Abstract
The prediction of hardness is possible for crystalline materials, but not possible for glasses so far. In the present paper, we describe and discuss several important factors that should be used for predicting the hardness of glasses. To do so, we have studied the influences of thermal history and chemical composition on hardness of silicate glasses. By subjecting E-glasses of different compositions to various degrees of annealing, it is found that hardness decreases with the fictive temperature. Addition of Na 2O to a SiO 2–Al 2O 3–Na 2O glass system causes a decrease in hardness. However, the number of non-bridging oxygen per tetrahedron (NBO/T) is not the only parameter determining hardness. In addition, it is found that the effect of ionic radius on hardness is opposite for alkali and alkaline earth ions. Hence, changes of the structural network occurring at the atomic scale must be taken into account when predicting the effect of composition on hardness. The principles used in the calculation of hardness of crystalline materials are only partly valid for glasses.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
