EXCIMER-LASER INDUCED MELTING AND DECOMPOSITION OF TECHNICAL CERAMIC SURFACES AND THEIR PROPERTIES

The chemical, structural and topographical changes after the irradiati on of technical oxide (Al2O3, ZrO2) and nonoxide ceramics (SiC, Si3N4) with a XeCl-Excimer Laser were studied as function of the applied ene rgy density and number of pulses. The silicon-based nonoxide ceramics decomposed during a temperature and pressure induced process and an ad herent up to 1,5 mu m thick crystalline Si-layer remained on top of th e specimen surface. In contrast, the oxide ceramics underwent a meltin g and rapid resolidification process without a chemical alteration. Th e minimization of surface defects on Al2O3 was used to generate a two- fold increase in Weibull's modulus m compared with untreated samples, whereas the silicon layer on top of SiC was helpful to generate and im prove metal-ceramic joints between SiSiC and AlMgSil.