Abstract

This paper demonstrates a comparative study of a relatively novel fibre laser and a conventional CO 2 laser to surface-process silicon nitride (Si 3N 4) engineering ceramic. The objective of the research is to investigate the threshold of the novel fibre laser and compare it to the conventionally used CO 2 laser to process Si 3N 4 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 Si 3N 4 engineering ceramic differed to that of the CO 2 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 Si 3N 4 engineering ceramic. The CO 2 laser wavelength when surface treating the Si 3N 4 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 Si 3N 4 engineering ceramic. © 2011 Springer-Verlag London Limited.