Foamy coating obtained by laser ablation of glass ceramic substrates at high temperature

This paper presents a study of the effect of temperature in the machining of glass ceramic cooking plates by laser ablation. A Q-switched Nd:YAG laser at its fundamental wavelength of 1064 nm with pulsewidths in the nanosecond range was used. The beam was focalized and scanned over the surface covering an area of several squared millimetres. With the same irradiance and process parameters the rise of the surface temperature some hundreds of degrees changes drastically the ablation conditions. As temperature is risen the amount of particles ejected from the interaction zone diminishes, recasting over the processed area generating a white and foamy self-layer. The size of the ejected particles and the morphology, composition and microstructure of the new layer is described. This layer could be used to change the thermal conductivity of the glass ceramic plate as well as for aesthetic purposes.