Mechanical properties of Al<inf>2</inf>O<inf>3</inf>-functionalized nanoporous gold foams under irradiation

Nanoporous gold (np-Au) has unique properties due to its high surface-to-volume ratio; in particular, it displays different degrees of radiation sensitivity, from radiation tolerance to significant radiation-induced hardening. However, its thermal instability and propensity to coarsening limit practical applications. It is known that oxide functionalization of np-Au surface improves thermal stability and increases both hardness and elastic modulus of the metallic foam. Nevertheless, the changes in the material properties under irradiation have not been investigated yet. In this work, we address the questions of radiation sensitivity of atomic layer deposition (ALD)-coated np-Au, and how its mechanical properties change after irradiation. ALD Al2O3-coated gold nanofoams were synthetized and irradiated with Ne++ ions and their mechanical behavior was evaluated by nanoindentation. It is concluded that the as-prepared functionalized np-Au hardens and stiffens after ion irradiation depending on the dose, without losing toughness and wear resistance. Graphic abstract: [Figure not available: see fulltext.].