MECHANICAL STRENGTH OF CHEMICALLY STRENGTHENED GLASS SUBSTRATE FOR DISK DRIVE

Abstract

  Mechanical strength of the glass substrate after chemically strengthening exhibits three modes in Weibull chart according to the distribution of internal stress embedded in the substrate surface by ion-exchange. By chemically strengthening, average fracture strength of glass substrate increases from σ =96.3MPa to σ=300-650MPa depending upon the depth of ion-exchange. Fracture probability, however fracturates from 5E10^-13 to 1.5E10^-38, which crosses over the fracture probability of the raw-glass (F=2.1E10^-23). This paper discusses the theoritical assumption on three-mode model appeared in the Weibull chart in conjunction with experimental data.