SIPS 2018

DETAILLED PROGRAM OVERVIEW

Novel Biocompatible Ni- and Cu-free Ti-based Amorphous Alloys: Thermal Stability, Corrosion Resistance and Apatite-forming Ability
Mariana Calin¹; Somayeh Abdi¹; Juergen Eckert²; Annett Gebert¹;
¹IFW DRESDEN, Dresden, Germany; ²ERICH SCHMID INSTITUTE OF MATERIALS SCIENCE, Leoben, Austria;
PAPER: 30/SISAM/Invited (Oral)
SCHEDULED: 18:05/Wed./Copacabana A (150/1st)

ABSTRACT:
Metallic glasses, also known as amorphous alloys or liquid metals, are relative newcomers in the field of biomaterials. They have gained increasing attention during the past decades, as they exhibit an excellent combination of properties and processing capabilities desired for versatile biomedical implant applications [1]. In the present study, we developed new Ti-based glassy alloys without any harmful additions, with potential for orthopaedic and dental applications. Ti75Zr10Si15 and Ti60Nb15Zr10Si15 glassy alloys were obtained by melt spinning and their crystallization behavior, corrosion resistance, and apatite-forming ability were investigated [2,3]. These compositions are marginal glass formers and cannot lead to bulk glass formation. Upon devitrification on heating, the Ti-(Nb)-Zr-Si glassy alloys exhibit nanophase composite microstructures, which lead to a remarkable improvement of mechanical properties. The corrosion and passivation behavior of the alloys in their homogenized melt spun states in Ringer solution at 37°C in comparison to their cast multiphase crystalline counterparts and to cp-Ti and beta-type Ti-40Nb was studied. All tested materials showed very low corrosion rates as expressed in corrosion current densities icorr<50 nA/cm2. Electrochemical and surface analytical studies revealed a high stability of the new alloys passive states in a wide potential range. The addition of Nb does not only improve the glass-forming ability and the mechanical properties, but also supports a high pitting resistance even at extreme anodic polarization. With regard to the corrosion properties, the Nb-containing glassy alloy can compete with the beta-type Ti-40Nb alloy. Simulated body fluid (SBF) tests confirmed the ability for formation of hydroxyapatite on the melt-spun alloy surfaces. All these properties recommend the new glass-forming alloys for applications as wear- and corrosion-resistant coating materials for implants.

References:
[1] A.L. Greer, Materials Today, 12 (2009) 14
[2] M. Calin et al., Mat. Sci. Eng. C, 33 (2013) 875
[3] S. Abdi et al., J. Biomed. Mat. Res. B, 104 (2016) 27.