Microstructures of laser bonded SiC ceramics with Zr interlayers

Abstract SiC plates were bonded using a laser beam scanning method. As an interlayer material, a Zr sheet 0.4 mm in thickness was used. Joining was performed at room temperature in air under atmospheric pressure. The interfacial microstructures along with their atomic compositions of the Zr/SiC reaction zone were analyzed. In the Zr side, diffused Si formed ZrSi 2 , Zr 5 Si 3 C x , and Zr 4 Si phases. Carbide transformation was observed (Zr + C → ZrC x ) near the Zr/SiC interface. No crystallographic orientation relationship was found in most of the grains; however, a boundary of ZrSi 2 [1 0 0] parallel to Zr 5 Si 3 C x [ 0 1 1 ¯ 1 ] was found in the observation. In the SiC side, penetrated Zr was found at up to 120 μm from the Zr/SiC interface. The diffused Zr formed a silicon-rich metastable phase of ZrSi y ( y > 3.3).