B4C改性酚醛树脂粘接SiC陶瓷的高温性能

以酚醛树脂为基体，B₄C为改性填料制备出高温粘结剂，并对 SiC陶瓷进行粘接。对粘接样品热处理之后测试各试样的室温剪切强度。结果表明，700 ～800℃ 热处理后，胶层剪切强度超过 20 MPa。利用扫描电镜以及能谱仪研究粘接试样的断面形貌及其结构特征 , 并借助裂解色谱/质谱联用仪研究了酚醛树脂及B₄C改性酚醛树脂 750℃ 裂解的主要挥发分。研究表明，B₄C与CO等挥发分之间的改性反应可以有效地改善粘结胶层高温下的结构致密性、稳定性。反应产物B ₂O ₃高温熔融，具有良好的润湿/粘附性，可在一定程度上愈合、修补树脂热解产生的收缩缺陷；B₂O₃与树脂基体活性部位形成化学键合，提高了树脂基体的高温稳定性和结合强度，从而实现高温下的良好粘接。

High-temperature performance of boron carbide modified phenol-formaldehyde resin bond to silicon carbide ceramic

A high temperature adhesive was prepared using phenol -formaldehyde resin ( PF) as the matrix and boron carbide (B4C) particles as the modifier，with which silicon carbide ( SiC) ceramics were bonded. The mechanical property of the adhesive was tested at room temperature af ter being heat-treated in the temperature range from 300℃ to 800℃respectively. The result s indicate that an out standing shearing st rength over 20 MPa could be achieved for SiC ceramics after treatment at 700～800℃. The micro-morphologies at bonding interfaces were investigated by SEM and EDAX，and the main volatiles originating f rom pyrolysis were investigated by pyrolysis gas chromatography-mass spectroscopy. A compact and stable st ructure can be achieved through the modifying reaction between B4C and volatiles such as CO. The reaction product B2O3 being melt at high temperature possesses satisfactory wet tability and adhesive capacity，which can close and mend the shrinkage lacunas. B2O3 also combines with active groups in the resin matrix，which can be responsible for the improvement of the bonding cement stability and adhesive st rength at high temperature.