Distribution of temperature during fibre laser radiation and effects thereon phase transformation of ZrO 2 engineering ceramic

Distribution of surface and the bulk temperature was recorded during fibre laser surface treatment of ZrO₂ engineering ceramic. The experimental readings were then compared with a finite element model which showed the flow and distribution of the laser induced heat as a result of the fibre laser surface treatment. Moreover, thermogravimetry–differential scanning calorimetry was used to collect data with respect to physical changes during heating and cooling of the ZrO₂ engineering ceramic. The thermogravimetry–differential scanning calorimetry data and the finite element model predictions were then used to map the phase transitions within the ZrO₂ engineering ceramic resulting from fibre laser surface treatment. The mapping revealed that the fibre laser surface treatment had generally resulted in a phase transformation of the ZrO₂ engineering ceramic from the monoclinic (M) state to a mixture of tetragonal and cubic (T+C) followed by partially formed liquid (L) phase during fibre laser surface treatment and from L to T+C then T, followed by the M state during solidification.