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High-Pressure High-Temperature Synthesis of Si-C-N Phases

High-Pressure High-Temperature Synthesis of Si-C-N Phases. Miria Andrade 1 , Dmytro Dzivenko 1 , Gerhard Miehe 1 , Peter Kroll 2 , Stefan Lauterbach 1 , Hans-Joachim Kleebe 1 and Ralf Riedel 1. 1 Material- und Geowissenschaften, Technische Universität Darmstadt, Darmstadt, Germany.

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High-Pressure High-Temperature Synthesis of Si-C-N Phases

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  1. High-Pressure High-Temperature Synthesis of Si-C-N Phases Miria Andrade1, Dmytro Dzivenko1, Gerhard Miehe1, Peter Kroll2, Stefan Lauterbach1, Hans-Joachim Kleebe1and Ralf Riedel1 1 Material- und Geowissenschaften, Technische Universität Darmstadt, Darmstadt, Germany 2 Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, USA

  2. Contents • Introduction /Motivation • Previous theoretical work • HP/HT Synthesis of Si-C-N Phases • Summary

  3. N “C3N4“ γ-Si3N4 SiC2N4 Si2CN4 Si Cd Introduction/ Motivation B ~ 425-496 GPa Harder than diamond? B = 290 GPa HV = 30-43 GPa B = 442 GPa HV ~ 96 GPa

  4. SiC2N4 and Si2CN4 Phases -SiMe3Cl SiCl4 + Me3Si-NCN-SiMe3 [Si(NCN)2]n(NCNSiMe3)x 350°C Vacuum SiC2N4 400-600°C 900°C SiC2N4 β-SiC2N4 (HT) Si2CN4 -C2N2 -N2 150-160°C α-SiC2N4 (LT) R. Riedel et al., Angew. Chem. Int. Ed. Engl., 1997, 36, 603-606

  5. SiC2N4 and Si2CN4 Phases b-SiC2N4≡ Si(N=C=N)2 Cubic (Pn3m)  = 1.51 g/cm3 Si2CN4 ≡ Si2N2(N=C=N) Orthorhombic (Aba2)  = 2.32 g/cm3

  6. P=10-20 GPa P=20-30 GPa Some Theoretical Work on HP/HT Behavior of Si-C-N Phases HP-Si2N2(NCN)Pc SiN4-tetr. SiN6-oct. B0 = 133 GPa Si2N2(NCN) Aba2 SiN4-tetr. B0 = 110 GPa α-Si(NCN)2 P4322 SiN4-tetr. B0 = 19 GPa HP-Si(NCN)2P4322 SiN6-oct. B0 = 84 GPa P. Kroll, J. Gracia, R. Riedel, Mater. Res. Soc. Symp. Proc. 1040 (2008)

  7. Theoretical Work on Spinel-type Si-C-N Phases W. Y. Ching, S. D. Mo, I. Tanaka, M. Yoshiya, Phys. Rev. B 63 (2001) J. E. Lowther, M. Amkreutz, T. Frauenheim, E. Kroke, and R. Riedel, Phys. Rev. B 68 (2003) H. Wang, Y. Chen, Y. Kaneta, S. Iwata, Eur. Phys. J. B 59 (2007) X. Zhang, Z. Chen, H. Du, C. Yang, M. Ma, J. He, Y. Tian, R. Liu, J. of Appl. Phys. 103 (2008) H.J. Du, L.C. Guo, D.C. Li, D.L . Yu, J.L He, Chin. Phys. Lett. 26 (2009)

  8. HP/HT Behaviour of Si-C-N Phases HP/HT Synthesis Shock Wave Multi-Anvil Press LH-DAC 30 GPa 10 – 22 GPa 27 – 33 GPa

  9. Multi-Anvil Experiments P = 22 GPa T = 1500°C t = 5-30 min Freiberg High Pressure Research Centre (2009)

  10. Multi-Anvil Experiments Freiberg High Pressure Research Centre (2009) SiC2N4 Multi-anvil assembly (10M) 22 GPa 1500°C/5 min MAC201 1500°C/30 min MAC202 Quenching

  11. Characterization of HP/HT Samples • Identification of phases: • Synchrotron Radiation X-Ray Diffraction • Determination of the composition: • EDX-TEM • EELS-TEM • Rietveld structure refinement

  12. Structural Characterization MAC202 22 GPa – 1500°C/ 30 min D  Diamond MAC201 22 GPa – 1500°C/ 5 min G  Graphite  Spinel Synchrotron radiation (λ = 0.3654 Å)

  13. EDX-TEM Spinel-type phase Si, C, N and O have been detected semi-quantitatively by EDX. The composition with respect to C/N/O content should be confirmed by EELS measurements

  14. EELS-TEM Spinel-type phase Saturation prevented the observation of the C edge.

  15. EELS-TEM Spinel-type phase O : N = 0.2  0.03

  16. Si-C-N-(O) System Rietveld structure refinement MAC202 γ-Si-C-N-(O) + diamond Si2.40C0.40N3.33O0.66 [Si1.800.20]oct[Si0.60C0.40]tetN0.33O0.66

  17. γ-Si-C-N-(O) SixCyNzOw Thick samples (crystal size of 0.3 - 0.5 mm) might have caused saturation. Attempts to break the crystals were not successful.

