Study On The Heat Resistant Adhesives For Bonding Metals To Ceramics

This paper aimed at developing a heat-resisted adhesive which bonds ceramic (Al₂O₃) to metal (steel) in engineering fields.Adhesion for metal and ceramic is a difficult problem in high temperature fields because of their thermal expansion coefficients. Inorganic adhesive is heat-resisted but the mechanical performance of the lap joint of ceramic and metal is poor. In organic adhesives, o-cresol novolac epoxy resin (ECN) shows prominent resistance to the heat and better adhesive strength because of more epoxy functional groups. Novolac resin shows better plastic in high temperature circumstance and polyimide (PI) shows better resistance to the heat. In this paper, ECN and novolac resin system was researched by the ways of TG ,DSC and FTIR. In order to improve the toughness and resistance to the heat further, the ECN and novolac resin system was modified by nano-SiO₂ and polyamide acid (PAA) of PMDA and ODA. And the experimental results showed that the shear strength and thermal destruction temperature of the cured compound modified by nano-SiO₂ and PAA were both improved. PAA of intrinsic viscosity with 0.43 dl/g was successfully synthesized in THF and CH3OH mixture solution. Based on ECN/novolac system and ECN/novolac system modified by PAA , two optimum formulations choosed to prepare heat-resisted adhesives with fillers of fine SiO₂ powder were used to bond metal (steel) and ceramic (Al₂O₃). After heat aging, the adhesives both showed better properties. The adhesives prepared with two optimum formulations can be choosed to be the heat-resisted adhesives for bonding ceramic (Al₂O₃) to metal (steel) in some engineering fields.