Effect of the electrodeposition conditions on the morphology, composition and physicomechanical properties of Co-Mo-P alloys

By means of electron microscopy, EDX analysis, and tribotesting, there is found a correlation between the composition, morphology, and properties of Co-Mo-P alloy coatings deposited at direct current from a citrate electrolyte containing ammonium hypophosphite in a current density range of 1–15 A/dm2, at temperatures of 28 and 60°C, and pH of 4–6. It is shown that the electrolyte pH increase from 4 to 6 leads to a decrease in the phosphorus content and to an increase in the molybdenum concentration in the electrodeposits. A direct correlation between the microhardness and the wear resistance of electrodeposits and the phosphorus content in coatings is shown.