Influence of sol-gel coatings on crack initiation by vickers indentation in soda-lime glass

In this work an indentation technique was used to study the effect of the sol-gel coatings of soda-lime glasses on crack formation. The tendency of samples to develop radial cracks has been evaluated by measuring their number in correspondence with the Vickers impressions as a function of the applied load. Silica coatings of different thickness were obtained from alcoholic solutions of TEOS by the dipping technique on glass sheets with different degrees of surface hydration.

All the coated samples show a lower crackability compared with the uncoated ones. It was found that this parameter is influenced by layer thickness, heat treatment temperature and by the degree of galss surface hydration.