Fretting-corrosion between 316L SS and PMMA: Influence of ionic strength, protein and electrochemical conditions on material wear. Application to orthopaedic implants

Abstract

In biomedical field, fretting-corrosion between 316L SS femoral stem and bone cement is one of the significant causes of the hip prosthesis loosening. This article investigates wear by fretting-corrosion at the contact between 316L and PMMA . The influences of the ionic strength (NaCl solutions from 10 -3 to 1 mol.L -1 ), a model protein (albumin) and electrochemical conditions on contact behaviour are studied. At OCP (Open Circuit Potential) conditions, the chlorides concentration, i.e. the ionic strength, increases the 316L wear; and albumin, concentration of 1g.L -1 , does not play a significant role in total 316Lwear. At cathodic applied potential E = -400 mV(SCE), a threshold concentration of 10 -1 mol.L -1 (NaCl solution), C th , indicates two behaviours: a protective effect below C th , and an additional anodic dissolution above C th . One might suggest that, beyond C th , the passive layer is not efficient for protecting against the corrosion. At this potential, albumin reduces wear due to corrosion and amplifies mechanical wear induced by corrosion. Albumin seems to act as an anodic inhibitor. To determine the mechanisms of synergism, a "more cathodic" potential is applied, E = -800 mV(SCE), during fretting-corrosion experiments.Consequently, the corrosive wear can be neglected and the mechanical wear can be only measured.

Prévision de l'épaisseur du film passif d'un acier inoxydable 316L soumis au fretting corrosion grâce au Point Defect Model, PDM

“…L'approche expérimentale du fretting corrosion est décrite dans [4,5]. De ces investigations des résultats ont eté obtenus sur l'influence de la concentration de chlorure avec une certaine teneur de protéines, i.e.…”

“…Lesépaisseurs modélisées et les faits expérimentaux Ainsi lesépaisseurs de films d'oxydes et les faits expérimentaux tendentà montrer que l'albumine protège l'acier inoxydable 316L contre les dégradations par fretting corrosion. Les faits expérimentaux ontété mis enévidence dans [5]. …”

“…Comme indiqué précédemment, même si le métal a de meilleures performances mécaniques que celles de l'os, en fretting corrosion l'usure de l'acier inoxydable est plus grande que celle du polymère, pourtant beaucoup moins dur que l'acier inoxydable. Avant d'entreprendre des tests très proches des conditions réelles de sollicitation des prostheses totals de hanche, avec notamment la prise en compte du milieu physiologique complexe, des tests entre l'acier inoxydable 316L et le Polyméthacrylate de méthyle (PMMA) ontété entrepris ; ces matériaux ont des caractéristiques mécaniques très proches de celles des implants orthopédiques et de l'os [4,5]. Plusieurs résultats intéressants ontété fournis par des tests expérimentaux et les auteurs impliqués dans ce travail souhaitent apporter de nouvelles connaissances en utilisant une modélisation basée sur le Point Defect Model [6][7][8].…”

The role of surface pre-treatment on the microstructure, corrosion and fretting corrosion of cemented femoral stems

“…It is only of late that the tribocorrosion degradation, described as material loss owing to mechanical and electrochemical reactions, and the factors influencing this have been considered for cemented devices [8][9][10][11][12].…”

“…Although the wear mechanisms acting at the stem-cement interface are fairly well accepted, they tend to be lesser known and assumed when compared to bearing or taper interfaces. Currently only a few studies exist investigating the role of fretting-corrosion and the influence of system variables at the stem-cement interface [8,14,11,15]. Recently the authors have presented systematic work outlining the tribocorrosion mechanisms [15,13] and role of system variables such as cement type [16,17] and mixed metal couples [18] on the overall degradation of cemented femoral stems.…”