EFFECT OF ANNEALING ON MICROSTRUCTURE AND CORROSION PERFORMANCE OF ADB AND ALB ALLOYS

Microstructure and corrosion performance of admiralty brass (adb) and aluminum brass (alb) alloys afterpassing different annealing heat treatments were investigated using optical and scanning electron microscope, energydispersive x-ray spectroscopy (eds), x-ray diffraction (xrd), dc polarization measurements and electrochemicalimpedance spectroscopy (eis). the results showed that heat treating of alb caused gradient in aluminumconcentration across the grains whose increased with increasing of annealing temperature. on the other hand,corrosion current density (icorr) of adb in 3.5%nacl media decreased with increasing of recrystallization, while albshowed corrosion behavior inconsistent with adb. the impedance measurements showed that corrosion rate of adbdecreased with increasing of exposure time from 0 to 15 days which could be related to the formation of sno2 surfacefilm and the sn-rich phases. while polarization resistance of alb decreased by passing days in the corrosive mediawhich could be associated to establishing of differential aluminum concentration cells.