ANNEALING KINETICS AND EMBRITTLEMENT OF ELECTRODEPOSITED COPPER

Two types of 35 gm thick free-standing copper electrodeposits, one ame nable to rapid annealing and the other responding sluggishly to therma l exposure, have been subjected to isothermal anneals at 100-250-degre es-C for up to 200 min. The apparent activation energy calculations fr om changes in mechanical properties yield 8.2 k cals/g atom for a ''re covery'' anneal of foil (i), and 15 k cals/g atom for a ''recrystalliz ation'' anneal of foil (ii). This is in keeping with the values availa ble in the literature for the electro and vapor deposits. Further, the electrodeposits display embrittlement, that is loss of ductility, at elevated temperature (180-degrees-C). The annealing gradually removes embrittlement, the removal rate depends upon the time/temperature para meters of the thermal exposure.