Effect of Mn substitution on plateau pressure regulation of the Ti0.92Zr0.1Cr1.6−xMnxFe0.4 alloys for primary hydrogen compressor

Abstract

The Ti0.92Zr0.1Cr1.6−xMnxFe0.4 (x = 0.15, 0.3, 0.45, 0.6 at%) alloys were synthesized by vacuum electric arc furnace. The effect of Mn substitution on plateau pressure regulation of these alloys was investigated for the primary hydrogen compressor. With increasing Mn content, the hydrogen absorption/desorption plateau pressures of the Ti0.92Zr0.1Cr1.6−xMnxFe0.4 (x = 0.15, 0.3,0.45,0.6 at%) alloys increased, the plateau slope factor decreased, meanwhile, both enthalpy and entropy change values decreased. The Ti0.92Zr0.1Cr1.0Mn0.6Fe0.4 alloy had the best comprehensive performance. Based on the pressure composition isotherms measurement, the plateau pressure and hydrogen storage capacity were obtained at 298–363 K. The hydrogen absorption/desorption curves of the Ti0.92Zr0.1Cr1.0Mn0.6Fe0.4 alloy at 353 and 363 K were firstly tested by experiment method. At 298 K, the hydrogen absorption plateau pressure and maximum capacity were 7.82 MPa and 1.79 wt%. At 363 K, the hydrogen desorption plateau pressure and maximum capacity were 27.21 MPa and 1.54 wt%. Hydrogen pressure from 8 MPa to 25 MPa was successfully obtained at 298–363 K, satisfying operating temperature and pressure requirements for the primary hydrogen compression materials.