Joining of surface modified carbon/carbon composites and LAS glass ceramic

Carbon/carbon (C/C) composites modified with SiC-MoSi₂ coating are joined to Li₂CO₃ -Al₂O₃-SiO₂ (LAS) glass ceramic using MgO-Al₂O₃-SiO₂ (MAS) glass. The effects of joining temperature, joining pressure, and holding time on the shear strength of the sample are studied. The optimal technological parameters obtained by orthogonal experiments are 1200°C, 20 MPa, and 15 min. Under these conditions, the shear strength of the joined sample is up to 30 MPa. The microstructure of the interfaces is analyzed by scanning electron microscope (SEM), energy disperse spectroscopy (EDS), and backscattered electron image (BEI). Results show that Si and C elements distribute in a gradient in the interface, while an interlayer about of 15 μm is produced which accelerates the joining of SiC-MoSi₂ coating and C/C composite. Moreover, C/C(SiC-MoSi₂)/MAS/LAS interfaces are formed due to the interdiffusion that occurrs at the interfaces between the glass and SiC-MoSi₂ coating and LAS glass ceramic, which contributes to the superior joining of interfaces.