Lithium hydride (LiH) is a unique, ionic compound with applications in a variety of industries. Unfortunately, LiH is very reactive toward H2O even at ppm levels, forming oxide (Li2O) and hydroxide (LiOH) corrosion layers while outgassing H2. An effective means to eliminate unwanted outgassing is vacuum-heating to convert LiOH into Li2O, although subsequent re-exposure to moisture during transport/handling reconverts some Li2O back to LiOH. A corrosion growth model for previously vacuum-baked LiH is necessary for long-term prediction of the hydrolysis of LiH. In this work, a para-linear hydroxide corrosion growth model is proposed for the reaction of previously vacuum-baked LiH samples with moisture. This model, composed of two competing diffusion reaction fronts at the LiOH/Li2O and Li2O/LiH interfaces, is validated experimentally by subjecting a previously vacuum-baked polycrystalline LiH sample to 35 ppm of H2O at room temperature while monitoring the corrosion growth as a function of time with diffuse-reflectance infrared Fourier transform (DRIFT) spectroscopy. The para-linear growth model for the hydrolysis of previously vacuum-baked LiH proposed in this report can also serve as a template for the hydrolysis of other hygroscopic oxides grown on metal or metal hydride substrates.

中文翻译：

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LiH的水分腐蚀：通过DRIFT光谱进行动力学研究。

氢化锂（LiH）是一种独特的离子化合物，已在许多行业中得到应用。不幸的是，即使在ppm级，LiH对H2O的反应性也很强，在除掉H2的同时会形成氧化物（Li2O）和氢氧化物（LiOH）腐蚀层。消除有害气体的有效方法是真空加热，将LiOH转化为Li2O，尽管随后在运输/处理过程中再次暴露于湿气中，也会将部分Li2O转化回LiOH。长期真空烘焙的LiH的腐蚀增长模型对于长期预测LiH的水解是必要的。在这项工作中，提出了一种对线性氢氧化物腐蚀增长模型，用于先前真空烘焙的LiH样品与水分的反应。该模型由LiOH / Li2O和Li2O / LiH界面上的两个竞争扩散反应前沿组成，通过在室温下将预先真空烘焙的多晶LiH样品置于35 ppm H2O的同时，通过漫反射红外傅里叶变换（DRIFT）光谱监测腐蚀随时间的变化来进行实验验证。本报告中提出的用于先前真空烘焙的LiH水解的准线性生长模型也可以用作水解在金属或金属氢化物基材上生长的其他吸湿性氧化物的模板。