7 documents found, page 1 of 1
Effect of substrate bias voltage on structural and tribological properties of W...
Ataie, S.A.; Soltanieh, M.; Naghizadeh, R.; Cavaleiro, A.; Evaristo, M.; Fernandes, F.; Ferreira, F.Protective multi-component thin films at the surface of cutting tools have been significantly developed to reduce wear and friction. The present work investigates the effect of substrate bias voltage on the structural-tribological relations of W-Ti-C-N thin films produced by HiPIMS and DCMS co-sputtering. Chemical analysis of the coatings is obtained and composite phase structure is revealed. Morphology of the ...
Ag (y) :TiN (x) thin films for dry biopotential electrodes: the effect of compo...
Pedrosa, P.; Machado, D.; Borges, Joel Nuno Pinto; Rodrigues, M. S.; Alves, E.; Barradas, N. P.; Martin, N.; Evaristo, M.; Cavaleiro, A.; Fonseca, C.In the present work, Agy:TiNx thin films, obtained by reactive DC magnetron sputtering, with decreasing [N]/[Ti] atomic ratios (from 1 to 0.1) and a fixed amount of Ag pellets placed in the erosion zone of a pure Ti target, were studied envisaging their application as biopotential electrodes. The strongly under-stoichiometric samples, [N]/[Ti] = 0.1 and 10 at.% Ag; [N]/[Ti] = 0.2 and 8 at.% Ag, were found to be...
Ag:TiN nanocomposite thin films for bioelectrodes : the effect of annealing tre...
Pedrosa, Paulo Eduardo Teixeira Baptista; Machado, Diogo; Evaristo, M.; Cavaleiro, Albano; Fonseca, Carlos; Vaz, F.Magnetron sputtered Ag:TiN thin films, with Ag contents ranging from 0 to ~50 at.%, were subjected to a set of annealing treatments at four different temperatures (from 200 to 500 ºC), aiming at studying the effect of Ag addition on their morphological and structural features, as well as on their electrical and mechanical properties. The increase of the annealing temperature revealed that significant morphologi...
Prediction of optimized composition for enhanced mechanical and electrochemical...
Velasco, Sebastian Calderon; Oliveira, J. C.; Evaristo, M.; Cavaleiro, A.; Carvalho, S.The necessity of improving the performance of existing biocompatible materials promotes the investigation of new approaches to solve biocompatibility problems caused by low chemical stability and poor mechanical performance of implanted materials. Envisioning those problems and considering the current reported complications of implanted stainless steel 316L devices, this work aimed to produce new Zr-C-N-Ag coat...
High temperature properties of the Cr-Nb-Al-N coatings with increasing Al contents
Li, W. Z.; Polcar, T.; Evaristo, M.; Cavaleiro, A.Cr-Nb-Al-N coatings with Al content from 0 to 12 at.% were deposited by d.c. reactive magnetron sputtering. The coatings were annealed in protective atmosphere at 800 and 900 °C for 1 h and exposed to air at 800, 900 and 1200 °C for different times. The chemical composition, structure, microstructure, hardness and adhesive/cohesive strength of the coatings, in as-deposited and annealed conditions, were investig...
Influence of Al content on the mechanical properties and thermal stability in p...
Li, W. Z.; Liu, H. W.; Evaristo, M.; Polcar, T.; Cavaleiro, A.Tools have been used under very high temperature in recent decades. Therefore, coatings on tools are required to be thermally stable and excellent in oxidation-resistance. The introduction of Al into nitride coatings was considered as an effective way to improve the coating oxidation-resistance and thermal stability. Quaternary Zr–Cr–Al–N coatings were deposited with increasing Al contents by d.c. reactive magn...
Carbon-based coatings doped by copper: Tribological and mechanical behavior in ...
Balestra, R. M.; Castro, A. M. G.; Evaristo, M.; Escudeiro, A.; Mutafov, Petr; Polcar, T.; Cavaleiro, A.We deposited C-based films doped with Cu and tested their sliding properties in olive oil as environment-friendly lubricant, which can be used in many mechanical systems, particularly in agriculture engineering. The coatings were deposited in a four unbalanced magnetron sputtering device combining C and C/Cu targets; argon (hydrogen-free films) and Ar/CH4 (hydrogenated films) atmospheres were used. Cu content o...