Cobalt doped glass for the fabrication of percolated glass-alumina functionally graded materials

The present research was focused on the development of a new glass to produce glass–alumina FGMs. The glass formulation, belonging to theCaO–ZrO2–SiO2 system, was doped with cobalt, by adding a small molar percentage (about 0.1 mol%) of CoO, in order to obtain a blue glass,which could be useful to appreciate the final compositional gradient. The glass was accurately characterized, evaluating its thermal behaviour, itsmechanical properties, and its attitude to crystallize during a thermal treatment. Subsequently, the glass was used to produce glass–alumina FGMsvia percolation and the so obtained specimens were analysed in order to evaluate the effect of the glass infiltration. The possible development ofnew crystal phases, in particular, was tested via micro X-ray diffraction and the elastic properties gradient associated with the compositionalgradient was measured via depth-sensing Vickers microindentation.