The authoritative public forum
  for Metal Finishing since 1989
-----

Baking of magnesium to out-gas contaminants?

2004

Dear Finishing,

Is baking of magnesium recommended prior to beginning the plating process? We've been having a blistering problem and I was wondering if we could out-gas some contaminants from the Mg surface by applying a 300-360F bake for 30 - 60 mins. We don't, however, have a vacuum oven and may actually make the metal more porous by doing so (?). Any knowledge of this?

Randall Fowler - Fowler Industrial Plating, LLC
Cleveland, Tennessee, USA

---

2004

High pressure die castings are frequently pre-baked prior to application of coatings due to the entrapped gas porosity inherent in this process. Baking of Mg die castings is usually done around 80 C. This may lead to a problem with leveling if the surface is pitted, which may be remedied by depositing an acid copper layer first (> 8 micrometers). You can find more information in ASM Handbook Volume 5 Surface Engineering.

Toby Padfield
Automotive module supplier - Michigan