ELECTRON-MICROSCOPE OBSERVATIONS ON ELECTROLYTIC NI-MO-FE COATINGS

Selected Ni-Mo-Fe coatings were electrodeposited from ammoniacal citra te baths by varying the plating parameters. Their surfaces were examin ed by scanning electron microscopy for topography and SE imaging. Obse rved electrocatalytic, corrosion and optical properties of the coating s were found to be dependent on surface structure. The results were al so rued to understand the influence of electrodeposition variables. Th e plating diameters were found to have strong influence on the surface structure. Increases in deposition CD resulted in phase segregation i n these materials. Also it was confirmed that increases in molybdenum content of the plating bath introduced heterogeneity in the plated sam ples with occurrence of more than one phase. Multinucleation in crysta l structure was observed in samples electrodeposited at near neutral p H levels, again due to increased molybdenum content. The coatings reve al network formation at 300 degrees C. Inclusion of Mn was helpful in obtaining homogeneous deposits.