Properties and Corrosion Performance of Self-reinforced Composite PEEK for Proposed Use as a Modular Taper Gasket

Abstract

Background Fretting corrosion in medical alloys is a persistent problem, and the need for biomaterials that can effectively suppress mechanically assisted crevice corrosion in modular taper junctions or otherwise insulate metalon-metal interfaces in mechanically demanding environments is as yet unmet. Questions/purposes The purpose of this study is to characterize a novel material, self-reinforced composite polyetheretherketone (SRC-PEEK) and to evaluate its ability to inhibit fretting corrosion in a pin-on-disk metalon-metal interface test.Methods SRC-PEEK was fabricated by hot compaction of in-house-made PEEK fibers by compacting uniaxial layups at 344°C under a load of 18,000 N for 10 minutes. SRC-PEEK, bulk isotropic PEEK, and the in-house-made PEEK fibers were analyzed for thermal transitions (T g , T m ) through differential scanning calorimetry, crystallinity, crystal size, crystalline orientation (Hermanns orientation parameter) through wide-angle x-ray scattering, and modulus, tensile strength, yield stress, and strain to failure through monotonic tensile testing. SRC-insulated pin-ondisk samples were compared with metal-on-metal control samples in pin-on-disk fretting corrosion experiments using fretting current and fretting mechanics measurements. Fifty-micron cyclic motion at 2.5 Hz was applied to the interface, first over a range of loads (0.5-35 N) while held at À0.05 V versus Ag/AgCl and then over a range of voltages (À0.5 to 0.5 V) at a constant contact stress of 73 ± 19 MPa for SRC-PEEK and 209 ± 41 MPa for metal-onmetal, which were different for each group as a result of changes in true contact area due to variations in modulus between sample groups. Pins, disks, and SRC samples were imaged for damage (on alloy and SRC surfaces) and evidence of corrosion (on alloy pin and disk surfaces). SRC specimens were analyzed for traces of alloy transferred to the surface using energy dispersive spectroscopy after pinon-disk testing.

Interfacial compliance, energy dissipation, frequency effects, and long‐term fretting corrosion performance of Ti‐6Al‐4V/CoCrMo interfaces

“…Previous studies of compliant interfaces have shown successful reductions in metal surface damage during simulated tribocorrosion conditions 20,22 . This study of long‐term fretting corrosion performance was done to determine the viability of such a design as it relates to modular taper junction applications over prolonged fretting conditions.…”

“…The calculated R ox and Q ox parameters for all groups after 1 million fretting cycles are plotted against one another using a 20,22 This study of long-term fretting corrosion performance was done to determine the viability of such a design as it relates to modular taper junction applications over prolonged fretting conditions. Increased interfacial compliance kept surfaces stable and locked in place, but surfaces were not without damage, although the damage was diminished with higher compliance interfaces.…”

“…In terms of implant materials and design, methods for reducing fretting corrosion damage in a modular junction must address one or more of its causes, ideally without eliminating modularity. Potential solutions include preventing fluid from entering the junction, insulating the metal surface(s) against oxide abrasion and corrosion processes, or preventing micromotion at the interface during loading 20 . While preventing fluid ingress into a crevice is challenging in a biological environment, Ouellette and Gilbert have shown significant improvements in fretting corrosion performance in metal‐on‐metal hip replacement devices with the use of a compliant, low‐modulus, low‐hardness PEEK layer fitted at the head–neck taper junction 21 .…”

“…Potential solutions include preventing fluid from entering the junction, insulating the metal surface(s) against oxide abrasion and corrosion processes, or preventing micromotion at the interface during loading. 20 While preventing fluid ingress into a crevice is challenging in a biological environment, Ouellette and Gilbert have shown significant improvements in fretting corrosion performance in metal-on-metal hip replacement devices with the use of a compliant, low-modulus, low-hardness PEEK layer fitted at the head-neck taper junction. 21 Similarly, micromotion can be minimized, if not prevented, at the interface with geometric modifications that alter the contact conditions between surfaces, allowing individual contact points to elastically deform during fretting instead of sliding.…”

Recent advances in biopolymeric composite materials: Future sustainability of bone-implant

“…AM techniques with this type of material allow obtaining porous structures that reduce the elastic modulus, and parameters similar to the bone can be obtained. In this sense, the most widely used technologies for obtaining porous structure-based titanium are those based on sintering processes, such as electron beam melting or selective laser melting [93][94][95][96]. Recently, the introduction of nano-HAp as an additive of these alloys has been proposed to obtain potentially more bioactive structures than the usual titanium-based metal alloys.…”