Self-mated tribological systems based on multilayer micro/nanocrystalline CVD d...

• Author(s): Salgueiredo, E. ; Abreu, C. S. ; Amaral, M. ; Oliveira, F. J. ; Gomes, J. R. ; Silva, R. F.
• Date: 2013
• Persistent ID: http://hdl.handle.net/10400.22/3478
• Origin: Repositório Científico do Instituto Politécnico do Porto
• Subject(s): Diamond multilayers; Nanocrystallinediamond; Hot filament CVD; Friction; Wear
• Document Type: Article
• Language: English

Description

The tribological response of multilayer micro/nanocrystalline diamond coatings grown by the hot filament CVD technique is investigated. These multigrade systems were tailored to comprise a starting microcrystalline diamond (MCD) layer with high adhesion to a silicon nitride (Si3N4) ceramic substrate, and a top nanocrystalline diamond (NCD) layer with reduced surface roughness. Tribological tests were carried out with a reciprocating sliding configuration without lubrication. Such composite coatings exhibit a superior critical load before delamination (130–200 N), when compared to the mono- (60–100 N) and bilayer coatings (110 N), considering ∼10 µm thick films. Regarding the friction behaviour, a short-lived initial high friction coefficient was followed by low friction regimes (friction coefficients between 0.02 and 0.09) as a result of the polished surfaces tailored by the tribological solicitation. Very mild to mild wear regimes (wear coefficient values between 4.1×10−8 and 7.7×10−7 mm3 N−1 m−1) governed the wear performance of the self-mated multilayer coatings when subjected to high-load short-term tests (60–200 N; 2 h; 86 m) and medium-load endurance tests (60 N; 16 h; 691 m).