Indentation modulus extrapolation and thickness estimation of ta-C coatings from nanoindentation

Lorenz, Lars; Chudoba, T.; Makowski, Stefan; Zawischa, Martin; Schaller, F.W.; Weihnacht, Volker

doi:10.1007/s10853-021-06448-2

Cited by 19 publications

(11 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The mechanical properties of the pins were determined using a ZHN Nanoindenter (Zwick Roell, Germany) with a Berkovitch indenter. The QCSM module (quasi-continuous stiffness mode) was used to determine the indentation hardness at varying depths using a maximum of 50 mN load [25].…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Anomalous Wear Behavior of UHMWPE During Sliding Against CoCrMo Under Varying Cross-Shear and Contact Pressure

et al. 2022

View full text Add to dashboard Cite

Wear of ultra-high-molecular weight polyethylene (UHMWPE) in joint implant applications has been shown to increase with cross-shear (CS, i.e., multidirectional sliding) but decrease with higher contact pressure (CP). Moreover, structural changes, resulting in protrusions, are known to occur to the surface of the pin following multidirectional sliding. However, these phenomena are not yet fully understood. In this study, we simultaneously varied CP and CS to derive an empirical formula for the wear factor as a function of these parameters. The wear factor increased when going from unidirectional sliding to multidirectional sliding but decreased with increasing CP, as has been previously observed. Following these tests, the protrusions on the pin surface were chemically and mechanically characterized to gain insights into both their origin and influence on wear behavior. Micro-FT-IR confirmed that the structures consist of polyethylene, rather than adsorbed, denatured proteins. It also allowed the crystallinity of both the protrusions and unaffected UHMWPE to be estimated, showing a strong positive correlation with the hardness of these different areas on the surface. Time-of-flight secondary-ion mass spectrometry was used to probe the chemistry of the surface and near-surface region and indicated the presence of contamination from the test fluid within the structure. This suggests that the protrusions are formed by the folding of UHMWPE following plastic deformation. It is also suggested that the higher hardness of the protrusions affords some protection of the surface, leading to the observed anomalous behavior, whereby wear increases with decreasing CP. Graphical Abstract

show abstract

Section: Mechanical Propertiesmentioning

confidence: 99%

Anomalous Wear Behavior of UHMWPE During Sliding Against CoCrMo Under Varying Cross-Shear and Contact Pressure

et al. 2022

View full text Add to dashboard Cite

show abstract

“…For indentation, a Berkovich tip was used with a maximum load of 100 mN. The coating modulus was calculated as described in EN ISO 14577-4:216, using a sigmoid fit model for extrapolation of the Young’s modulus at the coating surface . After deposition, all coatings were lapped with a diamond slurry.…”

Section: Methodsmentioning

confidence: 99%

Surface Depassivation via B–O Dative Bonds Affects the Friction Performance of B-Doped Carbon Coatings

Peeters,

Kuwahara,

Härtwig

et al. 2024

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Boron doping of diamond-like carbon coatings has multiple effects on their tribological properties. While boron typically reduces wear in cutting applications, some B-doped coatings show poor tribological performance compared with undoped films. This is the case of the tribological tests presented in this work in which an alumina ball is placed in frictional contact with different undoped and B-doped amorphous carbon coatings in humid air. With B-doped coatings, a higher friction coefficient at a steady state with respect to their undoped counterparts was observed. Estimates of the average contact shear stress based on experimental friction coefficients, surface topographies, and Persson's contact theory suggest that the increased friction is compatible with the formation of a sparse network of interfacial ether bonds leading to a mild cold-welding friction regime, as documented in the literature. Tight binding and density functional theory simulations were performed to investigate the chemical effect of B-doping on the interfacial properties of the carbon coatings. The results reveal that OH groups that normally passivate carbon surfaces in humid environments can be activated by boron and form B−O dative bonds across the tribological interfaces, leading to a mild cold-welding friction regime. Simulations performed on different tribological pairs suggest that this mechanism could be valid for B-doped carbon surfaces in contact with a variety of materials. In general, this study highlights the impact that subtle modifications in surface and interface chemistry caused by the presence of impurities can have on macroscopic properties, such as friction and wear.

show abstract

“…A maximum load up to 25 mN was applied by the integrated Berkovich indenter (tip rounding < 150 nm) on sample surface using the quasi‐continuous stiffness method (QCSM). [ 46 ] At least 36 indentations were carried out on each foil, which were averaged for the extrapolation of indentation hardness and indentation modulus according to ISO 14577.…”

Section: Methodsmentioning

confidence: 99%

Understanding Substrate Mechanics and Chemo‐Mechanical Behavior of Columnar Silicon Films to Enable Deformation Free Anodes for High‐Energy Li‐Ion Batteries

Cangaz

Lohrberg

Abendroth

et al. 2023

Adv Materials Inter

View full text Add to dashboard Cite

Columnar silicon (col‐Si) is a great candidate as anode material to achieve volumetric energy density, outperforming state‐of‐the‐art lithium‐ion batteries. The utilization of col‐Si in industrial scale is mainly restricted by poor cyclic life originating from immense volumetric expansion of Si, resulting in mechanical failure of the electrode. Understanding the mechanic and breathing behavior of col‐Si films coupled with copper current collectors (Cu‐CC) is therefore crucial to mitigate the above‐mentioned issues. In this study, structure‐mechanical changes of col‐Si anodes, which are induced by stress evolution upon (de‐)lithiation of Si, are investigated via operando electrochemical dilatometry and in situ thickness monitoring on material and stack level depending on Cu‐CC thickness (10 and 18 µm) and state‐of‐charge/balancing factor (SoC / N/P ratio). Employing moderately thick Cu‐CC (18 µm) prohibits electrode deformation significantly, achieving energy densities of 1101 and 873 Wh L−1 in multilayered‐pouch cells for N/P ratios of 1.1 and 2.0, respectively. The volume uptake that takes place after the first cycle can strongly be reduced from ∆Vcell stack: 55% to 25% by adapting N/P: 2.0 instead of 1.1. Even after volumetric growth (lithiated state), energy densities around 700 Wh L−1 are still achievable, confirming the feasibility of the col‐Si approach.

show abstract

Indentation modulus extrapolation and thickness estimation of ta-C coatings from nanoindentation

Cited by 19 publications

References 14 publications

Anomalous Wear Behavior of UHMWPE During Sliding Against CoCrMo Under Varying Cross-Shear and Contact Pressure

Anomalous Wear Behavior of UHMWPE During Sliding Against CoCrMo Under Varying Cross-Shear and Contact Pressure

Surface Depassivation via B–O Dative Bonds Affects the Friction Performance of B-Doped Carbon Coatings

Understanding Substrate Mechanics and Chemo‐Mechanical Behavior of Columnar Silicon Films to Enable Deformation Free Anodes for High‐Energy Li‐Ion Batteries

Contact Info

Product

Resources

About