Abstract
Hydrogen absorption during electroplating might result in hydrogen embrittlement (HE) of the substrate metal. Heat treatment ("baking") is commonly employed "in order to render the normally mobile hydrogen immobile". The objective of this work was to develop a sensitive analytical procedure using dynamic secondary ion mass spectrometry (SIMS) that would allow identification of improper baking during quality control. In all non-baked samples of AISI 4340 steel coated with cadmium, an increase in the hydrogen signal was found at the Cd/steel interface. In baked samples, either a peak was not observed at the interface, or it was found insignificant based on determination of the ratios between the hydrogen signals within the coating, interface and substrate. The results were reproduced after 16 months storage in a desiccator. The main effect of baking was found to be effusion of hydrogen from the interface and the substrate steel into the atmosphere. HE-related delayed failures may thus be explained in terms of a time-independent reservoir of hydrogen at the coating/substrate interface, rather than in terms of irreversible damage that occurred within the substrate during electroplating. These findings contradict some of the statements in textbooks and international standards.
Original language | English |
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Journal | NACE - International Corrosion Conference Series |
State | Published - 2011 |
Event | Corrosion 2011 - Houston, TX, United States Duration: 13 Mar 2011 → 17 Mar 2011 |
Keywords
- Baking
- Cadmium coating
- Delayed failure
- Electroplating
- High-strength steels
- Hydrogen embrittlement
- Hydrogen trapping
- Quality control
- Secondary ion mass spectrometry (SIMS)
All Science Journal Classification (ASJC) codes
- General Chemistry
- General Chemical Engineering
- General Materials Science