Micro-asperity tribocorrosion of CoCrMo, Ti6Al4V, and 316 stainless steel in air and physiological solution: Small scale reciprocal sliding of a single diamond tip

Low cycle fretting and fretting corrosion properties of low carbon CoCrMo and additively manufactured CoCrMoW alloys for dental and orthopedic applications

“…This phenomenon of shortlived fretting contact engagements of asperities generating the same levels of penetration in just a few 100 cycles as levels of damage seen after years of cyclic loading of large-scale load bearing devices is explained by Mace and Gilbert, 2022. 14 Single asperity measurements thus provide the same level of damage in just a few seconds as could only be achieved by an in vitro cyclic loading test over weeks/months of simulating walking at the clinically comparable frequencies (3 Hz) that are used by Mace and Gilbert, 2022. 14 Thus, a single, inert diamond asperity as the counter surface and short-term abrasion experiments provide a systematic comparison of tribology resistance, as well as fretting corrosion resistance, of metallic biomaterials.…”

“…14 Single asperity measurements thus provide the same level of damage in just a few seconds as could only be achieved by an in vitro cyclic loading test over weeks/months of simulating walking at the clinically comparable frequencies (3 Hz) that are used by Mace and Gilbert, 2022. 14 Thus, a single, inert diamond asperity as the counter surface and short-term abrasion experiments provide a systematic comparison of tribology resistance, as well as fretting corrosion resistance, of metallic biomaterials. Additionally, because AM CoCrMoW alloys are designed for implantation into oral cavities subject to both aqueous and acidic, as well as abrasive factors, it is important to also assess the performance of the passive oxide layer of AM CoCrMoW in such destructive environments.…”

“…Fretting testing was performed using a single diamond stylus with a radius of 17 μm attached to a custom-built load cell capable of producing cyclic fretting scratches in air (fretting). 14,15 The load cell was controlled with a motor to provide the appropriate load, and a piezoelectric actuator (Modular Piezo controller System ENV, piezosystem jena, Inc., Hopedale, MA) along with a function generator (SFG-210, Global Specialties, Yorba Linda CA) controlled the horizontal fretting movement. Cyclic fretting tests were performed for 100 cycles at 3 Hz under various loads from <10 to 100 mN (nominal stresses just above the hardness).…”

“…13 While the true area of contact of such devices is comprised of micron-scale multi-asperity contacts, using a single-asperity simulates one such contact interaction as the abrading body to provide a more controllable, systematic, and measurable method of degradation. 14 These contact interactions may only last a short time before new asperityasperity contacts develop and degrade. This phenomenon of shortlived fretting contact engagements of asperities generating the same levels of penetration in just a few 100 cycles as levels of damage seen after years of cyclic loading of large-scale load bearing devices is explained by Mace and Gilbert, 2022.…”

“…As AM alloys are further introduced and gain popularity for use in medical devices, the fretting corrosion and degradation mechanisms of these alloys, compared to traditional alloys are important to understand, as metal on hard or metal on metal contacts are prevalent in these devices 13 . While the true area of contact of such devices is comprised of micron‐scale multi‐asperity contacts, using a single‐asperity simulates one such contact interaction as the abrading body to provide a more controllable, systematic, and measurable method of degradation 14 . These contact interactions may only last a short time before new asperity‐asperity contacts develop and degrade.…”