Since the final decades of the last century, through the pioneering work of Temple and collaborators, the possibility and effects of surface heat treatments on glass by means of laser heating have been demonstrated. However, the minimum parameters required for these processes, especially on the surfaces of oxide glasses, remains a subject of research since the dependence of these parameters on the nature of the glass to be processed still unknown. In this research project, we are proposing to study the influence of the glass forming ability (GFA) on the laser surface processing variables, especially on the minimum scanning speed of the laser. For this purpose, glasses with different GFA will be used for surface heat treatment experiments, under CO2 laser radiation, with different scanning speeds. It is intended, therefore, to correlate the minimum scanning speed (before the start of crystallization) with the GFA of the glass to be processed. Glass based on silica and boron will be prepared by the conventional melting and solidification process using the Splat Cooling technique. After heat treatment the glasses in resistive ovens, in order to minimize the thermo-mechanical stresses, samples will be cut and polished optically in the dimensions 2x2 cm. By means of a high-powered CO2 laser, coupled to a two-dimensional galvanometric scanning system, lines will be produced on the surface of the samples with different scanning speeds. The lines will be characterized in terms of their crystallinity by means of X-ray diffraction (with a micro-area accessory). Thus, it is expected to obtain a correlation between the minimum possible speed for heat treatment on the surface of oxide glasses with the respective GFA.
News published in Agência FAPESP Newsletter about the scholarship: