Effect of the surface force on subcritical crack growth in glass

The effect of the surface force on subcritical crack growth in glass was investigated in various aqueous solutions. Microcracks were induced on the glass surface by indentation method, which enabled to determine the fatigue limit, K-scc, with good precision. K-scc values obtained in solutions containing K+ or Na+ ions showed that a different factor other than the surface force 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 growth. 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 intensity factor > 0.25 MPa.m(1/2).