Thermo-compression bonding of alumina ceramics to metal.

Authors :: Das, S.
Tiwari, A.N.
Kulkarni, A.R.
Source :: Journal of Materials Science; May2004, Vol. 39 Issue 10, p3345-3355, 11p
Publication Year :: 2004
Abstract: Alumina ceramics and Kovar with aluminum interlayer are pressed together under vacuum at temperatures around 600°C for joining. This process produces mechanically strong ceramic to metal bonds in one step in an economic manner. In order to arrive at the optimum conditions for solid-state bonding, effects of bonding temperature, pressure and time on the bond strength have been studied. Bonding kinetics is also elucidated. Irradiation of 99% Al<subscript>2</subscript>O<subscript>3</subscript> ceramics by 4-5 MV X-rays has been found to increase the bond-strength sharply from 33 to 60 MPa with a dose of 15 k Rads for bonding temperatures around 540°C. The apparent activation energy for the bonding process (Q<subscript>B</subscript>) depends strongly on the type of alumina ceramics. Irradiation of alumina ceramics (99%), prior to joining with Kovar, accelerates the solid-state bonding by reducing (Q<subscript>B</subscript>) from 209 to 76 kJ/mole. [ABSTRACT FROM AUTHOR]