Electronic Material Properties - und Geowissenschaften ...

Relative density
1.00
0.95
0.90
0.85
0.80
0.75
0.70
1300°C
1150°C
Film exp. Film model
Bulk
0.65
0 2000 4000 6000 8000 10000
Isothermal time [s]
Fig 1. Experiment and modelled densification curves for 2 sintering temperatures
The effect of film thickness was also investigated. Thinner layers seem to be more
constrained, as they densify more slowly than thicker ones. Particle rearrangement may be
hindered close to the substrate, which leads to a lower local density than elsewhere in the
film (Fig 2).
Fig. 2 Polished cross-section of a sintered film
Finally, an extension of the sintering model to anisotropic bodies has been proposed. In
the case of transverse isotropy, 2 free sintering strain rates, 2 uniaxial viscosity as well as
3 viscous Poisson’s ratios are introduced. In specific cases, such as constrained sintering,
only 2 Poisson’s ratios are required. The experimental determination of these parameters
is still challenging, as anisotropic specimens have to be obtained before being loaded in
different directions and their strains measured.
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