In situ synchrotron X-ray diffraction with laser-heated diamond anvil cells study of Pt up to 95 GPa and 3150 K

Abstract

Platinum (Pt) has been widely studied for pressure calibration in high pressure–temperature ranges. We have for the first time performed in situ synchrotron X-ray diffraction (XRD) with laser-heated diamond anvil cells to study the P–V–T equation of state (EOS) for Pt up to 95 GPa and 3150 K. MgO was used for pressure calibration. A detailed analysis of the room-temperature compression curve was fitted with the third-order Birch–Murnaghan (BM) EOS, which yields ambient volume V₀ = 60.3 ų, isothermal bulk modulus K₀ = 308 GPa, and its pressure derivative K^′₀ = 4.1. A least-squares fit of the P–V–T data to a high-temperature (BM) EOS yielded K^′₀ = 5.5 ± 2, K₀ = 274 ± 36 GPa, αK_T(V₀, T) = 0.003 ± 0.0003 GPa K⁻¹ and (∂K_T/∂T)_V = 0.03 ± 0.01 GPa K⁻¹ with V₀ = 60.3 ų. Within a reasonable range, it is found that the EOS of this study is consistent with the known EOS of Pt. The present technique and results cover the P–T range between the resistive heating and the shock compression experimental data in the literature.