One of the most well discussed, and detrimental, embrittlement is hydrogen embrittlement in metals. There are multiple ways that hydrogen atoms can diffuse into metals, including from environment or during processing (eg. electroplating). The exact mechanism that causes hydrogen embrittlement is still not determined, but many theories are proposed and are still undergoing verification. Hydrogen atoms are likely to diffuse to grain boundaries of metals, which becomes a barrier for dislocation motion and builds up stress near the atoms. When the metal is stressed, the stress is concentrated near the grain boundaries due to hydrogen atoms, allowing a crack to nucleate and propagate along the grain boundaries to relieve the built-up stress.
There are many ways to prevent or reduce the impact of hydrogen embrittlement in metals. One of the more conventional ways is to place coatings around the metal, which will act as diffusion barriers that prevents hydrogen from being introduced from the environment into the material. Another way is to add traps or absorbers in the alloy which takes into the hydrogen atom and forms another compound.