Joining of C/C composites by using B4C reinforced phosphate adhesive

A B4C reinforced phosphate adhesive for bonding C/C composites was developed. The mechanical properties were tested at room temperature after bonded specimens were treated at different temperatures from room temperature to 1500 °C. The results showed that the addition of B4C could greatly improve 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 decreased gradually from 7.9 MPa at RT to 3.3 MPa at 900 °C; then it increased up to 4.1 MPa at 1300 °C; however, when the temperature was over 1300 °C, the value decreased again but still remained above 2 MPa.