Influence of Zirconia Incorporation on the Mechanical and Chemical Properties of Ni-Co Alloys

Ni-Co-ZrO2 nano-composites are electrodeposited from sulphamate electrolyte and a comparison is made with Ni-ZrO2 in terms of structure and properties. The Co content in the coatings is in the range of 10-80wt%. The deposition conditions like current density, pH are optimized in terms of microhardness and amounts of ZrO2 incorporated. The micro-hardness studies revealed that the maximum hardness is exhibited by Ni-28Co-2ZrO2 composite. The FESEM study showed a change in morphology from polyhedral to ridge with increase in Co content from 10 to 80wt%. A change in crystal structure from fcc to hcp is also seen. The effect of annealing treatment in terms of microhardness is studied by subjecting the com-posite electroforms to 800℃. The Co rich composite exhibited better stability compared to Ni rich composites. Ni-28Co-2ZrO2 composite exhibited better immersion corrosion resistance while, Ni-ZrO2 composite displayed better elec-trochemical corrosion resistance. The wear studies showed that Ni-10Co-2ZrO2, Ni-28Co-2ZrO2 composites showed better resistance. Thus, it is seen that the coatings can be tailored to suit various applications.