THE FRACTURE ENERGY OF INTERFACES - AN ELASTIC INDENTATION TECHNIQUE

Debonding of thin refractory coatings between two oxides has been investigated by developing a new, simple indentation test technique. The method is based on a Hertzian indentation approach, modified to incorporate crack propagation down an interface plane beneath and parallel to the indented surface. The test method has been analyzed using finite elements and the results validated by experiments on homogeneous solids. Test materials have been selected to distinguish coatings capable of debonding from those immune from debonding. The implications for fiber coatings suitable for use in high temperature oxide based composites have been discussed.