Work

In Vitro Corrosion Resistance and Mechanical Properties of Ag-SiO2-TiO2 Coatings Electrophoretically Deposited on NiTi Alloy

Year: 2025

Type: article

Abstract: NiTi alloys are widely used in biomedical applications due to their shape memory and superelastic properties. However, their surface reactivity requires protective, biofunctional coatings. To enhance NiTi performance, its surface was modified with an Ag-SiO2-TiO2 nanocoating containing small amounts of silica and silver. The coating’s primary phase was rutile with structural defects and a silver solid solution. It showed good adhesion, high scratch resistance, and improved corrosion behavior in Ringer’s solution, as demonstrated by EIS and cyclic polarization. EIS revealed high low-frequency impedance and two time constants, suggesting both barrier protection and slower electrochemical processes. Despite low breakdown and repassivation potentials, the coating effectively limited uniform corrosion. SEM/EDS confirmed localized degradation and partial substrate exposure, while elemental mapping showed well-dispersed silica and silver in a TiO2-rich matrix. The proposed pitting mechanism involves chloride-induced depassivation and galvanic effects. Surface potential mapping indicated electrostatic heterogeneity, mitigated by silica. The coating offers a balanced combination of corrosion protection and biofunctionality, supporting its potential for implant use.

Source: Coatings

DOI: 10.3390/coatings15101176

Authors: Bożena Łosiewicz, Julian Kubisztal, Adrian Barylski, Karolina Dudek

Institutions: University of Silesia in Katowice, Łukasiewicz Research Network, Institute of Ceramics and Building Materials

Language: English

Topic: Titanium Alloys Microstructure and Properties

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $3,137