I'm glad to see work happening on this area.

HF has been unavoidable in metallography. Particularly with aluminum alloys where practically all standard etchants call for it and it's often used in combination with concentrated HCl and HNO3. Picric is another acid that is hard to avoid in metallography.

It would be great to see more safer etchants developed and added to industry test standards so that their use can extend outside of academia where labs are bound by a2La accreditation rules.

Keep up the great work!

Yaritza Brinker

260.827.5402

From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Andy Glode
Sent: Tuesday, June 8, 2021 9:55 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: [DCHAS-L] alternative etchant for metal samples

** External Email **

Hi all,

I am late in sharing a significant innovation one of our students, Nick Ferreri, made last year that will be of interest to this group. I presented safety training to a group students who were planning to use HF as an etchant. Nick took it upon himself to research alternatives to HF and developed a method that eliminated HF use from his preparation method for titanium samples. The alternative method uses ethylene glycol, ethanol, sodium chloride, and a low voltage charge. Please note that concentrated acids and high voltage are not used in this etch method, completely avoiding the major hazards historically associated with titanium metal preparation for electron microscopy. And, the resulting etch is better than if the sample had been etched with HF. Please share this with colleagues who may use HF to etch titanium and titanium alloys.

The published article describing the method is here:

https://www.sciencedirect.com/science/article/pii/S1044580320303363

Thanks!

Andy

Andy Glode, MS, CIH

Interim Director

Office of Environmental Health and Safety

University of New Hampshire

O: 603-862-5038; C: 603-534-9872

https://www.unh.edu/research/environmental-health-and-safety

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