Copper tracks processing on alumina by laser cladding: Elaboration and characterization

A laser process allows achieving in air electrical tracks on alumina substrates with an electrical conductivity of 5.106 S m−1. Copper paste was first put on alumina substrates and it was heated following a narrow track (c.a. 400 μm wide). Copper melted and oxidized partially during treatment forming cuprite Cu2O. A reaction occurs between Cu2O and alumina substrates which provides, after cooling, a good bonding of the copper-based tracks onto the substrates. Conditions of laser exposure have to be sharply controlled: if insufficient, tracks do not adhere to the substrate, and if too long, alumina substrates are hollowed, cracked, with vaporizations of copper and ejections of alumina. However the feasibility of such a process is now established.