The Thermodynamics of the Scandium-Hydrogen System1,2
The Thermodynamics of the Scandium-Hydrogen System1,2
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DOI：
10.1021/j100894a044
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发表时间：
1965-10
期刊：
影响因子：
--
通讯作者：
M. L. Lieberman;P. G. Wahlbeck
中科院分区：
文献类型：
--
作者：
M. L. Lieberman;P. G. Wahlbeck
近年来，人们对金属-氢体系表现出极大的兴趣，因为需要稳定的金属氢化物，即具有低平衡氢压的氢化物。在所研究的过渡金属-氢系统和稀土金属-氢系统中，Y-H系统123表现出最大的稳定性。目前只有有限的数据可用于钪-氢系统。McGuire和Kempter4报告了他们认为是两个冷凝相区的有效温度-压力数据，这两个冷凝相区位于钪中的氢固溶体和一个明显缺氢的二氢化物相之间。他们报告了室温下与ScH2相对应的最大氢组成。027.Beck5报道了钪-氢系统的温度-压力-组成数据。WARF和HardCastle6报告说，在400和40大气压的条件下，无法制备三氢化钪相。而YTTrium3和几种稀土金属7的三氢化物相是在不那么严格的条件下制备的。这项工作的目的是测定热力学数据和建立钪-氢体系的相图。实验部分装置。对西弗茨装置进行了改进，使平衡氢压在10-4毫米之间。和一个自动取款机。可以测量的数据用于获得压力-温度-组成数据。这种装置在其他地方也有描述。1-3种材料。本研究中使用的Sc2C>；3由爱荷华州立大学艾姆斯实验室通过还原从美国钪公司获得。艾姆斯实验室对金属进行的分析显示出以下杂质：O，1805ppm；N，80ppm；H，15ppm；Y，0.03%；Er，<；0.01%；Tm，<；0.01%；Yb，<；0.004；Lu，<；0.01%；Si，80ppm；Ca，320ppm；Fe，180ppm；和Ta，1000ppm。转角是通过至少漂洗三次来清洁的
Recently, great interest has been shown in the metal-hydrogen systemsbecause there is a need for stable metal hydrides, ie, hydrides which exhibit low equi-librium hydrogen pressures. Ofthe transition and rare earth metal-hydrogen systems investigated, it appears that the yttrium-hydrogen system1 23 exhibits the great-est stability. Only limited data have been available for the scandium-hydrogen system. McGuire and Kempter4 reported measurements which they believed to be valid temperature-pressure data for the two-condensed-phase region between a solid solution of hydrogen in scandium and an apparently hydrogen-deficient dihydride phase. They reported a maximum hydrogen composition at room temperature corresponding to ScH2. 027. Beck5 reported temperature-pressure-composition data for the scandium-hydrogen system. Warf and Hardcastle6 reported inability to prepare a scandium trihydride phase under conditions of 400 and 40 atm. whereas trihydride phases of yttrium3 and of several of the rare earth metals7 have been prepared under less stringent conditions. The purposes of this work were the determination of thermodynamic data and the establishment of the phase diagram for the scandium-hydrogen system. Experimental SectionApparatus. A Sieverts apparatus modified so that equilibrium hydrogen pressures between 10-4 mm. and 1 atm. could be measured was used to obtain pressure-temperature-composition data. The apparatus has been described elsewhere. 1-3 Materials. The scandium used in this research was prepared from Sc2C> 3 obtained from the American Scandium Corp. by reduction at the Ames Laboratory of Iowa State University. An analysis of the metal performed by the Ames Laboratory showed the follow-ing impurities: O, 1805 ppm; N, 80 ppm; H, 15 ppm; Y, 0.03%; Er,< 0.01%; Tm,< 0.01%; Yb,< 0.004%; Lu,< 0.01%; Si, 80 ppm; Ca, 320 ppm; Fe, 180 ppm; and Ta, 1000 ppm The metal was work-hardened to the extent that it could be trimmed on a cleaned lathe to produce fine turnings. The turnings were cleaned by rinsing at least three