EFFECT OF DIFFERENT ORGANIC ADDITIVES ON SURFACE MORPHOLOGY AND MICROSTRUCTURE OF Zn-Mo COATINGS ELECTRODEPOSITED FROM CITRATE BATHS

The study investigates the impact of various organic additives on the electrodeposition process of zinc-molybdenum (Zn-Mo) coatings on steel substrates, utilizing citrate baths. The objective was to characterize the effects of different cationic, anionic, and nonionic surface-active additives, including polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), and cetyl trimethyl ammonium bromide (CTAB), on the resulting surface morphology and microstructure of the coatings. Employing methods such as wavelength dispersive X-ray fluorescence spectrometry (WDXRF) for deposit composition analysis and atomic force microscopy (AFM) for topography assessment, the impact of these additives was quantitatively and qualitatively analyzed. The results indicated that PEG at 1.5 g/dm3 and Triton X-100 at 0.1 g/dm3 optimized the current efficiency of electrodeposition to 71.4% and 70.7%, respectively. Furthermore, the presence of D-sorbitol significantly reduced grain size and roughness, leading to smoother and more compact coatings compared to samples without additives. This research not only highlights the optimal concentrations for effective additive usage but also illustrates the potential for developing advanced corrosion-resistant coatings through controlled electrodeposition processes.