Abstract: A protective coating for a copper alloy substrate includes a layer of a transition metal, referred to as primer layer, and a corrosion protection layer formed by at least one portion of the primer layer. The primer layer includes the transition metal combined with an oxidized transition metal. A process for depositing the protective coating is by physical vapor deposition (PVD) technology. The substrate is positioned in a chamber, with a target made of a transition metal, the chamber being supplied with various gases. The substrate is dehumidified and descaled. A thin primer layer of transition metal is deposited on substrate and bombarded with a mixture of argon ions and oxygen ions. A corrosion protection layer is formed by oxidizing the transition metal of the primer layer.

Abstract: A helmet having an outer shell defining a convex outer surface and an opposite concave inner surface circumscribing an inner cavity to receive the wearer's head is provided. The helmet has an inner liner connected to the outer shell and located in the inner cavity, where the inner liner contacts the wearer's head when the helmet is worn. The inner liner includes a padding arrangement including a plurality of padding substructures disposed at selected locations in the inner cavity, where at least one of the plurality of paddings has a shear resistance along a shear direction lower than a compressive resistance along a compressive direction, where the compressive direction extends transversally to the shear direction. The helmet also has an attachment device for securing it on the wearer's head.