Strengthening of glass by hybrid organic-inorganic coatings

The effect of a hybrid organic-inorganic coating on the strength of window glass plates was investigated using ball-on-ring (BOR) and ring-on-ring (ROR) failure tests. Firstly, the reproducibility of the failure tests performed on non-coated glass plates was measured. The strength data obtained for the BOR and ROR tests were about 420 MPa and 130 MPa, respectively. Secondly, effects on glass plate strength of an applied coating, dust level in the coating, coating curing conditions (temperature and time), and aging time of the coating were studied. Reproducible coating layer thicknesses (2.25 mu m +/- 1.5%) were obtained. Moreover, the applied coating increased the strength of the glass plates. In contrast, changing the coating processing conditions did not affect the strength of the coated glass plates. Depending on the type of bending test and the batch evaluated, the applied coating yielded an increase of similar to 6 to 90% of the strength of the uncoated glass plates, the Weibull modulus notably remained approximately the same. Furthermore, no effect on strength of the dust level in the coating was observed. In addition, the coating layer thickness did not affect the strength, while only a minor decrease in strength due to aging of the coating was observed. (C) 1998 Elsevier Science B.V. All rights reserved.