INTERFACIAL STRUCTURE AND REACTION-MECHANISM OF ALN TI JOINTS/

Bonding of AIN to Ti was performed at high temperatures in vacuum. The bonding temperature ranged from 1323 to 1473 K, while the bonding tim e varied from 7.2 up to 72 ks. The reaction products were examined usi ng elemental analysis and X-ray diffraction. TiN, Ti(3)AIN (tau(1)), a nd Ti(3)AI were observed at the AIN/Ti interface, having various thick ness at different bonding conditions. The thickness of TiN and Ti(3)AI N layers grew slowly with bonding time. On the other hand, growth of t he Ti(3)AI layer followed Fick's law. The activation energy of its gro wth was found to be 146 kJ mol(-1). When thinner Ti foil (20 mu m) was joined to AIN at 1473 K for a long time (39.6 ks), the Ti central lay er has completely consumed and another ternary compound Ti(2)AIN(22) s tarted to form. A maximum bond strength was achieved for an AIN/Ti (20 (m)u m) joint made at 1473 K for 28.8 ks, after which the bond streng th of the joint deteriorated severely.