DESIGN, ASSEMBLY AND CHARACTERIZATION OF COMPOSITE ...

6.1. Introduction
CHAPTER 6 BARIUM TITANATE NICKEL COMPOSITES
BY LIQUID PHASE SINTERING
As shown in chapter 5, Robocasting promises fabrication of ceramic-metal
composites for novel applications. Co-printing strategies include real-time mixing of
colloidal inks for graded structures and serial printing for abrupt material transitions.
However, major challenges in the ensuing densification process result from mismatches
in sintering kinetics and thermal expansion coefficient between the ceramic and metal
components. These difficulties often lead to distorted or cracked structures and failure of
the printed structure as a functional device. The efforts described in chapter 5 seek to
achieve co-sintering by significant inclusion of refractory BT particles in the Ni phase.
This approach met with limited success at a volume fraction of BT around 80%. While
this solution preserves the pure BT properties in the ceramic phase and the Ni and BT
mixture is conductive for electrical applications, this solution is wholly inadequate if one
desires mechanical ductility from the metallic phase. Clearly an alternative approach is in
order.
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