Hydronalium

The Hydronalium alloys originated in Germany in the 1930s[1][2] and are best known, at least by that name, in Eastern Europe.

There are many alloys within this family, one standard reference listing over twenty.

[3] The alloy family is noted for its resistance to seawater corrosion.

The reliable strength of some grades is sufficient for aerospace use and so they are used for wetted components of seaplane aircraft, such as floats[2] and propellers, where marine corrosion resistance is also needed.

This, combined with their resistance to corrosion by salty sweat, has led to an application for violin strings as an alternative to silver.