The metallization of AlN ceramics fabricated via direct hot-pressing micro-Ag particles in air

AlN metallization substrates hold broad application potential in the field of electronic packaging due to their high thermal conductivity and unique electrical insulation properties. The present work reports a method for preparing Ag coatings by directly pressing and sintering micro-Ag particles on the AlN surface in air without additional brazing fillers or pre-treatment. The in-situ formation of the Ag-containing Al₂O₃ interlayer (∼200 nm) is critical for the interfacial bonding at the AlN/Ag interface. The diffusion of Ag particles into Al₂O₃ not only enhances the interfacial adhesion of the Ag layer but also improves thermal conductivity. Notably, AlN/Ag exhibits a high bonding strength of 67.6 MPa with an excellent thermal conductivity of 178.7 W·m⁻¹·K⁻¹ at 950°C. The Ag layer demonstrates superior surface hardness and electrical conductivity at 900°C due to its high density and low grain boundary density.