Glass strengthening by SiO2-TiO2 organically modified silica coating

Abstract

An alcohol based and water based coating solutions containing SiO2-TiO2 were prepared using sol-gel method. Vickers indented soda-lime-silica float glass samples were coated by applying dip-coating technique and their strengths were determined using Ring-on-Ring test method. Weibull statistics were utilized to examine and interpret the strength results. Clear and transparent coatings on the glasses were obtained. Scanning Electron Microscopy examination revealed that the coatings (alcohol and water based) had a thickness of about 2 gm and partially filled surface cracks. The increase in glass strength of about 170% was obtained with both coating systems. Vickers hardness values of the glasses coated with alcohol based and water based coatings were determined as 3.6 and 4.8 GPa, respectively. In addition, scratch tests performed on the coated glasses indicated that there was a good bonding between the glass samples and the coatings. Fourier Transform Infrared Spectra clearly revealed that the organic groups, Si-O-Ti and Si-O-Si bonds form in the gels heat-treated at 200 degrees C. (c) 2006 Elsevier B.V. All rights reserved.