Enhanced mechanical properties of CrN coatings by plasma immersion ion implantation and deposition

Crystal defects can enhance the properties of materials without changing the composition but introduction of high-density defects in coatings is challenging. Herein, plasma immersion ion implantation and deposition (PIII&D) is employed to produce high-density crystal defects in CrN coatings to improve the mechanical properties. PIII&D is demonstrated to introduce high-density point defects and stacking faults into the CrN coatings, especially at a bias exceeding 10 kV. The dislocation density significantly increased from 5.2 × 10¹⁴/m² to 1.3 × 10¹⁷/m². In addition, the covered area of defects increased from 30% to 75% with the ion implantation. As a result, the hardness increases significantly from 24.2 GPa to 35.6 GPa, while the fracture toughness is not compromised.