Joining of silicon carbide by a heat-resistant phosphate adhesive

Abstract

In this paper, SiC was bonded with a phosphate inorganic adhesive prepared from H₃PO₄ and Al(OH)₃ as the matrix and Si and B₄C as the inorganic fillers. The properties of the obtained adhesive were analyzed by XRD, TG-DSC, IR, shear strength tests and SEM. The results showed that the phosphate adhesive exhibited outstanding heat-resistant properties and excellent bonding strength. The addition of B₄C could greatly improve the adhesive's mechanical properties due to the formation of borosilicate glass and the volume compensation came from B₄C's oxidation. The shear strength of bonded specimens could be up to about 10 MPa after heat treatment at 1300 °C, attributed to the generation of mullite and borosilicate as well as the reasonable compensation for the adhesive's volume.