Microstructure‐dependent crevice corrosion damage of implant materialsCoCr28Mo6,TiAl6V4andREX734 under severe inflammatory conditions

Abstract

Fretting corrosion is associated with increased risk of premature implant failure. In this complex in vivo corrosion system, the contribution of static crevice corrosion of the joined metal alloys is still unknown. The aim of this study was to develop a methodology for testing crevice corrosion behavior that simulates the physiological conditions of modular taper junctions and to identify critical factors on corrosion susceptibility. Samples of medical grade CoCr28Mo6 cast and wrought alloy, TiAl6V4 wrought alloy and REX 734 stainless steel were prepared metallographically and the microstructure was investigated using scanning electron microscopy (SEM). Crevice formers that mimic typical geometries of taper junctions were developed. Crevice corrosion immersion tests were performed in different physiological fluids (bovine serum or phosphate buffered saline with additives of 30 mM H 2 O 2 at pH = 1) for 4 weeks at 37 C. SEM with energy dispersive X-ray spectroscopy as well as focused ion beam were used to characterize the surface morphology, investigate present damages and identify the chemical composition of residues. Macroscopic inspection showed increased crevice corrosion susceptibility of TiAl6V4 and REX 734 under severe simulated inflammatory conditions. CoCr28Mo6 cast alloy exhibited degraded areas next to Cr-and Mo-rich precipitations that were located within the opposed crevices. The results indicate that aggressive electrolyte composition and crevice heights of 50-500 μm are critical influencing factors on crevice corrosion of biomedical alloys. Furthermore, manufacturing-related microstructure of common implant alloys determines the deterioration of corrosion resistance. The developed method should be used to enhance the corrosion resistance of common implant biomaterials by an adapted microstructure.

A feasibility study of promoting osseointegration surface roughness by micro-milling of Ti-6Al-4V biomedical alloy

“…Finally, it is characterized by a high fatigue strength, mandatory in the cyclic load at which the human body is subjected [3]. However, Herbster et al [26] demonstrated its sensitivity to fretting corrosion, giving an abrasion of the TiO 2 layer that is faster than its repassivation, increasing its susceptibility to fatigue crack initiation. The first group of Ti-6Al-4V specimens employed consisted of those in the supplied state, hereafter named as-received, of bars with a diameter of 20 mm resulting from a hot plastic deformation process.…”

The Year 2022 in biomaterials research: A perspective from the editors of six leading journals

“…Studies of the interplay of degradation products in orthopedic alloys and the body were also a focus. Ongoing concerns related to CoCrMo alloys and the corrosion and wear products were evaluated [87][88][89] including fretting corrosion of modular taper junctions, 90 the effects of chromium degradation products, 90 mixed metal degradation products 89 and crevice corrosion of orthopedic alloys. 87 Three-dimensional printing of soft biomaterials, biomaterial-celldrug combinations and 3D printing of hard biomaterials have all seen increased attention in the past year.…”

“…Ongoing concerns related to CoCrMo alloys and the corrosion and wear products were evaluated [87][88][89] including fretting corrosion of modular taper junctions, 90 the effects of chromium degradation products, 90 mixed metal degradation products 89 and crevice corrosion of orthopedic alloys. 87 Three-dimensional printing of soft biomaterials, biomaterial-celldrug combinations and 3D printing of hard biomaterials have all seen increased attention in the past year. These works have investigated the range of 3D printing from electron-beam printing of titaniumbased spinal cages 91 to 3D printing of Hydroxyapatite and/or polymeric hydrogel biomaterials.…”

Interaction pathways of implant metal localized corrosion and macrophage inflammatory reactions

“…The cell-accelerated corrosion of CoCrMo alloy was also detected under the inflammatory chemical environment generated by particle-stimulated macrophages [ 15 ]. The inflammatory species such as H 2 O 2 , HOCl generated by inflammatory cells can drive the corrosion of implant alloys [ [40] , [41] , [42] ]. The metabolism, adhesion and bioelectricity of inflammatory cells may also regulate the corrosion of metallic implants [ [43] , [44] , [45] ].…”