Active metal brazing of Si3N4 to metals

Ceramic-metal bonds require high strength at elevated temperature for a number of technical applications. The results presented in this work demonstrate the effect of active metal bonding temperature and metal foil on the apparent peel bond strength between Si3N4 and Cu or Ni (in some cases using Mo as an interlayer). Incusil ABA(TM) and Cusil ABA(TM) have been used as the active metal braze alloys. For the system Si3N4/Incusil ABA(TM)/Mo foil/Incusil ABA(TM)/Ni foil, the highest average peel strength (140 N/cm) was obtained at a bonding temperature of 720 degrees C. The highest strength values were obtained without a Mo foil interlayer, as for example the system Si3N4/Incusil ABA(TM)/Cu foil. The highest peel strength (595 N/cm) were obtained after brazing at 722 degrees C for 20 min. Under this condition the Cu foil sheared. This suggests that the actual bond strength is considerably higher than the 595 N/cm value determined. Complementary experiments with different thicknesses of metal foil showed that in the system Si3N4/Incusil ABA(TM)/Mo foil/Incusil ABA(TM)/Ni foil no significant difference were obtained by using different foil thicknesses. When applying Cu foil, it appears to be advisable to use a thicker foil. A few investigations were performed by replacing Incusil ABA(TM) With Cusil ABA(TM). NO increase of strength was found when applying Cusil ABA(TM) as compared to the experiments using Incusil ABA(TM).