Infiltration of glass flaws by alkoxide coatings

Controlled flaws were produced in silica glass by Vickers indentations. The flaws were examined after formation, after coating with a tetraethoxysilane (TEOS) solution, and after removal of the coating using Ar + ion sputtering. Flaws with widths less than 35 nm were healed by the solutions, while wider flaws were unaffected by the coatings. For the healed regions, the solutions infiltrated into the flaw to a depth of at least 70 nm. A model of the strengthening of glass due to filling-in and healing by sol-gel coatings is modified to take into account the effect of flaw width on infiltration.