石墨/氧化铝陶瓷的粘接连接

BONDING OF GRAPHITE/ALUMINA CERAMICS BY ADHESIVE

以酚醛树脂和B4 C为原料制备高温粘结剂 ,并对石墨 /陶瓷 (Al2 O3)进行粘接连接。对不同温度热处理后的石墨 /陶瓷粘接样品进行剪切强度测试。结果表明 ,高温粘结剂对石墨 /陶瓷材料具有良好的粘接性能。在 60 0 ,80 0℃热处理后的粘接样品由于胶层中树脂炭骨架的破坏而粘接强度不够理想 ,但在 10 0 0℃以上的热处理后 ,石墨 /陶瓷接头具有较高的连接强度和抗热震性能。在经历多次的热冲击后 ,粘接强度先降低 ,而后趋于稳定 ,并呈现出一定程度的回升。利用扫描电镜 (SEM )对粘接界面的观察发现 ,在 10 0 0℃以上的热处理后 ,接头破坏形式是混合破坏 。

A high temperature adhesive was prepared using phenol-formaldehyde resin as matrix and boron carbide (B 4C) as additives to modify the properties of the adhesive. Graphite/ceramics (Al 2O 3) was bonded by the adhesive and treated at different temperatures. The bonding shear strength was tested at room temperature. Results show that the adhesive strengths of the joints treated at 600 ℃ and 800 ℃ are not satisfactory due to the break of the cement framework during the heat_treatment. But good bonding strength and thermal shock resistance are achieved when the treatment temperature is higher than 1 000 ℃. The adhesive strength decreases at beginning and then stabilizes or back_jumps to some extent after several times for thermal shock. The micrograph of the bonding interfaces was studied by means of SEM. It is indicated that the failure mode of the joints is mixed failure. The broken ceramics matrix can be founded on the bonding interface.