Segregation in bimetallic alloys and its influence on wetting on a positive temperature coefficient resistor BaTiO3 ceramic

Bimetallic alloys have been considered in terms of their wetting behavior o n semiconducting BaTiO3. In an earlier study, wetting behavior was strongly linked to ohmic contact behavior. However, the wetting behavior does not a lways correlate in the form of high work of adhesion-low contact resistance . The departure from this trend is associated with the nature of the segreg ation of the solute. Two extreme cases are considered in this study: no dri ving force for segregation and a strong driving force. These cases are char acterized with sessile drop experiments and qualitatively analyzed in terms of thermodynamic analysis, both a surface enrichment model is considered t ogether with an energy diagram approach. Both models give excellent qualita tive agreement to the observed wetting behavior of the bimetallic alloy-BaT iO3 system. (C) 2001 American Institute of Physics.