Effect of Silicone Quenching and Acid Polishing on the Strength of Glass

Soda-lime glass rods 5 mm in diameter were quenched in silicone oil and also in a saturated hydrocarbon oil of similar viscosity. The effect of etching, etching and quenching, and etching, quenching, and re-etching was examined in relation to the strength of the rods. Rods quenched in the silicone oil were no stronger than those quenched in the hydrocarbon oil. Etched rods had a strength of 300,000 psi. Quenching these high-strength rods reduced their strength to 110,000 psi. This decrease in strength may be explained in terms of the formation of crystalline and noncrystalline microflaws during the heating and cooling cycle. Re-etching, after quenching, resulted in rods with a maximum strength of 384,000 psi.