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Rheological and Structural Characterization of Ni–SiO 2 Nanocomposites Produced by Aqueous Colloidal Processing
Author(s) -
Vieira Luiz E.,
Rodrigues Neto João B.,
Klein Aloísio N.,
Moreno Rodrigo,
Hotza Dachamir
Publication year - 2011
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.1551-2916.2011.04754.x
Subject(s) - dispersant , materials science , nanocomposite , colloidal silica , rheology , microstructure , tetramethylammonium hydroxide , aqueous solution , chemical engineering , composite material , slurry , zeta potential , dispersion (optics) , nanoparticle , chemistry , nanotechnology , coating , physics , engineering , optics
In this work, nickel–silica nanocomposites were fabricated via colloidal processing. A rheological approach was used to characterize and to optimize a 30 vol% nickel aqueous suspension with up to 10 vol% SiO 2 nanoparticles. The slurries showed a plastic and shear‐thinning behavior that retards sedimentation and facilitates the shaping of compacts. Slips were cast in plaster mold using ammonium polyacrylate as dispersant and tetramethylammonium hydroxide for adjusting the pH at 10.0 ± 0.1. Green bodies were sintered at 900°C for 1 h in flowing argon/5% hydrogen atmosphere. Porous and dense materials were characterized by SEM/FE‐SEM , Archimedes’ densities, and Vicker's microhardness measurements. Composites showed homogeneous microstructure, refined grain size, good densification (15 vol% pores), and hardness up to 250 Hv.