2 research outputs found
Rheological Behavior and Slip Casting of Al2O3–Ni Aqueo Suspensionsus
A strong effort has been devoted recently toward processing of
metal–ceramic composites with tailored microstructure by colloidal
methods. The aim of this work is to optimize the rheological
behavior of concentrated Al2O3–nickel (Ni) aqueous
suspensions and further slip casting in order to obtain dense
green composites. Compositions with Ni relative contents ranging
from 5 to 75 vol% were prepared from suspensions with high
solids loadings (50 vol%) by adjusting the colloidal stability of
each component in terms of pH, mobility, dissolution conditions,
and influence of polyelectrolytes. The rheological properties
were measured under controlled rate and controlled stress conditions
at different basic pH conditions and contents of polyelectrolyte.
Better rheological conditions of the mixtures were
found for pH 10 and 1.0 wt% polyelectrolyte. Minimum viscosity
was obtained for suspensions containing 15 vol% of Ni.
The analysis of flow curves demonstrates that the suspensions
form a structure at very low shear, hindering sedimentation.
Homogeneous slip cast bodies with green densities up to 70%of
theoretical and up to 75 vol% Ni were sintered in Ar to achieve
dense biphasic composites.Peer reviewe