Enhanced wear resistance of engineered glass-ceramic by nanostructured self-lubrication

V Fuertes,M.J Cabrera,J Seores,D Muñoz,J.F Fernández,E Enríquez

doi:10.1016/j.matdes.2019.107623

V Fuertes, M.J Cabrera + Show 4 more

Open Access

https://doi.org/10.1016/j.matdes.2019.107623

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Abstract

A new kind of micro-nanostructured glass-ceramic based on albite and anorthite crystallizations, >90%, has been obtained following a fast sintering processing route. Flexural strength values up to 111 MPa and microhardness values of 9.5 GPa are measured, supposing an improvement of ~60% regarding current glazes for ceramic floor tiles for high transit areas. The hierarchical micro-nanostructuration of these glass-ceramics favour crack deflection, which implies a reduction of brittleness in these materials and a consequent increase of fracture toughness of ~40% regarding a standard glass-ceramic. Tribological properties are also evaluated, showing a decrease in the friction coefficient (μ) of ~36% and a surprising reduction of the wear rate (WR) larger than one magnitude order, in both micro-nanostructured glass-ceramics, concerning a standard one. Worn tracks analysed by Multi-Mode Optical Profilometry and FE-SEM measurements revealed that nanocrystals present in the microstructure work as solid lubricants, favouring body sliding over their surface and noticeably reducing μ, WR and the surface damage suffered. Wear mechanism undergone by both glass-ceramics is unlike other glass-ceramics, similar to a polishing process, without any apparent material spalling. All of these findings make the micro-nanostructured materials very promising candidates to be used in high-performance self-lubricating applications.

Highlights

A new glass-ceramic family with high crystallinity and a unique micro-nanostructure has been successfully designed. These engineered glass-ceramics results in a simultaneous improvement of flexural strength, microhardness, fracture toughness and tribological properties regarding standard materials used in tile industry
These novel materials show the highest microhardness reported for a glaze, up to 9.5 GPa, which supposes an enhancement of ~60% in relation to a traditional floor tile glaze and ~7% regarding the best reported value in literature for a glass-ceramic material
The hierarchical micro-nanostructuration of these glass-ceramics favours crack deflection, which implies a reduction of brittleness and a consequent increase of fracture toughness of ~40% regarding a standard glass-ceramic

Summary

Introduction

V. Fuertes et al / Materials and Design 168 (2019) 107623 good mechanical properties (e.g machinability, high hardness and high resistance to abrasion) [1]. Standard glazes have low abrasive resistance and loses its surface characteristics, such as brightness, colour and superficial texture [10]. To overcome these drawbacks in the ceramic tile industry, new engineered products showing better resistance to wear by abrasion and higher surface hardness than traditional glass-ceramics are required [10,11,12,13]

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