Composite CrN/HVOF coatings for superior high-temperature wear resistance

Artikel i vetenskaplig tidskrift, 2026

CrN coatings possess excellent hardness but suffer from rapid degradation under high-temperature sliding, largely due to limited toughness and substrate softening. In this work, we introduce a composite coating architecture, consisting of a CrN top layer supported by NiCrBSi or Stellite12 high-velocity oxy-fuel (HVOF) interlayers, designed to improve high-temperature load-bearing capacity and wear performance. Reciprocating sliding tests up to 600 °C demonstrate that the composite systems exhibit substantially reduced wear rates compared with monolithic CrN, enabled primarily by the mechanical support of the HVOF interlayers, which effectively suppress substrate plasticity and crack formation. Cross-sectional TEM of worn regions reveals that CrN accommodates high-temperature deformation through a sequence of dislocation activities, partial dislocation slip generating stacking faults and nanotwins, and stress-assisted amorphization at grain boundaries. While these mechanisms provide additional strain accommodation, they are not sufficient to prevent severe damage in monolithic CrN. In contrast, the composite coating maintains structural integrity and shows a transition to predominantly mild oxidative wear, highlighting the critical role of the interlayer in stabilizing the CrN film under thermomechanical loading. This study demonstrates that engineering a load-bearing composite architecture provides an effective pathway to achieve high-temperature wear resistance in nitride ceramic coatings, while offering new insight into the high-temperature deformation behaviors of CrN.