Work Function Measurement of Lanthanum - Boron Compounds
Work Function Measurement of Lanthanum - Boron Compounds
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DOI：
10.1109/tps.1978.4317109
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发表时间：
1978-06
影响因子：
1.5
通讯作者：
D. Jacobson;E. Storms
中科院分区：
文献类型：
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作者：
D. Jacobson;E. Storms
在 LaB4.24 和 LaB29.2 之间以及 1400 和 2100 K 之间对 La-B 体系进行了研究，以确定相关系、组分的化学活性、汽化速率和蒸气组成。发现 LaB9 附近的蓝色相存在于紫色 LaB6 和元素硼之间。扩散比汽化慢得多，因此表面和内部之间可能存在较大的成分差异，尽管如此，自由汽化材料会产生稳态损失率。 LaB4 + LaB6 在 1700 K 下的通量为 6 × 10-10 g/cm2-sec，LaB6 + LaB9 为 7 × 10-11 g/cm2-sec。存在降低硼从 LaB6 蒸发速率的活化能。自由蒸发的材料将具有介于 LaB6.04 和 LaB6.07 之间的稳态表面成分，具体取决于温度、纯度和内部成分。在 1700 K 和 2100 K 之间，LaB6 的形成自由能为 (0.071T-351) kJ/摩尔。
The La-B system was studied between LaB4.24 and LaB29.2, and between 1400 and 2100 K to determine the phase relationship, the chemical activity of the components, the vaporization rate and the vapor composition. A blue colored phase near LaB9 was found to exist between purple colored LaB6 and elemental boron. Diffusion is so much slower than vaporization that large composition differences can exist between the surface and the interior which, nevertheless, produce a steady state loss rate from freely vaporizing material. The flux at 1700 K is 6 × 10-10 g/cm2-sec for LaB4 + LaB6 and 7 × 10-11 g/cm2-sec for LaB6 + LaB9. There is an activation energy which lowers the vaporization rate of boron from LaB6. Freely vaporizing material will have a steady state surface composition between LaB6.04 and LaB6.07, depending on temperaure, purity and interior composition. The free energy of formation of LaB6 is (0.071T-351) kJ/mole between 1700 K and 2100 K.