the SiCf/SiC matrix composite: - high-temperature mechanical properties - thermal conductivity - gas permeability

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