AVS 51st International Symposium
    Advanced Surface Engineering Tuesday Sessions
       Session SE-TuP

Paper SE-TuP7
Microstructural Evolution on the Oxidation of Arc Ion-plated TiN/(Ti,Al)N Superlattice Coatings

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: M.H. Shiao, National Science Council, Taiwan
Authors: M.H. Shiao, National Science Council, Taiwan
C.C. Wang, National Chung Hsing University, Taiwan
F.S. Shieu, National Chung Hsing University, Taiwan
Correspondent: Click to Email
TiN/(Ti,Al)N superlattice coatings with a TiN interlayer were prepared by a dual-cathode arc ion plating system on AISI 304 stainless steel. Two targets of Ti and Ti@sub 50@Al@sub 50@ were used for the vertically opposited cathodes. Oxidation of the nitride-coated steel was carried out at the temperature of 800°C in air for 60 min. The microstructure and chemistry of the as-deposited and oxidized specimens was characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Auger electron spectroscopy (AES). XRD result shows that nitride coatings have strong (111) preferred orientation, and TiO@sub 2@ phase appeared in the oxidized specimen. Cross-sectional TEM reveals a TiN/(Ti,Al)N superlattice structure with a period of 7.7 nm examined by the selected area diffraction (SAD). In the oxidized specimen, there are dense amorphous Al@sub 2@O@sub 3@ layer and underlying porous TiO2 layer on the surface of the coating. Auger depth profiling of the oxidized specimens reveals that the Al element concentration near the surface layer is much higher than that in the nitride coating, and further confirmed the cross-sectional TEM results.