Influence of Boron Addition on the Microstructure and the Corrosion Resistance of CoCrMo Alloy

Abstract

Cobalt-based alloys are extensively used in orthopedic applications for joint replacements due to their wear and corrosion resistance. Corrosion, however, is often associated with fatigue failure in these orthopedic devices. In this study, the effect of boron addition on the corrosion behavior of CoCrMo alloys was studied using linear polarization resistance, potentiodynamic polarization curves, electrochemical impedance spectroscopy, and cyclic voltammetry. The samples were analyzed under as-cast and heat treatment conditions after 21 days of immersion in phosphate-buffered saline (PBS) solution at 37 °C. The boron addition increased the particle content, while the heat treatment promoted enlargement and even distribution of the precipitates throughout the structure. The corrosion resistance was improved by both boron and heat treatments. The best performance was observed for a heat-treated alloy having a very small amount of boron, which had an increased resistance to corrosive attack. Such behavior was attributed to the homogenized microstructure achieved by boron and heat treatment that helped to form a stable passive layer of chromium oxide which endured the 21 days of immersion.

Influence of Boron Additions and Heat Treatments on the Fatigue Resistance of CoCrMo Alloys

“…The highest resistance to crack growth was also observed under this material condition. In a previous study, this alloy also showed good corrosion resistance [20]. The dark areas in some overview pictures were coloured with ink to identify certain areas during observations using scanning electron microscopy.…”

“…The specific objective of this study is to assess the fatigue performance of these alloys under both as-cast and heat-treated conditions. It is worth mentioning that these alloys were also evaluated in corrosion resistance [20].…”

CoCrMo alloy as biomaterial for bone reconstruction in oral and maxillofacial surgery: A scoping review.

“…It clearly proves that by forcing the passive film and organometallic complexes to form, wear, corrosion and tribocorrosion resistance of materials could be improved. Bedolla, 52 Rodriguez-Castro 53 and Hernandez-Rodriguez et al, 54 found that the boron addition improved the wear resistance by refinement in grain size and a homogeneous distribution of hard precipitated along the matrix. Additionally, other authors have investigated the effect of surface treatments such as diamond-like carbon (DLC), 55-57 carbon ion implantation 58 and TiO 2 coating 59, 60 on CoCrMo alloys to reduce the corrosion of implant alloys, obtaining good results.…”

Impact of Pretreatment of Metal Glass Fe70Cr15B15 on Anodization in 1-butyl-3-methylimidazolium Tetrafluoroborate Ionic Liquid

“…One of the most attractive properties of these materials is their corrosive resistance in aqueous solutions. Therefore, the alloy corrosion resistance was improved by the increase in the boron content [8].…”