Feasibility Study on the Generation of Nanoporous Metal Structures by Means of Selective Alloy Depletion in Halogen-Rich Atmospheres

Jörg Weise; Birgit Uhrlaub; Dirk Lehmhus; Joachim Baumeister; Kerstin Hantzsche; Karsten Thiel

doi:10.3390/ma17020498

Feasibility Study on the Generation of Nanoporous Metal Structures by Means of Selective Alloy Depletion in Halogen-Rich Atmospheres

Materials (Basel). 2024 Jan 20;17(2):498. doi: 10.3390/ma17020498.

Authors

Jörg Weise¹, Birgit Uhrlaub¹, Dirk Lehmhus¹, Joachim Baumeister¹, Kerstin Hantzsche², Karsten Thiel¹

Affiliations

¹ Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Strasse 12, D-28359 Bremen, Germany.
² Leibniz Institute for Materials Engineering-IWT, Badgasteiner Str. 3, D-28359 Bremen, Germany.

Abstract

A new approach to produce nanoporous metals has been investigated, which is based on the dealloying of bi- or multi-component alloys. Depletion and pore formation of the alloy substrate are obtained by the transport of certain alloy components at high temperatures via volatile halogen compounds. These halogen compounds are transferred to materials acting as sinks based on their higher affinity to the respective components, and chemically bound there. Transfer via volatile halogen compounds is known from the pack cementation coating process and from high-temperature corrosion in certain industrial atmospheres. The approach was tested on different precursor alloys: Ti-43.5Al-4Nb-1Mo-0.1B (TNM-B1), TiNb42, and AlCu. Both dealloying effects and micro-scale pore formation were observed. The detailed size of the porous structures is in the range of 50 nm for both TNM-B1 and TiNB42 and 500 nm for AlCu.

Keywords: alloy depletion; dealloying; halogen; nanoporous metals; porous materials.

Grants and funding

This research received no external funding.