Adhesion of ceramics to Inconel 600 under various chemical conditions

Abstract

AbstractTwo types of catalytic ceramic coating for steam reforming were adhered to the surface of an Ni‐based alloy, Inconel 600, by sintering at high temperatures (1000°C) in atmospheric air. The interfaces were subsequently investiagated with AES, SAM and depth profiling after being submitted to a direct‐pull test to obtain a measure of the adhesion strength. It was found that the adhesion of the Mg‐rich coating was caused mainly by diffusion of Mg from the ceramic into the Cr2O3 scale of the metal substrate. After reduction in H2 (activation of the Ni catalyst), a substantial drop in the adhesion strength was found. This was caused by metallization of Ni‐rich islands in the interface zone formed on the metal during sintering. These findings suggest that firing temperature with lower oxygen partial pressure (during sintering) will lead to a more stable adhesion strength. The other, Al‐rich coating had a much weaker adhesion strength compared to the Mg‐rich coating.