화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.165, No.14, A3389-A3396, 2018
Thermodynamic Analysis of AB(2) Hydrides: ZrCr1-xTixNiMo0.3 Alloys
A thermodynamic analysis was performed on the role of titanium substitution in ZrCr1-xTixNiMo0.3 (Ti; x = 0.3, 0.5, 0.7) AB(2) type alloys. The hysteresis in hydride/deshydruration processes was calculated from electrochemical isotherms as a dimensionless parameter related to yield strengths and hydrogen partial molar volumes. Zr(0.7)Ti(0.3)Cra(7)Mo(0.3)Ni samples exhibited large hysteresis, i.e. 1.6, but the lowest hydrogen molar volume (2.19 cm(3) mol(-1)) and the greater yield strength (10.0 x 10(6) N cm(-2)). Thus, the amount of titanium has to be carefully dosed to avoid large fractures and low hydrogen dosages. The multiphase formation was explained by Pm-3m and Im-3m space groups, the first one describing TiNi phase and the second one CrMo phase segregation. A brief evaluation of the thermodynamic works and non-compensated heats was also conducted. On one hand, the largest maximum and real work were obtained from Zr(0.7)Ti(0.3)Cra(7)Mo(0.3)Ni, between 700 and 800 J g(-1), although TiNi dissipates the lowest irreversible heat, -1 J, for attaining only half of the ideal and real works, between ca. 370 and 400 J g(-1). In summary, the presence of low amounts of titanium as those in Zr(0.7)Ti(0.3)Cra(7)Mo(0.3)Ni alloys balance well the electrochemical hydruration process with the mechanical and thermodynamic stability. (C) 2018 The Electrochemical Society.