Metal finishing Q&As since 1989

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Selective surface etching of WC parts

I need high-strength polished pistons for a material testing press, but they must have porous facings. One approach would be to find a microporous tungsten carbide source, but another would be to leach the binder from an existing carbide part. Most finishing processes seek to limit binder loss in WC, whereas I need to rapidly but controllably strip enough binder to create a fine porous layer at the piston surface without fundamentally changing the bulk crushing strength of the part. Any recipes for a possible stripping protocol would be very much appreciated for this application.

Dr Stephen Elphick
University of Edinburgh - Edinburgh, Scotland
2003

If the binder in the WC is Co you may want to try a dilute Sodium Hydroxide or Ammonium Hydroxide. The cobalt will be removed leaving a skeleton of WC.

Robert Sachs
- Morrisburg, Ontario
2003