Laser Assisted High Pressure Phase Transformation in SiC

1. Laser Assisted High Pressure Phase Transformation in SiC Principle Investigator: Dr. John Patten Research Assistants: Saurabh R. Virkar and Thomas Kremenski Argonne National Laboratory –Advance Photon Source Synchrotron Facility in Chicago Dr. Vitali Prakapenka examines a DAC sample.

2. Experimentation Process At the heart of the experimentation was the diamond anvil cell (DAC). In order to simulate the stresses of machining, our specimen had to be subjected to pressures up to 100 GPa with temperature exceeding 2000˚ K by laser Diamond Anvil Cell

3. The Diamond Anvil Cell Laser Beam for heating the sample Laser Beam for heating the sample

4. Objectives: • To duplicate the pressure and temperature encountered during SiC machining • To study the phase transformation at high pressure and temperature • To better understand micro-laser machining process (µ-LAM)

5. SETUP:

6. CONTROL PANEL

7. Material used: Powder for 4H SiC in 150 µm tip diamond Powder of 4H SiC in 300 µm tip diamond Powder of 6H SiC in 150 µm tip diamond IPG Laser 100 W

8. Results: Phase transition in 4H SiC at 66 GPa and 1550 K temperature Phase transition in 6H SiC at 88GPa and 1550 K temperature

9. Results on CCD image for 4H SiC: Before Phase transition in 4H SiC After Phase transition in 4H SiC

10. X-ray diffraction pattern in 4H SiC X-ray diffraction pattern before (black line) and after phase transformation (pink line) in 4H SiC

11. Results on CCD image of 6H-SiC Before phase transformation in 6H SiC After phase transformation in 6H SiC

12. X-ray Diffraction pattern for 6H SiC X-ray diffraction pattern before (black line) and after phase transformation (pink line) in 6H SiC

13. FUTURE WORK Data Analysis TEM of the sample µ- Raman to analyze the absorption at high pressure Assembly of Diamond Anvil Cell for next test

14. THANK YOU