a-C(:H) and a-C(:H)_Zr coatings deposited on biomedical Ti-based substrates: Tribological properties

Polcar

et al. 2013

Wear

High-pressure torsion was employed to refine the microstructure of grade 2 Ti under an imposed pressure of 3.0 GPa at room temperature. The microhardness of grade 2 Ti increased from 1.82 GPa for the coarse grain state to 3.05 GPa after high-pressure torsion processing, where this value is very close to the hardness of the Ti-6Al-4V alloy.Subsequently, several diamond-like carbon (DLC) coatings with thicknesses of ~1.4 Pm were deposited on as-received Ti, high-pressure torsion processed Ti and Ti-6Al-4V samples via physical vapour deposition. Both indentation and scratch tests showed a much improved adhesion of DLC-7Zr, DLC:H-7Zr and DLC-9Zr coatings with high-pressure torsion processed Ti as the substrate by comparison with the same coatings on coarse-grained Ti. The results suggest that commercial pure Ti processed by high-pressure torsion and coated with a diamond-like carbon coating provides a potential candidate material for bio-implant applications.

Section: Mechanical Properties Of Ti Substratesmentioning

confidence: 91%

“…Recently, zirconium was used as a dopant metal to provide low-toxicity, good tribological behaviour and high corrosion resistance [32][33][34].…”

Section: Introductionmentioning

confidence: 99%

Indentation and scratch testing of DLC-Zr coatings on ultrafine-grained titanium processed by high-pressure torsion

Wang

Polcar

et al. 2013

Wear

“…The depositions were carried out in an Ar atmosphere with substrates rotating at 17 cm from For more details see Ref. [14].…”

Section: Methodsmentioning

confidence: 99%

“…The incorporation of metal atoms such as Ti [11], W [12], Cr [13], Zr [14], Cu [2] or Ag [15, 16,17], to carbon films could reduce residual stress and thus the risk of premature coatings adhesion failure. These metals might form small nanocrystallites of pure metal or metal carbide nanograins dispersed through the carbon structure [10].…”

Section: Introductionmentioning

confidence: 99%

Influence of Ag content on mechanical and tribological behavior of DLC coatings

Manninen

Ribeiro

Surface and Coatings Technology

et al. 2013

Self Cite

101

Ag-DLC coatings with Ag contents ranging from 1.3 at.% to 13.1 at.% were deposited by DC magnetron sputtering. The coatings were characterized with respect to their structure (by means of XRD and Raman Spectroscopy), mechanical and tribological properties (by scratch test, nanoindentation, residual stress measurements and pin-on-disk test). The incorporation of 13.1 at.% Ag resulted in the formation of Ag grains with 2-3 nm which promoted the increase of graphite like bonds organized in rings. Regarding the mechanical properties, no variations were found for films with Ag contents lower than 13 at.%; a reduction of both hardness and compressive residual stress were then observed for higher values. Pin-on-disk tests were performed at two different contact pressures (690 MPa and 1180 MPa) in dry sliding conditions against a zirconia counterpart. For the lower contact pressure the variations in the wear rate are well correlated with the coatings structure and mechanical properties, while for higher contact pressure the presence of Ag is relevant, Ag-DLC coatings showing higher wear rate than DLC one. SEM analysis revealed the formation of Ag aggregates on the wear track and adhesion of silver to the counterpart.

“…The deposition time was set to deposit coatings approximately 1.6 µm thick. Further deposition details can be found elsewhere [20]. To facilitate reading, the coatings were denominated as a-C_Zr(X) and a-C:H_Zr(X) for non-hydrogenated and hydrogenated coatings, respectively, where X is the approximate Zr content.…”

Section: Coatings Depositionmentioning

confidence: 99%

Structural and mechanical properties of nanocrystalline Zr co-sputtered a-C(:H) amorphous films

Applied Surface Science

Figueiredo

Polcar

et al. 2015

Self Cite

Abstract:The aim of this study was to investigate the effect of Zr as alloying element to carbon films, particularly in respect to film structure and mechanical properties. The films were deposited by magnetron sputtering in reactive (Ar+CH 4 ) and non-reactive (Ar) atmosphere with different Zr contents (from 0 to 14 at.%) in order to achieve a nanocomposite based films. With an increase of Zr content a broad peak was observed in X-ray diffraction spectra suggesting the presence of nanocrystalline (nc) ZrC phase for the coatings with Zr content higher than 4 at.%. The application of Scherrer formula yielded a grain sizes with a dimension of 1.0-2.2 nm. These results were supported by X-ray photoelectron spectroscopy showing typical charge transfer at Zr-C nanograins and carbon matrix interface. The nc-ZrC phase was also observed by transmission electron microscopy. The hardness of the coatings was approximately independent of Zr content. However, the Young modulus increased linearly. The residual stress of the coatings was strongly improved by the presence of nc-ZrC phase embedded in the a-C matrix. Finally, the incorporation of H into the matrix led to denser and harder films.