1.How to control surface morphology and roughness?
Selective removal and cleaning
Laser cleaning: High-energy pulsed laser instantly vaporizes surface oil, oxides and loose zinc slag, forming an ultra-clean surface of Ra 0.1~0.5μm, eliminating the potential risk of coating adhesion.
Retaining functional zinc layer: Laser parameters (wavelength, pulse width, energy density) are precisely controlled to remove only pollutants without damaging the underlying zinc coating.
Controllable micro-nanostructure construction
Laser roughening: Short-pulse laser (nanosecond/femtosecond level) scans the surface to form periodic micro-pits, increasing the roughness to the ideal anchoring range of Ra 2.0~6.0μm, and the mechanical locking effect increases the coating adhesion by 300%.
2.How does the composition and microstructure reconstruction perform?
Surface alloying
Laser melting: High-power laser remelts the surface zinc-iron diffusion layer to form a dense Zn-Fe intermetallic compound with a hardness of 250~400HV.
Increased wear resistance: The alloying layer's ability to resist sand erosion is increased by more than 5 times, making it suitable for building curtain walls in windy and sandy environments.
Oxide layer modification
In-situ generation of functional oxide film: Laser treatment in air can induce the formation of ZnO nanorods/porous ZnO layer, which has: self-cleaning property: photocatalytic degradation of organic matter; enhanced corrosion resistance: dense ZnO hinders Cl⁻ penetration.
3.What are the functional expansion features?
Super hydrophobic microstructure
Femtosecond laser engraving + low surface energy modification, constructing micron-level papillae + nano-level villi, contact angle >150°, rolling angle <5° (imitating the lotus leaf effect), so that galvanized steel has: Self-draining and anti-icing: reducing ice load in cold areas; Anti-pollution: building facades do not need to be cleaned.
4.What are the advantages of engineering applications?
Core advantages
Environmental protection: no abrasive dust, no chemical waste liquid, in line with green building standards;
Controllable precision: programmable graphics to process complex components;
Efficiency improvement: laser cleaning speed reaches 50m²/h;
Zero deformation of substrate: heat affected zone depth <20μm.
5.What are the limitations?
Cost: High-power laser equipment has high initial investment;
Lack of standards: There is no special national standard for laser treatment of galvanized steel;
Zinc evaporation control: Precise parameters are required to avoid excessive vaporization (zinc loss rate > 5% will reduce corrosion resistance).