Fretting Wear Performance of CrN Coating after Laser Shock Peening

• Low-energy laser shock peening (LE-LSP) significantly enhances the surface hardness of CrN coatings, with a maximum increase of 2.35 times at 150 mJ laser energy. • LE-LSP treatment disrupts the columnar crystal structure of CrN coatings, fragmenting grains into finer sizes, which contributes to improved mechanical properties. • The fretting wear resistance of CrN coatings is optimized at 150 mJ laser energy, achieving a 76.32% reduction in wear volume compared to untreated coatings. • The study introduces a novel post-treatment methodology for PVD coatings, providing theoretical support for PVD/LSP composite strengthening techniques.