Examination of temperature distribution and the thermal effects on Si3N4 engineering ceramics during fibre laser surface treatment

The thermal effects of fibre laser surface treatment on a Si3N4 engineering ceramic were studied using a computational finite element analysis (FEA). Temperature increases on the surface of the Si3N4 during fibre laser processing were measured using an infra-red thermometer; temperature distributions in the bulk were measured with specifically located thermocouples. A computational model by using FEA was then developed to model the flow and the distribution of the radiated heat resulting from the fibre laser treatment of the Si3N4 ceramic. By utilising data obtained from a TG-DSC analysis the FEA model predictions of the temperature distribution were used to map phase transformations and significant events occurring during the fibre laser surface treatment of the Si3N4. The TG-DSC analysis also indicated that the fibre laser surface treatment generally resulted in a phase transformation of the Si3N4 from α-phase to β-phase modification as elongated rod-like grains were found.

Research highlights
► Fibre laser surface treatment process of Si3N4 engineering ceramic was examined.
► An experimental model was verified with a computational finite element model.
► Phase transformation was then elucidated during fibre laser processing of the Si3N4.
► Extended parameters for fibre laser processing of the Si3N4 were also found.