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Effects of beadblasting on passivation layer

(-----) 2006

I use a beadblaster with a very fine grain of silica as a medium to thoroughly clean (not decontaminate) stainless surgical instruments. Does beadblasting effect the passivation layer in any way? If so is there any way or method to prevent any adverse effects. Thanks for any info you can offer.

Clifford Russell
surgical instrument repair - Lake Elsinore, California, USA
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First of two simultaneous responses -- 2006

The blasting will completely destroy the passive layer. However, if you use virgin media (or VERY clean media) the passive layer will reform. I would recommend a chemical passivation treatment after the blasting. Iron contamination from the blasting media would worry me too much.

Joseph Lockrem
- Indianapolis, Indiana, USA
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Second of two simultaneous responses -- 2006

Beadblasting at sufficient pressure disrupts and may contaminate the passivation layer. Although exposed stainless steel self-passsivates, this passivation layer is very thin. Hence, it is customary to (chemically) re-passivate after any blasting procedure.

Corrosion resistance decreases as surface roughness increases. Can you examine surfaces before and after blasting at high magnification? As an alternative to blasting, try a citric acid-based cleaner-passivation solution from Stellar Solutions [a finishing.com supporting advertiser].

Ken Vlach [dec]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
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