Tribological behaviour of C-alloyed transition metal dichalcogenides (TMD) coatings in different environments

• Autor(a) principal: Evaristo, Manuel
• Data de Publicação: 2008
• Outros Autores: Polcar, Tomas, Cavaleiro, Albano
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/7652; https://doi.org/10.1007/s10999-007-9034-2

Abstract W-S-C films were deposited by non-reactive sputtering from a carbon target incrusted with WS2 pellets in the eroded zone. This process allows depositing coatings with a wide range of compositions, with a precise control of their carbon content. Before the deposition, a Ti interlayer was interposed between the film and the substrate to improve the final adhesion. The carbon content in W-S-C system was varied from 29 at.% to 70 at.%, which led to an hardness enhancement from 4 GPa up to 10 GPa where the maximum hardness was reached in films with a carbon content between 40 at.% and 50 at.%. The tribological behaviour of the coatings was evaluated by pin-on-disk testing, in environments with different humidity levels. Generally, the tribological performance of W-S-C coatings in environments with moderate to high humidity is better for coatings with high carbon content. Friction coefficients, as 0.05 or lower could be reached at low humidity ranges (<7%) to all compositions. However, for higher humidity values, friction coefficient increased up to 0.30 in the W-S-C film with low carbon content whereas it was kept approximately constant for the others compositions.