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 time varied from 7.2 up to 72 ks. The reaction products were examined using elemental analysis and X-ray diffraction. TiN, Ti(3)AIN (tau(1)), and Ti(3)AI were observed at the AIN/Ti interface, having various thickness at different bonding conditions. The thickness of TiN and Ti(3)AIN layers grew slowly with bonding time. On the other hand, growth of the Ti(3)AI layer followed Fick's law. The activation energy of its growth 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 layer has completely consumed and another ternary compound Ti(2)AIN(22) started 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 strength of the joint deteriorated severely.