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

The objective of this work was to investigate the low cycle tribological and tribocorrosion characteristics of AM CoCrMoW alloys compared to wrought LC CoCrMo (ASTM F-1537) to assess this AM alloy's performance. Fretting and tribocorrosion testing was performed in air (wear only), PBS (wear  + corrosion), and PBS with 10 mM H2O2 (wear  + corrosion + inflammation) by a single diamond asperity. No variation between alloys in volume of material removed (p = .12), volume of plastic deformation (p = .13), and scratch depth (p = .84) showed that AM was substantially similar in wear resistance to LC in air and PBS. AM exhibited significantly higher fretting currents (p <  .01) at loads up to 100 mN (IAMPBS$$ {I}_{\mathrm{AM}}^{\mathrm{PBS}} $$ = 57 nA and IAMH2O2$$ {I}_{\mathrm{AM}}^{H_2{O}_2} $$ = 49 nA) than LC CoCrMo (ILCPBS$$ {I}_{\mathrm{LC}}^{\mathrm{PBS}} $$ = 30 nA) and (ILCH2O2$$ {I}_{\mathrm{LC}}^{H_2{O}_2} $$ = 29 nA). In PBS, wear track depth linearly correlates to fretting current, averaged over 100 cycles. Additionally, fretting currents of both alloys were significantly lower in simulated inflammatory conditions compared to PBS alone. AM alloy has generally similar wear and tribocorrosion resistance to wrought LC Co CrMo and would be ideal for patient specific dentistry or orthopedics where precise, complex geometries are required.
Source: Journal of Biomedical Materials Research Part B: Applied Biomaterials - Category: Materials Science Authors: Tags: RESEARCH ARTICLE Source Type: research