Laser surface processing and aqueous corrosion resistance.

Over the past fifteen years, the development of new high-power laser sources and the reduction of production costs have encouraged the emergence of various material transformation processes to which lasers bring their flexibility and ease of use. Such is the case with diode and fiber lasers, which combine small size, competitive price and high power, making them compatible with most traditional laser applications (welding, cutting, direct manufacturing, micro-machining), including surface treatments. Laser surface processing of metallic materials can be carried out in a number of distinct interaction regimes, and with passage through different states of matter: solid, liquid, gas, plasma.

In what follows, we will review the surface functionalization possibilities offered by power lasers, focusing on improving resistance to aqueous corrosion, and presenting the physical principles of the various processes, the associated surface transformations and the final properties of parts in more or less aggressive environments. We will look more specifically at localized corrosion problems (intergranular corrosion, pitting corrosion, stress corrosion, exfoliative corrosion) for which lasers have most often been considered. Finally, we will distinguish the specific contribution of these processes according to the nature of the metal alloys treated, considering essentially three classes of passivatable materials: stainless steels, aluminum alloys and titanium alloys.