PSI - Issue 18

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000–000 ScienceDirect

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 18 (2019) 538–548

25th International Conference on Fracture and Structural Integrity Effect of Zirconia ALD coating on stress corrosion cracking of AZ31 alloy in simulated body fluid Mirco Peron*, Jan Torgersen, Filippo Berto Department of Industrial and Mechanical Engineering, Norwegian University of Science and Technology, Richard Birkelands vei 2b, 7034 Trondheim, Norway Abstract In the last years, magnesium (Mg) and its alloys have been widely studied as materials for temporary implant devices. However, one of the main limitations that hampers its use in these applications is the occurrence of corrosion-assisted cracking phenomena, such as stress corrosion cracking (SCC) and corrosion fatigue (CF), in presence of the simultaneous action of corrosive human body-fluid and mechanical loadings. This work aims to provide some improvements in the field, assessing the effect of a 100nm thick zirconia coating produced by means of atomic layer deposition (ALD) on the SCC susceptibility of AZ31 alloy. Slow strain rate tests (SSRT) have been carried out with an applied strain rate equal to 2.6 10 -6 s -1 , and the samples were immersed in simulated body fluid at 37 °C for the whole duration of the tests. The presence of the coating has revealed to provide a reduction in the SCC susceptibility, measured by means of the I SCC indexes. In addition, to provide an explanation of the observed behavior, corrosion experiments (potentiodynamic polarization curves and hydrogen evolution experiments) have been carried out. 25th International Conference on Fracture and Structural Integrity Effect of Zirconia ALD coating on stress corrosion cracking of AZ31 all y in simulated body fluid Mirco Peron*, Jan Torgersen, Filippo Berto Department of Industrial and Mechanical Engineering, Norwegian University of Science and Technology, Richard Birkelands vei 2b, 7034 Trondheim, Norway Abstract In t e la t years, magnesium (Mg) and its alloys have been widely studied as materials for temporary implant devices. However, one of the main limit tions th t hampers its use in these applications is the ccurrence of corrosion-as isted cracking phenome a, such as stress rrosion cracking (SCC) and c rrosion fatigue (CF), in prese ce of the simultaneous action of corrosive hum n body-fluid and mechanical loadings. This work aims to provide some improvements i the field, as essing the ff ct of a 100nm thick zirconia coating produced by means f atomic layer deposition (ALD) on the SCC susc ptibility of AZ31 alloy. Slow strain rate tests (SSRT) have been carried ut with an appli d strain rate equal t 2.6 10 -6 s -1 , and the samples were imm rsed in simulated body fluid at 37 °C f r the whole duration of the tests. The presence of the coating has revealed to provide a reduction in the SCC susceptibility, measured by means of the I SCC indexes. In addition, to provide an explanation of the observed behavior, corrosion experiments (potentiodynamic polarization curves and hydrogen evolution experiments) have been carried out.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. P er-review under respon ibility f the Gruppo Italiano Frattura (IGF) ExCo. Keywords: AZ31 alloy; Stress corrosion cracking; Atomic layer deposition

Keywords: AZ31 alloy; Stress corrosion cracking; Atomic layer deposition

1. Introduction During the past years life expectancy has been continuously increasing, leading to an incessant growth of people undergoing surgical procedures involving the implantation of medical devices (Ginebra, Traykova, and Planell 2006). In particular, orthopaedic surgery is the most important (Bradley and Harrison 2004; M. Long and Rack 1998), and it is characterized by the highest annual growth rate (P. H. Long 2008). The materials currently used in orthopaedic 1. Introduction During the past years life expectancy has been continuously increasing, leading to an incessant growth of people undergoing surgical procedures involving the implantation of medical devices (Ginebra, Traykova, and Planell 2006). In particular, orthopaedic surgery is the most important (Bradley and Harrison 2004; M. Long and Rack 1998), and it is characterized by the highest annual growth rate (P. H. Long 2008). The materials currently used in orthopaedic

* Corresponding author. Tel.: +4748280157 E-mail address: mirco.peron@ntnu.no

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. * Corresponding author. Tel.: +4748280157 E-mail address: mirco.peron@ntnu.no

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2019.08.198