Si3N4, AlN and SiC ceramics with a relative density of 96.5% or more were processed by YAG laser cutting, and the change in strength due to the processing was evaluated.
When a single laser beam was irradiated, the beam depth ? increased in proportion to the energy E [J] of the laser beam. The relationship between E and ? is about 1J→0.6~0.8mm, 2J→0.9~1.1mm. The beam-hole diameter with conical shape was 0.15 to 0.22 mm at the irradiated surface. The Vickers hardness of the processed surface decreased to about 13-22%. The 3-point bending strength decreased to 33-45%. The surface roughness decreased greatly from 1/62 to 1/146. From the observation of the structure of the irradiated cross section, the structure melted by heat of laser beam was observed in Si3N4 and AlN, and the sintered structure with traces of processing was observed in SiC.departmental bulletin pape
