EFFECT OF BATH pH ON ELECTROLESSNi–PCOATING DEPOSITED ON OPEN-CELL ALUMINUM FOAMS

Abstract

Different electroless Ni – P coatings were deposited on open-cell aluminum foams at various bath pH. The effect of bath pH on the morphology, structure, components, phases and corrosion resistance of the Ni – P coating was studied by scanning electron microscopy (SEM), confocal laser scanning microscope (CLSM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), immersion test and electrochemical polarization measurement, respectively. The experimental results show that the bath pH not only changed the reactivity of the bath, but also had a influence on the microstructure and anticorrosive property of electroless Ni – P coating. The high pH bath raises the thickness of Ni – P coating but decreases the content of phosphorus element in the Ni – P coating. The corrosion resistance of the coated aluminum foams increases when the bath pH rises.