Chapter 7 - Hydrogen Permeation and Hydrogen-Induced Cracking

Abstract

Hydrogen evolution and permeation occur during electroplating, corrosion, and cathodic protection. Hydrogen accumulates in areas of high stress and may reach a critical concentration, potentially causing fractures and catastrophic damage. This chapter describes hydrogen permeation and hydrogen-induced damage in metals and alloys. It also discusses hydrogen evolution kinetics, theoretical diffusion solutions, and basic hydrogen permeation models. Models are used as a diagnostic tool to determine the effectiveness of various metals and alloys as hydrogen permeation inhibitors. It then explains experimental atomic hydrogen permeation transient determination and hydrogen absorption rate constants and diffusivity evaluation into metals using case studies. Hydrogen embrittlement, hydrogen-induced cracking, hydrogen blistering, and hydrogen stress cracking are also discussed to show the relationship to hydrogen permeation and hydrogen-induced cracking mechanisms. Finally, various techniques used to prevent and control hydrogen damage of metals and alloys are described.