Thermodynamic Parameters and Equation of State of Low‐Density SiO2 Aerogel

This paper studies properties of low‐density SiO2 aerogel of initial density ρo = 0.08 g/cm3, 0.15 g/cm3, and 0.19 g/cm3 in shock compression up to ∼ 13 GPa pressures in plane‐ and semispherical‐geometry devices. Shock‐wave velocities up to ∼14 km/s, luminance temperatures up to ∼20000 K, light absorptivity α ∼ (1–4)103 cm−1 in a shock‐compressed aerogel, and sound speed are measured with the optical method in visible spectrum (λ = 406, 498, 550, and 600 nm). Thermodynamic parameters of liquid‐state aerogel are calculated by the equation of state using the modified van der Waals model for reactive mixtures.