Tribological behaviour of reactive and co-sputtered W-S-C coatings

 

M. Evaristo ⁽¹⁾, A. Nossa ⁽²⁾, A. Cavaleiro ⁽¹⁾

 

⁽¹⁾ ICEMS Grupo de Materiais e Engenharia de Superfícies – Faculdade de Ciências e Tecnologia da Universidade de Coimbra – Rua Luís Reis Santos, 3030-788 Coimbra, Portugal

albano.cavaleiro@dem.uc.pt

⁽²⁾ Escola Superior de Tecnologia e Gestão, Instituto Politécnico da Guarda, Guarda, Portugal

 

 

ABSTRACT: W-C-S films were deposited either by a reactive process in an Ar+CH₄ atmosphere or by co-sputtering WS₂ and C targets. The films were characterized concerning their chemical composition and mechanical properties. The results showed that the films, in both systems, have similar properties. Co-sputtered films are amorphous, whereas in the reactive process a gradual l oss of cristallinity is observed with the increase of C content in the films. The hardness and the adhesion are similar for both systems. The increase of C alloying to the films led to the improvement of both their hardness and adhesion.

The tribological performance of the coatings was tested by ball-on-disk. The films deposited by co-sputtering present better results than the reactive deposited ones. With the increase of C content in these coatings an increase of the wear resistance is observed, reaching in the best case a wear coefficient of 3.1×10^-16 m³/N×m. In the films deposited by reactive process, low wear coefficients can also be reached but no regular trend with increasing C contents can be observed.

Keywords: Tungsten disulfide; WS₂; Friction coefficient; Wear coefficient; Self-lubricant

 

 

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