Fracture toughness enhancement via sub‐micro silver‐precipitation in silica glass fabricated by spark plasma sintering

Abstract Sub‐micro silver (Ag) precipitated in silica (SiO 2 ) glass was prepared via spark plasma sintering (SPS), and the microstructure, mechanical properties, and thermal conductivity were investigated. The in situ formation of Ag sub‐micro particles through decomposition of silver nitrate (AgNO 3 ) was homogeneously distributed within the SiO 2 matrix. By precipitation of Ag particles, larger steady‐state creep deformation and plastic deformation were observed owing to the ductility of the Ag particles. Moreover, crack bridging and pull‐out of Ag particles were observed during crack propagation. As a result, the fracture toughness of SiO 2 glass improved with increasing Ag content. The sample with 1.4 vol% Ag sintered at 1200°C showed the highest toughness value of 2.15 ± 0.2 MPa m 1/2 . Larger Ag particles in the samples sintered at higher temperatures tend to deform easily, resulting in larger ductility. In addition, incorporation of Ag particles improved thermal conductivity.