The wetting of (La0.6Sr0.4)(Co0.2Fe0.8)O3-delta substrates by Ag-CuO was investigated using the standard sessile drop technique, followed by metallographic examination of the quenched specimens. The addition of CuO substantially improves the wetting of these substrates by silver. The largest improvements in contact angle are observed at low CuO-content, apparently through the formation of a homogeneous silver-copper oxide liquid at the area of sessile drop/substrate contact. At a critical composition of x(CuO) similar to 8 mol% the mechanism of wetting changes, undergoing a transition initiated by the formation of two immiscible liquids within the molten sessile drop. (C) 2005 Springer Science + Business Media, Inc.