  18. Multi-Anvil Experiments • Lower pressures (10 - 15 GPa) • Moderate temperatures (800 – 1200°C) • t = 30 min Freiberg High Pressure Research Centre (2011)

  19. Multi-Anvil Experiments Freiberg High Pressure Research Centre (2011) SiC2N4 Si2CN4 Al2O3-NaSiO3-Cement Mo 10 - 15 GPa ZrO2 Thermocouple 800 – 1200°C In2O3- Bi2O3 Si-C-N HD-BN Quenching Graphite furnace ZrO2 ‏ Mo

  20. Multi-Anvil Experiments Freiberg High-Pressure Research Centre (2011) In order to prevent oxygen contamination, the encapsulation procedure has been improved

  21. SiC2N4 (PK106) P = 10 GPa T = 825°C Partial crystallization of a-Si3N4 lMo = 0.7093 Å

  22. SiC2N4 (PK107) P = 10 GPa T = 945°C Amorphous lMo = 0.7093 Å

  23. HP/HT Behaviour of Si-C-N Phases 10 GPa a-Si3N4 → Amorphous • Decomposition of the ternary system • Amorphization upon increasing T

  24. Si2CN4 (PK104) a-Si3N4 b-Si3N4 P = 10 GPa T = 895°C lMo = 0.7093 Å

  25. Si2CN4 (PK105) P = 10 GPa T = 1080°C Platinum The sample was requenched 3x Amorphous lMo = 0.7093 Å

  26. HP/HT Behaviour of Si-C-N Phases 10 GPa a-b-Si3N4 → Amorphous • Decomposition of the ternary system • Amorphization upon increasing T

  27. Si2CN4 (PK108) P = 15 GPa T = 1110°C Partial crystallization of a-Si3N4 lMo = 0.7093 Å

  28. Si2CN4 (PK109) P = 15 GPa T = 1280°C b-Si3N4 + a-Si3N4 + SiO2 (stishovite) + Graphite + Pt lMo = 0.7093 Å

  29. b-Si3N4 → g-Si3N4 PK108 P = 15 GPa T = 1110°C PK109 P = 15 GPa T = 1280°C No transition to g-Si3N4! Togo, A. and Kroll, P., First-principles lattice dynamics calculations of the phase boundary between b-Si3N4 and g-Si3N4 at elevated temperatures and pressures. Journal of Computational Chemistry, 2008.

  30. HP/HT Behaviour of Si-C-N Phases 15 GPa a-Si3N4 → b-Si3N4 • Decomposition of the ternary system • Crystallization of Si3N4 upon increasing T

  31. HP/HT Behaviour of Si-C-N Phases • Higher pressures • Higher temperatures

  32. LH-DAC Experiments Starting Materials: SiC2N4 (SiC1.8N3.56O0.1) Si2CN4 (Si2C1.28N3.60O0.07) P = 27 - 33 GPa 1500 K < T < 2100 K Loading: MPI Mainz Heating: Laser Heating Facility Frankfurt In order to prevent hydrolysis of the starting materials, the DACs were loaded in the glovebox.

  33. SiC2N4 (Sample 1) P = 33 GPa T > 2000 K Synchrotron radiation λ= 0.3660 Å Spinel + KBr (pressure medium)

  34. Si2CN4 (Sample 2) P = 29 GPa T > 1500 K Synchrotron radiation λ= 0.3660 Å Spinel + KBr (pressure medium)

  35. Si2CN4 (Sample 2) P = 29 GPa T > 1500 K Synchrotron radiation λ= 0.3660 Å Spinel +Stishovite + KBr (pressure medium)

  36. Shock-wave Experiments Flyer-plate Apparatus FP_C2-01  SiC2N4 FP_S2-01  Si2CN4 Pressure: 30 GPa Temperature: extremely hot

  37. Shock-wave Experiments λ = 0.3654 Å C  Copper 3 diffraction peaks could not be indexed to any known phase!

  38. Shock-wave Experiments (TEM) • Amorphous + Graphite Phase • The phase detected by XRD could not be found by TEM! • Beam-sensitive phase? 10 nm

  39. Summary • Ambient pressure phase of Si(NCN)2 transforms into a spinel-type γ-SixCyNz(Ow)-phase at 22 GPa pressure and 1800 K together with formation of carbon phase as a side product. Rietveld refinement suggests Si2.40C0.40N3.33O0.66 as the composition. • Under lower pressures (10 – 15 GPa) and moderate temperatures, Si(NCN)2 and Si2N2(NCN) phases decompose into Si3N4, whereas amorphization takes place upon increasing temperature. • Oxygen and water-free atmosphere is a critical factor to be considered for the successful HP/HT synthesis of Si-C-N phases.

  40. Acknowledgements • T. Schlothauer, Dr. M. Schwarz, Prof. E. Kroke (TU Bergakademie Freiberg) • Dr. T. Palasyuk, Dr. M. Eremets (MPI-Mainz) • Dr. L. Bayarjargal (Uni-Frankfurt) • ESRF (ID31 and ID09A) • DFG/SPP1236 for financial support

  41. Thank you for • your attention!

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