Ni-Cr合金による窒化ケイ素セラミックスと金属の固相接合

抄録

Silicon-nitride ceramics were joined to metal with an 80mass% Ni-20mass% Cr alloy sheet as an insert material. Joining was performed between 1323 and 1473K in vacuum. Microstructures and growth behavior of reaction layers and the influence of annealing after joining were investigated with a scanning electron microscope and an electron probe microanalyzer. On the joints bonded at 1323-1423K, the reaction layers including a large ammount of Ni solid solution were formed, whereas the reaction layers bonded at 1473K primarily consisted of fine chromium nitrides. Growth of reaction layers obeyed the parabolic law and rate constants (k_p) for the growth were 9.6×10^-16-2.5×10^-14m²/s at 1323-1473K. The activation energy for the growth of reaction layers (Q_kp) was 305kJ/mol. The fracture bending strength of Si₃N₄/Inconel couples showed the maximum of 590MPa at room temperature. The joints bonded at 1343 and 1473K were annealed at 1073K for 720ks in vacuum. Variations in microstructure and composition of the reaction layers of joints bonded at 1343K were observed, and the fracture bending strength showed large degradation. On the other hand, those of joints bonded at 1473K remained almost unchanged on annealing.