Healing of cracks by green laser irradiation in a nanogold particles glass matrix composite

A transparent composite material consisting of a soda-lime-silicate glass matrix containing up to 0.5 %w gold nanoparticles (10 to 20 nm) was successfully obtained by coating glass grains and a subsequent sintering using a spark plasma sintering (SPS) furnace. Coating was achieved thanks to the reduction of gold(III) chloride trihydrate by sodium borohydride in an ethanol solution. The sintered composites were dense and transparent, but for the largest gold content where the sample exhibits a deep red color. When submitted to laser irradiation (532 nm, up to 100 W/cm2), the composite experiences a fast, localized and much more significant increase of its temperature in comparison with the pristine glass material. A temperature as high as 550 °C was reached, allowing the healing of surface crack.