Stress–corrosion crack growth of Si–Na–K–Mg–Ca–P–O bioactive glasses in simulated human physiological environment

Abstract

This paper describes research on the stress-corrosion crack growth (SCCG) behavior of a new series of bioactive glasses designed to fabricate coatings on Ti and Co-Cr-based implant alloys. These glasses should provide improved implant fixation between implant and exhibit good mechanical stability in vivo. It is then important to develop an understanding of the mechanisms that control environmentally-assisted crack growth in this new family of glasses and its effect on their reliability. Several compositions have been tested in both static and cyclic loading in simulated body fluid. These show only small dependences of stress-corrosion crack growth behavior on the composition. Traditional SCCG mechanisms for silicate glasses appear to be operative for the new bioactive glasses studied here. At higher velocities, hydrodynamic effects reduce growth rates under conditions that would rarely pertain for small natural flaws in devices.

Mechanical properties of bioactive glass (13-93) scaffolds fabricated by robotic deposition for structural bone repair

“…However, in PBS at 37 °C, the mean fatigue life showed a significant decrease from 10 5.9 cycles to 10 4.2 cycles for the same increase in the stress amplitude. The observed trend for the effect of stress and aqueous environment on the fatigue of silicate 13–93 bioactive glass scaffolds is compatible with the stress corrosion crack growth mechanisms for bioactive and conventional silicate glasses [44] which is generally attributed to the stress corrosion of Si–O–Si bonds at the crack tip [45]. In normal walking, the compressive load on the human femur is estimated to be smaller than 4 times the body weight [46].…”

Interfaces in graded coatings on titanium‐based implants

“…In recent works, the possibility of fabricating glass or ceramic coatings on metallic alloys using different techniques2, 3 such as plasma spraying4, sol‐gel,5, 6 biomimetic process,7 magnetron sputtering,8 radiofrequency sputtering,8 electrophoretic deposition,9, 10 or a simple enameling technique11–17 among others such as dip coating, physical vapor deposition, ion‐beam, for instance, has been demonstrated. These graded glass layers can be modified by introducing calcium phosphate (CP) mixtures to control the dissolution rates.…”

Local surface damage and material dissolution in 45S5 bioactive glass: Effect of the contact deformation

“…A linear relation is observed between the crack-growth speed and the indentation load, which is in good accordance with Eq. (6). The result suggests the presence of the stress-assisted crack propagation in the 45S5 bioglass, when the indented 45S5 bioglass was immersed in the PBS solution.…”

“…Reis et al [5] observed the degradation of the hydroxyapatite coatings on Ti-6Al-4V substrate through surface cracking and faster dissolution when subjected to cyclic bending. Bloyer et al [6] evaluated the stress-corrosion crack growth of Si-based bioactive glasses in the SBF solution. Li et al [1] recently studied the stress effect on the material dissolution of 45S5 bioglass in the PBS solution using the Vickers indentation.…”