# Investigating mechanical deformation’s role in cochlear implant durability

## TL;DR

This study examines how mechanical deformation affects the durability of platinum electrodes in cochlear implants.

## Contribution

The study reveals how microstructure and mechanical deformation influence platinum corrosion in cochlear implants.

## Key findings

- Corrosive attack on platinum surfaces occurred after three days of electrical stimulation.
- Mechanical deformation like rolling significantly impacts platinum's corrosion resistance.
- Grain size and surface defects affect electrochemical behavior unexpectedly.

## Abstract

Platinum and platinum-based alloys are used as the electrode material in cochlear implants because of the biocompatibility and the favorable electrochemical properties. Still, these implants can fail over time. The present study was conducted to shed light on the effects of microstructure on the electrochemical degradation of platinum. After three days of stimulation with a square wave signal, corrosive attack appeared on the platinum surface. The influence of mechanical deformation, in particular rolling, on the corrosion resistance of platinum was also prominent. The cyclic voltammetry showed a clear dependence on the electrolyte used, which was interpreted as an influence of the buffer in the artificial perilymph used. In addition, the polarization curves showed a shift with grain size that was not expected. This could be attributed to the defects present on the surface. These findings are crucial for the manufacture of cochlear implants to ensure their long-term functionality.