# Development of Thin Carbon-Ceramic Based Coatings in Roll-to-Roll Mode: Tribological and Corrosion Results on Stainless Steel

## TL;DR

Researchers developed carbon-ceramic coatings with graphene to improve the wear and corrosion resistance of stainless steel using roll-to-roll techniques.

## Contribution

A bilayer coating with tailored graphene content is proposed to balance tribological and corrosion properties.

## Key findings

- Higher graphene content reduces friction and wear but can worsen corrosion resistance due to aggregation.
- A bilayer coating with high graphene top layer and no graphene bottom layer optimizes performance.
- Roll-to-roll coating techniques were successfully applied for scalable production.

## Abstract

In this work, silicon oxide based coatings with embedded graphene nanoplatelets (content ranging from 1.8 wt.% to 7.2 wt.%) have been developed following the sol-gel route, using AISI430 stainless steel as substrate and dip and roll-to-roll as coating techniques. The tribological and corrosion behaviour of these coatings have been evaluated and compared to bare steel. Concerning tribological behaviour, the coefficient of friction and wear print were significantly reduced with increasing the graphene nanoplatelets content. Regarding corrosion, all coatings showed improved corrosion behaviour compared to bare steel. However, higher concentration of nanoplatelets revealed a negative effect on the corrosion resistance, probably due to aggregation. Taking into account these two counteracting effects, as final part of this work, a bilayer coating with different graphene content has been proposed and fabricated. A top layer, with high graphene nanoplatelets concentration has allowed enhanced tribological properties whereas bottom layer, with no graphene nanoplatelets assures corrosion inhibition under harsh environments.