Hydrogen Embrittlement

What is Hydrogen Embrittlement?

Hydrogen embrittlement is a chemical process that causes certain metals to become brittle and highly susceptible to fracturing.  This occurs when metals are subjected to excess hydrogen absorption during the finishing process. Because hydrogen atoms are smaller in size than the other atoms that compose the metal they are able to migrate into the crystal lattice amplifying the tendency to fail under stress.  In the plating process they hydrogen is available from both the aqueous plating bath as well as the pickling solution. Due to this fact, even electroless plating process are not immune to embrittlement. 

 

The potential for embrittlement exist in a wide range of metals but, hardened steels (> 40 Rc) are particularly susceptible. Fortunately, hydrogen is readily liberated through baking. The requirement for baking is a time-at-temperature cycle that is generally specified on the part print or within a plating specification.  A typical cycle is to bake at 375ºF for 4 hours within 1 hour after plating. Technical Plating offers baking as a part of our service. 

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