Laser-induced metallization of porous Si₃N₄ ceramic and its brazing to TiAl alloy

The poor wettability of traditional brazing filler alloys on the surface of ceramics always lead to the formation of defects in the joints and weaken the bonding strength eventually, especially the porous ceramics. Metallization on ceramics is an effective way to improve the wettability. In this work, laser-induced cladding process was applied to metalize the surface of porous Si₃N₄ ceramic, and the traditional AgCu eutectic filler alloy can wet on the metalized surface completely. The metalized porous Si₃N₄ ceramic brazed to TiAl alloy successfully using AgCu filler alloy. The interfacial microstructure and mechanical property of the porous Si₃N₄/TiAl alloy brazed joint was significantly improved by the novel laser-induced metallization process.