TOF-SIMS depth profiling and element mapping on oxidized AlCrVN hard coatings

V-alloyed AlCrN hard coatings were deposited on silicon wafers (Si (100)) by reactive arc evaporation in a commercial coating system at 500 °C for 10 min, resulting in a coating thickness of ∼500 nm. The chemical composition of the stoichiometric coatings is constant at approximately Al_0.70Cr_0.05V_0.25N regardless of the applied bias voltage during deposition. Coatings synthesized at a low bias of −40 V show a dual-phase structure (hexagonal close-packed and face-centered cubic (fcc)), whereas coatings deposited at a high bias of −150 V have a metastable single-phase structure (face-centered cubic). All samples were oxidized for 15 min under 20 mbar O₂ atmosphere and at four different temperatures (550, 600, 650, and 700 °C). The oxidized coatings were subject to depth profiling and element mapping by a time of flight secondary ion mass spectrometry instrument, equipped with a Bi-cluster analysis gun and Cs⁺-sputter gun. The evaluation of the in-depth distribution of several elements and species points out distinctive differences in the oxidation behavior of the two different coatings, whereas element mapping shows the formation of islands made of oxidized vanadium and aluminum species as the top-most layer of the single-phase (fcc) coating at temperatures above 650 °C.