Thermal Oxidation of Cold Sprayed Titanium-Based Coating Deposited on Co-Cr Alloy

Çetiner D., Paksoy A. H., Tazegül O., Baydoğan M., GÜLERYÜZ H., Çimenoğlu H., ...More

JOURNAL OF THERMAL SPRAY TECHNOLOGY, vol.27, no.8, pp.1414-1427, 2018 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 27 Issue: 8
  • Publication Date: 2018
  • Doi Number: 10.1007/s11666-018-0772-5
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1414-1427
  • Keywords: coating, Co-Cr alloy, cold spray, thermal oxidation, titanium, wear, METAL-ION RELEASE, SURFACE MODIFICATION, CORROSION, TI, DIFFUSION, WEAR, IMPLANTS, OXYGEN
  • Istanbul Technical University Affiliated: Yes


This study focuses on the surface modification of a medical grade Co-Cr alloy via combining cold spray and thermal oxidation processes. After deposition of a Ti96-Al4 (wt.%) coating, samples were oxidized at 600 degrees C for 60h in air. Oxidation transformed the coating into a dual-layered structure comprising an outer oxide layer (mainly rutile) with a diffusion layer (mainly oxygen enriched titanium and Ti-Al intermetallics) beneath it. Formation of new phases made the diffusion layer brittle and prone to fracture during pull out tests. Scratch and Rockwell-C tests confirmed good adhesion between the oxide and underlying diffusion layers, having average hardness as 1297 HV and 387 HV, respectively. The dual-layer coating exhibited excellent wear performance in a 0.9wt.% NaCl solution against sliding action of alumina ball as compared to Co-Cr substrate, especially at contact pressures<1200MPa, while the maximum in vivo contact pressure is<15MPa for load-bearing orthopedic implants. Furthermore, the release of the aluminum from the dual-layer coating into 0.9wt.% NaCl solution is lower than the permissible limit stated by the International Agency for Research on Cancer.