Cr-N hard coatings were deposited by ion beam assisted magnetron sputtering technique(IBAMS). Indentation test was used to measure the coatings fracture toughness. The repeated impact test was applied to evaluate the impact fatigue resistance. The relations of the impact fatigue resistance with coatings microstructure and mechanical properties were analyzed. The results show that both the hardness and fracture toughness of Cr-N coatings are improved by adjusting ion assisted bombardment energy. The improvements of hardness and fracture toughness are related to the decreasing grain size and coatings densification. The failure mode of Cr-N coatings under impact load is cohesion fatigue failure. The impact fatigue resistance is improved with coatings hardness and fracture toughness increasing.

Cr-N coatings; IBAMS; fracture toughness; repeated impact

Taiyuan University of Technology; Xi'an Jiaotong University