The role of electrolyte pH on phase evolution and magnetic properties of CoFeW codeposited films

In this research, nanocrystalline Co-Fe-W alloy coatings were electrodeposited from a citrate-borate bath. The influence of electrolyte pH on the morphology, microstructure and magnetic properties of these films was also studied. By increasing pH value, the amount of iron content increased from 30 to 55 wt.% which indicates anomalous fashion at higher pH electrolytes. X-ray diffraction patterns showed that the structure of these films depend on electrolyte pH effectively. However, two-phase structure coatings showed smaller average grain size compared with one- phase solid solutions. Vibrating sample magnetometer measurements indicated that the coercivity of the coatings was in the range of 21-76 Oe. However, the highest pH value produced coating with superior magnetic behaviour. Microhardness of the coatings reached its maximum value at about 260HV which is referred to the highest tungsten content.