CONTINUOUS MICROSCRATCH MEASUREMENTS OF THE PRACTICAL AND TRUE WORKS OF ADHESION FOR METAL CERAMIC SYSTEMS/

Using a continuous microscratch technique, the adhesion strengths of P t, Cr, Ti, and Ta2N metallizations to NiO and Al2O3 substrates have be en characterized. The practical work of adhesion was determined as a f unction of both thickness and annealing conditions. For all except the Ta2N films, the practical work of adhesion increases nonlinearly from a few tenths of a J/m(2) to several J/m(2) as the thickness of the th in film is increased, indicating that a greater amount of plastic work is expended in delaminating thicker films. Further, the practical wor k of adhesion also increases with increasing annealing temperature, in dicating stronger bonding at the interface. In the limit that the film thickness tends to zero, the plastic energy dissipation in the film t ends to zero. As a result, the extrapolation to zero thickness yields the true work of adhesion for that system.