Effect of the surface force on subcritical crack growth in glass

The effect of the surface force on subcritical crack growth in glass was in vestigated in various aqueous solutions. Microcracks were induced on the gl ass surface by indentation method, which enabled to determine the fatigue l imit, K-scc, with good precision. K-scc values obtained in solutions contai ning K+ or Na+ ions showed that a different factor other than the surface f orce dominates the crack growth. For solutions containing Li+ or Cs+ ions, a trend opposite to that predicted by the surface force theory was observed , which also suggests that the surface force does not affect the crack grow th. For solutions containing n-alkyl-trimethyl-ammonium ions the effect of the surface force on subcritical crack growth was almost negligible, namely in the range 0.010-0.027 MPa.m(1/2) in the region of an applied stress int ensity factor > 0.25 MPa.m(1/2).