Epoxy layers are useful as protection coatings
for metals. Of course, the adhesion of coatings must be strong and
durable. It is the morphology and composition of the interface between
the coating and the metal that determines the strength of the adhesion.
For studies of the conditions of interfaces, transmission electron
microscopy is the technique of choice.
An epoxy coating was applied (by Jeroen van den Brand from
NIMR) onto an aluminium substrate after the growth of a pseudoboehmite
surface layer. The FIB was then used to cut a cross section lamella
across this delicate interface (figure 1). On the TEM picture (figure
2) the interface layer with numerous needles, that are embedded in the
coating, is clearly resolved.
Figure 1
Figure 2
This study showed that the large contact area of
the massive amount of needles is responsible for the strong adhesion of
the epoxy layer onto the aluminium substrate.
Last updated by Paul Alkemade on
11 March 2004