Joining of Cf-SiC composites and ZrB2-SiC based composites for ultra high temperature applications

Gas tungsten arc welding (GTAW) of Cf-SiC composites to themselves and to ZrB2-SiC based composites have been carried out with a filler material of (ZrB2-SiC-B4C-Y2O3-Al2O3) composite. The weld interfaces of joints of composites were clean and free from porosity and cracks. Penetration of filler material into voids and pores existing in the Cf-SiC composites was observed. An average shear strength of 25.7 MPa was achieved. The ZrB2-SiC based composite joined to Cf-SiC (CVD) composite was exposed for 300 s to the oxy-propane flame at 2300 °C. The joint and interfaces between the filler material and parent composites were found to be unaffected by thermal cycling and oxidation during the exposure to the oxy-propane flame.