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Evidence of Nearest‐Neighbor Ordering in Wet‐Processed Zirconia–Nickel Composites
Author(s) -
Pecharromán Carlos,
LópezEsteban Sonia,
Bartolomé José F.,
Moya José S.
Publication year - 2001
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2001.tb01030.x
Subject(s) - cermet , materials science , percolation threshold , nickel , cubic zirconia , ceramic , composite material , scanning electron microscope , percolation (cognitive psychology) , molybdenum , metallurgy , electrical resistivity and conductivity , engineering , biology , neuroscience , electrical engineering
Monolithic zirconia–nickel (ZrO 2 /Ni) cermets have been prepared by a wet‐processing method with nickel volume concentrations of 16%–40%. Microstructural analysis performed on scanning electron microscopy images has revealed evidence of a partial ordering of metallic particles inside the ceramic matrix. This ordering does not appear in mullite/molybdenum cermets. Complex impedance measurements have shown that the percolation threshold of ZrO 2 /Ni cermets appears at a filling factor ( f c ) of 0.34, exceeding the theoretical value ( f c = 0.16), as a consequence of its microstructural order. Electrical measurements display the expected increase of capacity near the percolation threshold. These results open the possibility to design new devices with the appealing electric, magnetic, and mechanical properties that are predicted by the percolation theory.