Influences of Additives on the Adhesion of Graphite at High Temperatures

Chinese Academic of Sciences, Taiyuan 030001, China)Based on the high temperature adhesive (HTA) composed of phenol-formaldehyde resin(PF) and boron carbide (B4C) ceramic powders, new high temperature adhesives (HTAs) were prepared by using secondary additives, aluminium oxide (Al2O3) or silicon (Si) or fumed silica (SiO2) as additives to modify the properties of the adhesives. Graphite components bonded by the above adhesives were heat-treated at different temperatures ranged from 200℃ to 1500℃. Subsequently their adhesive shear strengths were tested at room temperature. Results show that the additives have an obvious influence on the adhesion properties of bonded graphite components. In additional, fumed silica has a great effect on improving the adhesion property of HTA, and the adhesive consisting of phenol-formaldehyde resin, boron carbide and fumed silica has satisfied adhesive strength.