Hydrogen embrittlement is a phenomenon that can occur during the electroplating process. It arises from the absorption of atomic hydrogen by certain metals, which can lead to a loss of ductility and increased susceptibility to cracking and fracture.
During electroplating, metal ions from a plating solution are reduced and deposited onto a substrate, typically through the application of an electric current. In some cases, hydrogen gas (H2) can be generated at the cathode (the object being plated) during the electrochemical reaction. This hydrogen gas can then diffuse into the metal substrate.
The presence of atomic hydrogen within the metal lattice can cause several mechanisms that contribute to embrittlement:
Hydrogen-enhanced localized plasticity (HELP): Hydrogen atoms can accumulate at regions of high stress concentration, such as notches or cracks in the metal. The presence of hydrogen reduces the ability of the material to deform plastically, making it more prone to brittle fracture.
Hydrogen-induced cracking (HIC): In certain metal alloys, hydrogen can cause the formation of internal cracks or fissures. These cracks can propagate and lead to catastrophic failure, even under relatively low applied stress.
Hydrogen-induced delayed cracking (HEDE): This form of embrittlement occurs when a hydrogen-charged component fails several hours or days after the hydrogen absorption. It is commonly observed in high-strength steels and can be influenced by factors such as residual stresses, microstructural features, and environmental conditions.
To mitigate hydrogen embrittlement during electroplating, several approaches can be taken, such as using specialized plating techniques, employing hydrogen embrittlement-resistant alloys, applying post-plating baking or stress-relief treatments to remove absorbed hydrogen, or implementing proper design considerations to minimize stress concentrations.
It's important to note that the specific conditions and materials involved in the electroplating process can impact the severity of hydrogen embrittlement. Therefore, it's crucial to consult relevant literature, industry standards, and experts in the field for detailed guidance on preventing and managing hydrogen embrittlement in specific electroplating applications.