Impairment of Strength of Quartz Glass through Wetting by Liquids

Abstract

IN a recent communication¹, Radd and Oertle attributed the impairment of the tensile strength of glass fibre fabrics to a chemical solution process. Recently I have measured the tensile strength of quartz-glass rods immersed in various liquids. The rods, which were supplied by the Amersil Quartz Division of Engelhardt Industries, Inc., were selected for a uniform diameter of 1 mm. and cut to a length of 10 cm. They were annealed to remove residual strains. Three-point bending, using a calibrated spring, was used to apply a maximum stress at the centre, where the rods were scratched before they were broken. Scratches of identical depth were made on the underside of each rod by cutting with a diamond cutting tool that was applied with a constant force. All experiments were performed in a moisture-free atmosphere on previously dried rods. The mean loads at fracture, together with the 95 per cent confidence interval for the liquids water, oleylamine, and n-hexadecane, are shown in Table 1. Great care was taken to free the n-hexadecane of all polar impurities and the oleylamine of water. The last column shows the probability of the null hypothesis M ₁ – M ₂ = 0 being correct for the means of the two pairs water–oleylamine and oleylamine–n-hexadecane, respectively².