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寂寞倾城(金币+5, 翻译EPI+1): 2011-03-03 15:11:17
It is interesting to consider the phase diagram that results if we exclude the Ta5N6 phase （e.g., if it is prevented from forming due to particular experimental conditions）. The result is shown in Fig. 4（d）. In this case, in addition to the Ta2N and Ta3N5 phases, which are now favorable over a larger region, the Ta4N5 structure appears in a relatively wide range of （ μN,μTa）phase space and, in addition, a structure containing N vacancies in a rocksalt lattice is seen （rs-Ta4N3）. It can be noticed that when sweeping from right to left in the phase diagram and going from high μN, low μTa to more low μN, high μTa conditions, the Ta to N ratio increases;namely, it changes from 0.6 （Ta3N5） to 0.8 （Ta4N5）to 1.33 （rs-Ta4N3） to 2.0 （Ta2N）; that is, the phases change from so-called “higher nitrides” to “lower nitrides.” This is similar to the trend found in Ref. 2 when heating the Ta3N5 phase under UHV as described in the Introduction, which causes desorption and loss of N atoms as N2, resulting in progressively more Ta-rich materials.
如果我们排除Ta5N6阶段（例如，如果由于特定的实验条件未能形成），考虑得到的相图将很有趣。结果如图4（d）所示。在这种情况下，除了目前已在更大区域有利的Ta2N和Ta3N5阶段，Ta4N5结构出现在一个比较宽的范围（μN，μTa）相空间，此外，可以看到一个包含了N空位是岩盐格结构（rs - Ta4N3）。可以注意到，当由右至左清扫相图，由高μN、低μTa，到更低μN、高μTa条件， Ta /N比增加，从0.6（Ta3N5）至0.8 （Ta4N5）至1.33（rs - Ta4N3）至2.0（Ta2N）改变，也就是说，相变是从所谓的“高氮化物”到“低氮化物”，变化趋势与在参考文献2发现的类似，如引言中所述，特高压下加热的Ta3N5相，这将导致脱附和氮原子以N2形式损耗，造成富Ta材料的逐步形成。 |
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