Scratching of thin coatings on hard substrates is studied experimentally and
numerically, in the latter case by use of the finite element method. In particular the
delamination behaviour at scratching, by increasing the normal load up to failure, is
of interest. The adhesion of the coating to the substrate is modelled as a cohesive
zone where relevant model parameters are determined experimentally using the
double cantilever beam test with uneven bending moments (DCB-UBM).
Good correlation between experimental and numerical results were achieved
and the most important finding confirms the fact that the delamination
behaviour was very much dependent on the critical energy release rate of the
film/substrate interface. The results achieved are directly relevant for thin
film polymer coatings but can also be applied in more general situations
as a comprehensive parameter study is performed using the finite element
method.
Keywords
scratching, finite element analysis, contact, delamination,
cohesive zone, adhesion, thin film
