Aluminum alloy/alumina-based ceramic interactions

Wetting experiments were performed on eutectic ZrO2/Al2O3 (ZA), ZrO2/Al2O3/TiO2 (ZAT), and ZrO2/Al2O3/SiO2 (ZAS) ceramic substrates with different Al alloys. Four major variables were tested to study the wetting behavior of the different ceramic-metal systems. Variables include holding time, melt temperature, alloy, and ceramic compositions. An experimental setup was designed to measure in situ contact angles using the sessile drop method. For any ceramic substrate, a temperature over 950 °C was necessary to observe an equilibrium wetting angle of less than 90 ° with pure Al; by alloying the aluminum, wetting could be observed at lower temperatures (θ = 76–86 ° at 900 °C for Al-10 wt.% Si, θ ~72 ° at 850 °C for Al-2.4 wt.% Mg) forming clean interfaces. Finally, ZAS specimens reacted with molten Al alloys over 900 °C to produce Zr-Al based intermetallics at the metal-ceramic interface.