Microcantilever-assessed fracture toughness of industrially deposited TiZrN coatings at various nitrogen partial pressures

Abstract

TiZrN coatings were deposited using reactive magnetron sputtering under industrial conditions at three different nitrogen partial pressures: 0.008, 0.040, and 0.200 Pa. TiN and ZrN coatings were also prepared as reference materials. All ternary TiZrN coatings exhibited a face-centered cubic (FCC) structured solid solution. TiZrN coating deposited at a nitrogen partial pressure of 0.040 Pa exhibited the highest hardness of 31 ± 1 GPa, while TiN and ZrN approached 25 ± 3 GPa and 26 ± 1 GPa, respectively. The fracture toughness of the coatings was evaluated using the microcantilever bending method. KIC (critical stress intensity factor in mode I) for TiN reached 2.2 ± 0.4 MPa.m1/2 compared to 2.6 ± 0.3 MPa.m1/2 for ZrN. Incorporating Zr to TiN led to an enhanced fracture resistance by 17-27%, depending on the nitrogen partial pressure. The highest KIC recorded was 2.8 ± 0.3 MPa.m1/2, achieved at a partial pressure of 0.040 Pa.