Direct laser writing for rapid fabrication of porous carbon: Enhancing Si-C reaction bonding in silicon carbide ceramics

Reaction bonding is a preferred method for joining silicon carbide ceramics, with the formation of a porous carbon reaction layer being critical for effective Si–C bonding. In this study, a porous carbon layer was rapidly fabricated using direct laser writing and applied in the reaction bonding of silicon carbide ceramics. Optimization of laser parameters and joining temperature produced a well-defined porous reaction layer, which improved the proportion and distribution of silicon carbide in the joining layer, thereby enhancing joint strength. At a laser power of 30 W and a joining temperature of 1600 °C, the joint achieved a flexure strength of 233 ± 16 MPa. Subsequent annealing and oxidation treatments increased the strength to 306 ± 23 MPa. The bonded components also exhibited excellent high-temperature performance, maintaining a strength of 214 ± 16 MPa at 1300 °C.