Definition
A form of metal damage in which hydrogen atoms penetrate the structure of a high-strength steel part, causing the metal to lose ductility and become brittle. The part may then crack or fail suddenly under loads it would normally handle without difficulty. Hydrogen embrittlement is most commonly introduced during electroplating processes such as cadmium plating, and is prevented by baking the part at a specified temperature for a specified time after plating to drive the hydrogen back out.
Plain English
When hydrogen gets trapped inside a steel part during certain manufacturing or plating processes, the metal becomes brittle and can snap unexpectedly. Heating the part for a set time after plating drives the hydrogen out and restores its strength.
Context Anchor
Seen in aircraft maintenance when discussing metal parts that have been cleaned with acid, plated, exposed to corrosion, or otherwise treated in ways that may let hydrogen enter the metal.
Derivation
Embrittlement comes from the word brittle, meaning easily broken. Hydrogen embrittlement literally means being made brittle by hydrogen — a useful name because it tells you both the cause and the result.
Why Pilots Care
It can lead to unexpected failure of critical components such as bolts, landing gear, or engine parts, creating serious safety risks.
Grounding Statement
A steel part can look normal on the outside but still be weakened inside if hydrogen has entered the metal.
Intuition Check
Hydrogen embrittlement is not just surface rust or ordinary corrosion. The main danger is hydrogen inside the metal making it crack more easily under stress.
Example Sentence 1
After cadmium plating the landing gear bolts, the technician baked them for the specified time to prevent hydrogen embrittlement.
Example Sentence 2
Preventing hydrogen embrittlement involves careful control of chemical treatments on aircraft structural components.