Microstructural and chemical changes at the Ni/YSZ interface

A bent nickel wire was pressed against a yttria-stabilised zirconia (YSZ) s urface, creating a small contact area. The Ni/YSZ interface was investigate d and characteristic microstructures were found to develop during 200-300 h heat treatment at 1000 degreesC in 97% H-2/3% H2O with and without polaris ation. A ridge of impurities up to 1.6 mum high was seen to develop along t he Ni/YSZ/H-2 boundary. The impurity phase can be characterised as an alkal i silicate phase containing Mn, Na, Ti, Mg, K, Al and Si. Most of these ele ments seem to be coming from impurities in the nickel. The initially flat c ontact area on the YSZ developed a hill and valley structure with an amplit ude of 100 nm. The nickel wires showed negative imprints of the YSZ structu res. (C) 2001 Elsevier Science B.V. All rights reserved.