Mechanical Properties of Electroformed Nickel Cobalt Alloys

Mechanical properties of nickel-cobalt alloys (0-10% Co) electroformed with low internal stress in sulfamate-based solutions were investigated in as deposited and heat treated conditions. It was demonstrated that alloy properties can be modified by selecting deposition conditions and alloy composition. Recommendations on alloy selection are made based on application requirements. The higher strength and hardness of nickel-cobalt alloy electrodeposits compared to nickel stimulates their increasing use in electroforming and as engineering coatings. Many advanced electroformed products such as bellows, contacts, optical and nanofluidic molds can only be produced consistently if the deposits’ properties are well understood and properly controlled by the process engineer. This paper examines the properties of nickel-cobalt alloys obtained in sulfamate-based electrolytes and, specifically, the relationships between a deposit’s composition, internal stress, mechanical properties and thermal stability. Once such relationships are established, the electroformer can use them to tailor the deposit properties to the requirements dictated by the application and assure that produced components will consistently meet their specifications.