Zr-Ni系合金の水素化物生成熱

概要

論文の詳細を見る
Hydrogen absorption alloys are widely used for tritium handling, such as its storage, supply and recovery. For such application, it is of paramount importance that the equilibrium dissociation pressure (Peq) of metal tritide be very low at room temperature and the temperature reaching Peq of 1 atm, (T1atm), not be too high. Thus, the thermodynamical properties related to the heat of formation of Zr-Ni deuteride instead of tritide were studied so as to find the best material. The composition of the Zr-Ni alloy used in this study was Zr9Ni11, which was characterized by X-ray diffractometry. The Zr9Ni11, activated in advance, was exposed to a given amount of deuterium at room temperature, and then the deuteride was heated stepwise to 300℃. Each temperature was kept constant for adequate time till Peq become constant. The data for both Peq and temperature were arranged by the van’t Hoff equation: lnPeq=(ΔHﾟ/RT)-(ΔSﾟ/R). Values of -ΔHﾟ=24～25kcal/mol[D2] and -ΔSﾟ=33～34kcal/mol[D2]・deg were obtained when atomic composition of deuteride was in the range from Zr9Ni11D1 to Zr9Ni11D3. From these values, Peq at 20℃ and T1atm were obtained as 10-6～10-7 Pa and ca. 450℃, respectively. The deuteride did not ignite even when exposed to the atmosphere at room temperature nor did it take on the form of a fine powder. These results thus show Zr9Ni11 to be a preferable material for storage-supply-recovery of tritium gas.
富山大学の論文