Abstract: The finite element simulation for scratching test showed that undulant variation of shear stress, difference of shear stress at interface of film/substrate, surface tensile stress around contact region, several concentrations under high loading etc . played important roles on failure of film/substrate . The difference of shear stress between film and substrate near interface, which was calculated by the FEM simulation at critical load of scratching test, could be used as a criterion for estimating adhesive strength. Two mechanisms of failure of film/substrate system in scratching test have been suggested. The validity of the FEM simulation has been confirmed by the result of scratching test to TiN film deposited on different substrate. The critical load resulted from synthetic effect of film/substrate system performance, such as adhesion strength, load bearing capacity, cohesion strength. The limitation of estimating adhesive strength of film/substrate by critical load in scratching test further proved by results of friction and wear test in reciprocating sliding under low loading .

Key words: scratching test, adhesive strength, finite element simulation, stress distribution, critical loading

Author: Li Shu, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China

E-mail: shuli@imr.ac.cn

Tribology, Vol. 29, Issue 6, 2009, 592~599