Etchant for Thin Film Media
Etchant for Thin Film Media
(OP)
Hi,
I'm searching for the correct type of etchant for thin film media. I need to etch away the Chromium and Cobalt layers which underneatch layer is Nikel/Phosphorus and the base material is Al. I also briefly know that Hydrochloric acid and Nitric acid may work; but I need to retain the Silicon Oxide Particle/Material on the media surface. Thanks in advance.
I'm searching for the correct type of etchant for thin film media. I need to etch away the Chromium and Cobalt layers which underneatch layer is Nikel/Phosphorus and the base material is Al. I also briefly know that Hydrochloric acid and Nitric acid may work; but I need to retain the Silicon Oxide Particle/Material on the media surface. Thanks in advance.





RE: Etchant for Thin Film Media
have you made any progress on an etchant for thin film media.
I am also interested in this. My application is to chemically destroy the platters of hard drives as a means of secure disposal for redundant drives.
Regards,
Paul.
RE: Etchant for Thin Film Media
For stripping Cr from (electroless) nickel, a 12.5 vol. % Hydrochloric acid solution (125 ml of 37 wt% HCl per Liter) is recommended. I do not know of a suitable solution for stripping Co from Ni, since these 2 metals are chemically similar.
To strip Cr, Ni, etc. from Al or SiO2, use concentrated nitric acid (67-70 wt.%).
To also destroy the Al or SiO2 substrate, include some HF with HCl & HNO3.
For information on stripping metallic coatings from various base metals, see
http://www.metalfinishing.com/WZ/MetalFinishing/guidebooks/MetalGB_SurfaceTreatments/000016/show/
RE: Etchant for Thin Film Media
I worked on 37wt% HCl both no dilution and 50% dilution (during Feb till now). So far, this is a better ones. I have also tried on concentrated nitric acid (67-70 wt.%), the layer Cr,Co, Ni are being stripped off and left only the Al.
Kenvlach mentioned that to destroy the Al or SiO2 substrate, include some HF with HCl & HNO3. May I know the concentration and ratio ? Thanks.
Lastly, anybody knows the suitable solution for stripping Cobalt from Ni where the underneatch layer is Nikel/Phosphorus ? Thanks in advance.
Regards,
SFChong.