Friction-Wear Properties of Nickel-Free Co–Cr–Mo Alloy in a Simulated Body Fluid

Abstract

Friction-wear properties of a Co-29 mass%Cr-6 mass%Mo alloy (ASTM F799-95) but reducing the amount of nickel were evaluated with friction-wear test using a pin-on-flat type reciprocating friction tester in air and phosphate buffered saline, PBS(À), as a quasi-biological environment under applied stress of 1.0, 3.5 and 5.0 MPa to understand the performance of this alloy for metal-on-metal type artificial hip joints. In addition, metal ions dissolved in PBS(À) after the test was quantified. As a result, wear loss in PBS(À) is much smaller than that in air and increases with the increase of applied stress in both air and PBS(À), while the coefficient of friction in steady state during the test is larger in PBS(À) than in air, according to lubrication behavior of wear debris and PBS(À). Wear damage in PBS(À) is smaller than that in air, however more small scale of irregularity is observed in PBS(À) than that in air. Nickel and molybdenum are preferentially dissolved during the test.

A finite element study on the mechanical response of the head-neck interface of hip implants under realistic forces and moments of daily activities: Part 2

“…Comparing these findings with previous in-vitro tests, Swaminathan et al [14] applied greater magnitudes (contact stresses up to 1,100 MPa and a micro-motion of 50 µm) which may be found to be conservative. In another pin-on-disc study [6], the micro-motion was 25 µm which is well in the range of micro-motions suggested by the present work. Moreover, the contact stresses were only between 1 and 5 MPa, which are low compared to the contact stresses of up to 350 MPa reported in this work.…”

“…To date, many retrieval studies as well as in-vitro tests have been conducted to understand the occurrence and intensity of the fretting wear damage to the head and neck materials [4][5][6][7].…”

“…Maruyama et al. [6] performed pin-on-disc tests to study the fretting wear behaviour of a CoCr head and Although direct measurements of the mechanical environment are difficult, finite element (FE) analysis can be used to gain an understanding of the contact pressure and micro-motion throughout an activity [15][16][17]. The mechanical behaviour of the head-neck junction was investigated by Donaldson et al [18] using a stochastic finite element model.…”

Use of combination of accelerator-based ion-beam analysis techniques to the investigation of the corrosion behavior of CoCrMo alloy

“…However, their wear and corrosion stability are of great concern during the last years [1][2][3]. Literature studies showed that the released of metal ions (e.g.…”

Friction-Wear Properties of Nitrogen-Ion-Implanted Nickel-Free Co–Cr–Mo Alloy

“…The design of the instrument for the reciprocating friction test used in this study is shown in the previous study. 14) Both the pin and flat consisted of unimplanted and N 2þ -implanted Co-Cr-Mo alloys. The fixture for the pin also consisted of an unimplanted Co-Cr-Mo alloy to prevent galvanic corrosion.…”