Local pH and oxygen concentration at the interface of Zn alloys in Tris-HCl or HEPES buffered Hanks' balanced salt solution. (1st April 2022)

• Record Type: Journal Article
• Authors: Wang, Cheng; Liu, Xiao; Mei, Di; Deng, Min; Zheng, Yufeng; Zheludkevich, Mikhail L.; Lamaka, Sviatlana V.
• Is Part Of: Corrosion science. Volume 197(2022)
• Publication Date: 2022-04-01
• Subjects: Local pH -- Local oxygen concentration -- Tris-HCl -- HEPES -- Biodegradable Zn-based alloy -- Hanks' balanced salt solution; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2021.110061
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: Although Tris-HCl and HEPES are typically used pH buffers for in vitro studies, they are recently proven to be unable to stabilize local pH at Mg interface in simulated body fluids. In this study, local pH close to physiological (7.1–7.5) was found at metal/fluid interface of pure Zn, Zn-0.8 wt%Ca and Zn-0.8 wt%Mg alloys in Tris-HCl or HEPES buffered Hanks' balanced salt solution (HBSS) at 37 °C under hydrodynamic conditions. High rate oxygen consumption was detected above Zn alloys in various HBSS electrolytes. These findings support the previous recommendation of using synthetic pH buffers for in vitro studies of biodegradable Zn-based alloys. Highlights: Local pH and O2 level were recorded at Zn-alloys interfaces in varied HBSS at 37 °C. Local pH at metal interface was buffered at 7.1–7.5 in HBSS with Tris-HCl or HEPES. High rate O2 consumption was detected at the interface of Zn alloys in various HBSS. Tris-HCl or HEPES undermined the barrier property of Ca-P-containing products layer. Low rate H2 evolution was detected in corrosive pits on corroding Zn alloys in HBSS.