A Comparative Study on the Processing Parameters during Fibre and CO2 laser Surface Treatments of Silicon Nitride Engineering Ceramic

This paper demonstrates a comparative study of a relatively novel fibre laser and a conventional CO2 laser to surface-process silicon nitride (Si3N4) engineering ceramic. The objective of the research is to investigate the threshold of the novel fibre laser and compare it to the conventionally used CO2 laser to process Si3N4 engineering ceramic and to produce a laser surface treatment free from major surface cracking without using any of the pre- or post heating techniques as this would increase the cost of the process and add more expense to the product when considering a bigger view point. The results showed that the fibre laser surface processing of the Si3N4 engineering ceramic differed to that of the CO2 laser as the Gaussian beam modes, the beam quality factors, wavelength and the beam delivery systems were different between the two lasers. This consequently had a different effect on the surface of the Si3N4 engineering ceramic. The CO2 laser wavelength when surface treating the Si3N4 engineering ceramic was being absorbed more than that of the fibre laser as higher power density and same traverse speed was used to reach the threshold for the Si3N4 engineering ceramic.