Kiyotaka Kato

Wetting Behavior for Ni on (Ti0.95Mo0.05)(C0.5N0.5), (Ti0.9Nb0.1)(C0.5N0.5) and (Ti0.85Nb0.1Mo0.05)(C0.5N0.5) Substrates

Wetting tests for Ni on (Ti0.95Mo0.05)(C0.5N0.5), (Ti0.9Nb0.1)(C0.5N0.5) and (Ti0.85Nb0.1Mo0.05)(C0.5N0.5) ceramics were carried out at 1823K and compared with those for the previous data. The larger the Mo content was, the smaller the contact angles were. The contact angle for (Ti0.85Nb0.1Mo0.05)(C0.5N0.5) was smaller than for (Ti0.95Mo0.05)(C0.5N0.5). No new phase was observed on cross sections of the wet tested samples and microstructures could be divided into three regions: a Ni-rich region, reactive region, and substrate region. The depth of reactive region/height of Ni-rich region ratios for titanium carbonitrides containing Nb were larger than those for them containing Mo, and (Ti0.85Nb0.1Mo0.05)(C0.5N0.5) had the largest ratio in all the samples. [doi:10.2320/matertrans.M2012351]

Effect of Titanium/Oxygen Compositional Gradient on Adhesion of Titanium-Oxygen System Film deposited onto Titanium-based Alloy by Reactive DC Sputtering

Abstract Coating of titanium-based alloy such as Ti-6A1-4V with Ti-O compositionally gradient films was carried out by reactive DC sputtering, in order to improve not only the biocompatibility of the alloy1) but also the adhesion between the deposited film and the alloy substrate with preserving the high hardness of Ti-O films2). The effects of Ti/O compositional gradient on adhesion of the film to the alloy substrate were investigated by comparing the adhesion of Ti-O compositionally gradient films to the alloy substrates with that of Ti-O compositionally constant films to the alloy substrates. The compositional gradient was realized by varying continuously the oxygen content in Ar-O2 sputter gas mixture during the sputter-deposition. According to AES in-depth profiles, the oxygen(O) concentration in the deposited film decreased gradually in-depth direction from the surface toward the substrate, confirming that a film with Ti/O compositional gradient, i.e., a Ti-O compositionally gradient film had formed on the alloy substrate, and thereby expecting that the stress concentrated at the interface between the deposited film and the alloy substrate could be relaxed. On the basis of indentation-fracture tests, it was found the compositionally gradient films were more adhesive to the alloy substrates than the compositionally constant films, concluding that the Ti/O compositional gradient improved the adhesion of the deposited Ti-O films to the alloy substrates

Enhanced Industrial Applicability of Aluminum Alloy by Coating Technique With Titanium/Carbon Compositionally Gradient Film Using Magnetron Co-Sputtering

Coating of Aluminium alloy substrates with Ti/C compositionally gradient films was examined by magnetron sputtering, in order to improve not only the abrasion resistance of the alloy but also the adhesion between the deposited film and the alloy substrate with preserving the high hardness of such ceramic coatings. The Ti/C compositionally gradient films were deposited by co-sputtering of 2 sputter cathodes which had a pure titanium target and a titanium carbide target respectively, and their compositionally gradient was realized by varying continuously the electric power supplied to each sputter cathode. Under visual observation, the obtained Ti/C compositionally gradient films appeared to be uniform and adhesive. According to AES in-depth profiles, the carbon (C) concentration in the film gradually decreased in depth direction from trhe surface toward the substrate, confirming that a Ti/C compositionally gradient film had formed on the alloy substrate. On the basis of XRD, it was found that titanium carbide and α-titanium phases were formed in the gradient film. Furthermore the Vickers hardness of the film reached over Hv=2600. Therefore the abrasion resistance of the alloy and the adhesion of the hard coatings were expected to be improved by this method.© 2002 ASME