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Reduction and Sintering of a Nickel–Dispersed‐Alumina Composite and Its Properties
Author(s) -
Sekino Tohru,
Nakajima Toshio,
Ueda Satoru,
Niihara Koichi
Publication year - 1997
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.1151-2916.1997.tb02956.x
Subject(s) - materials science , nickel , non blocking i/o , sintering , composite number , dispersion (optics) , nanocomposite , composite material , metallurgy , coercivity , intergranular corrosion , microstructure , chemistry , catalysis , biochemistry , physics , optics , condensed matter physics
High‐density nickel–dispersed‐alumina (Al 2 O 3 /nickel) composites with superior mechanical properties were obtained by the hydrogen reduction and the hot pressing of alumina–nickel oxide (Al 2 O 3 /NiO) mixed powders. The mixtures were prepared by using NiO or nickel nitrate (Ni(NO 3 ) 2 · n H 2 O) as a dispersion source of nickel metal. Microstructural investigations of the composite fabricated using nitrate powder revealed that fine nickel particles, } 100 nm in diameter, dispersed homogeneously at the matrix grain boundaries, forming the intergranular nanocomposite. High strength (.1 GPa) and high‐temperature hardness were registered for the composite that contained a small amount of nickel dispersion. The ferromagnetic properties of nickel, such as high coercive force, were observed, because of the fine magnetic dispersions, which indicates a functional value of structural composites.