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Time requirements between plate and post-bake?

Q. Why is the time between plating and post-bake important? If a part receives a 4 hour post-bake instead of the 8 hr or 23 hr that may be required, what can be done? Why is the bake time sensitive?

Doug Davis
Project/Design Engineer - Tucson, Arizona, USA
2004

A. Because hydrogen is initially trapped between the plating layer and the parent metal. Over time, it diffuses into the metal, primarily along grain boundaries. The longer it is there, the deeper it goes into the metal. Baking is effective at removing the outer most hydrogen on/in the metal. It is less effective at removing deeper hydrogen. Thus, get it into the oven faster and limit your problems. The longer bake times will remove more of the deep hydrogen than a short bake time. Also note that the plating thickness has a great deal to do with the removal of the hydrogen as it must have a way to get out. Remember, that there is more hydrogen on/in the surface from the pickle or etch step than there is from the plating step in almost all situations. Please note that everything is relative. At what point does it become a serious problem.

James Watts
- Navarre, Florida
2004

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2006
Q. ASTM B633, Section 6, Paragraph 6.6 states: "Œ..shall be baked at a minimum of 190 °C for 3 hours or more within 4 hours after electroplating to provide hydrogen embrittlement relief."

Does this mean that there is only a one hour time window to get the plated part up to temperature in a bake oven?

Warren H. Anderson
- Elkhart, IN, USA