Tribocorrosion of passive metals in the mixed lubrication regime: theoretical model and application to metal-on-metal artificial hip joints

Shoufan Cao, Stefano Mischler
Elsevier, 2015
Article

Wear is a key problem limiting the lifetime and performance of total hip arthroplasty. The synovial fluid, acting as lubricant, can alleviate the wear of implants but also introduces corrosion. The interaction of mechanical wear and electrochemical corrosion, nominally tribocorrosion, has been proposed as one of the crucial degradation mechanisms of implants and recently saw significant progress in mechanistic understanding and modeling. This study presents a predictive wear model based on a mechanistic approach of tribocorrosion and lubrication and taking into account clinical relevant parameters such as normal load, velocity and clearance. Predicted wear rate corresponds well to the running-in wear rate from simulator experimental results and allows to identify the dominating wear mechanism and to evaluate the influence of several parameters. (C) 2014 Elsevier B.V. All rights reserved.

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Concepts associés

Chargement

Publications associées

Chargement

Shoufan Cao, Stefano Mischler
Elsevier, 2015
Article

Résumé

Official source

https://infoscience.epfl.ch/record/208512?ln=fr

À propos de ce résultat

Concepts associés (10)

Concepts associés

Chargement

Publications associées (8)

Publications associées

Chargement

Corrosion

La corrosion désigne l'altération d'un matériau par réaction chimique avec un oxydant (le dioxygène et le cation H+ en majorité). Il faut en exclure les effets purement mécaniques (cela ne co

Usure des surfaces

Dans la science des matériaux, l'usure des surfaces désigne le phénomène de dégradation des couches superficielles d'un solide sous l'action mécanique du milieu extérieur. Cette dégradation est souve

Droits et libertés

La notion de droits et libertés est une théorie en philosophie du droit naturel désignant l'ensemble des normes par lesquelles une personne ou un groupe jouit d'un pouvoir d'autogouvernance. Défini

A lubricated tribocorrosion model incorporating surface roughness

Shoufan Cao, Stefano Mischler

This study presents an improvement of an existing tribocorrosion model developed for passive CoCrMo alloys. This model is based on an empirical formalism established by Duncan Dowson in his pioneering works on the relation between wear and elasto-hydrodynamic lubrication. The improvement consists in introducing surface topography features allowing for a mechanistic relation between lubrication and wear. The effective normal force accounting for the plastic deformation of passive metals during lubricated tribocorrosion was described through the real contact area, which in turn was related to the worn surface topography (roughness) and the elasto-hydrodynamic film thickness. The modified model was applied to results from dedicated tribocorrosion experiments obtained by varying the lubricant viscosity and the contacting surface roughness. Good correlations were found between the mechanical and chemical wear rates and corresponding variables, which validated the model. Further development of the model should include boundary film effects, third bodies build-up and time dependent evolution of the worn surface.

2021

Chargement

Influence of Bovine Serum Albumin (BSA) on the Tribocorrosion Behaviour of a Low Carbon CoCrMo Alloy in Simulated Body Fluids

Shoufan Cao, Stefano Mischler, Choshun Yoneyama

Tribocorrosion, as the interaction between mechanical wear and electrochemical corrosion, has been found to be the main problem causing the failure and limiting the lifetime of metal-on-metal artificial hip joints. Better understanding of the tribocorrosion mechanisms of CoCrMo alloys is needed in order to reduce the degradation of this alloy, especially in the presence of proteins as one of the organic components present in synovial fluid. In this study, tribocorrosion tests of a low carbon CoCrMo alloy in phosphate buffer solution (PBS) with and without bovine serum albumin (BSA) in two different concentrations at different applied potentials (passive and cathodic) were carried out. The results show that the effect of proteins on wear and friction was concentration and potential dependent. In the cathodic domain (absence of very thin passive film), wear was very low in all solutions and the friction was significantly reduced by the addition of BSA to PBS even at low BSA concentrations. However, in the passive domain, the friction and wear were found not to be affected when the BSA concentration was 0.5 g/L, while they were reduced when increasing the BSA concentration to 36 g/L. The tribocorrosion results were rationalized through an existing tribocorrosion model and the effect of BSA on wear and friction was explained by the consideration of physical factors such as changes in viscosity and double layer structure, because in the present results no tribofilm formation was observed.

2020

Chargement

Triboelectrochemical techniques and interpretation methods in tribocorrosion: A comparative evaluation

Stefano Mischler

Tribocorrosion is a material deterioration or transformation resulting from simultaneous action of wear and corrosion. Tribocorrosion is found in many engineering applications but the involved mechanisms are still little understood. The investigation of tribocorrosion requires the control of the chemical conditions during a wear test. In aqueous electrolytes, this is achieved by using different types of electrochemical-controlled wear experiments (triboelectrochemical experiments). This paper presents a critical appraisal of the main electrochemical techniques and evaluation methods used in tribocorrosion research with special emphasis on sliding and fretting situations involving passive metals. (c) 2007 Elsevier Ltd. All rights reserved.

2008

Chargement