Study on Compressive Behavior of -Fe2SiO4 under Hydrostatic Pressure

The compressive behavior of -Fe2SiO4 at high pressure up to 23 GPa and room temperature has been measured by using synchrotron radiation and in situ high pressure X-ray diffraction techniques with DAC. The p-V relationship of -Fe2SiO4 at 0～23 GPa indicated that the isothermal compression process can be divided into two steps: if K0'=4, the bulk modulus K0 =1892 GPa at 0～18 GPa, and K0=21.32 GPa at 18～23 GPa. We didn't find any imformation of the phase transformation of -Fe2SiO4 in the whole experimental process. Based on the experimental data, it seems to us that the sample was in quite good hydrostatic pressure up to 18 GPa, but was in non-hydrostatic pressure due to solidification of the liquid medium when the pressure beyond 18 GPa. Finally, the phenomenon that the sample with incorrect loading method has higher K0 in those hydrostatic pressure experiments is discussed.