Hydrogen in Metals

Abstract

This monograph examines the mechanisms of hydrogen absorption and retention in massive solid metals, phenomena historically encapsulated by Thomas Graham’s term “occlusion.” It explores the underlying causes and direct consequences of hydrogen occlusion, synthesizing empirical data from diverse studies. Key focus areas include the effects of occlusion on lattice parameters, X-ray spectral diffusion, electrical resistance, magnetic susceptibility, and other material properties. The literature on hydrogen-metal interactions is extensively reviewed, with emphasis on empirical findings rather than theoretical deductions. While theoretical works on hydrogen diffusion and solubility in metals are acknowledged in the bibliography, their discussion is limited to instances where assumptions align with or conflict with observed data. The analysis prioritizes experimental observations and their direct implications, maintaining a self-contained empirical framework. This approach complements traditional X-ray crystallography by addressing structural sensitivities at critical dimensional scales, offering insights into metallic properties shaped by occlusion. To maintain focus, topics such as adsorption, catalysis, and broader metallurgical applications—already covered in specialized literature—are omitted except where incidental references are necessary. Similarly, indirect consequences of occlusion (e.g., long-term material degradation) are briefly addressed or excluded, as detailed in Chapter I. The monograph includes an annotated bibliography of ~1,470 references , compiled to ensure near-completeness on primary occlusion research up to late 1946 . Additional references on closely related topics (e.g., lattice dynamics, metallic property studies) are included where relevant to the text or footnotes. Later references post-1946 are selectively noted in the bibliography but not discussed in the main text.