Surface‐Localized Intrinsic Toughening of Glass With Preserved Transparency by Ni Nanoparticle Precipitation

To overcome the brittleness of glass, many intrinsic toughening approaches have been proposed. Recently, incorporation of metallic particles such as Ni has been shown to significantly enhance fracture toughness, although it often degrades optical transparency. In this work, Ni nanoparticles were selectively introduced into a near‐surface region of borosilicate glass using a hierarchical nanoporous layer as a template. Ni nanoparticles with an average diameter of about 27 nm were distributed as isolated particles within a near‐surface layer approximately 1.5 µm thick. Although coloration occurred after nanoparticle precipitation, the glass retained visible transparency, in contrast to previously reported bulk‐dispersed metal nanoparticle systems. After formation of the metallic nanoparticle layer, mechanical testing showed a 2.1‐fold increase in crack initiation resistance and a 1.5‐fold increase in fracture toughness. Birefringence analysis indicated that this improvement was not associated with a significant increase in residual compressive stress. Taken together, these observations suggest that surface‐localized dispersion of ductile metal nanoparticles can improve the damage resistance of transparent glass without altering the bulk composition.