Cobalt containing superalloys contribute to the longevity of aeroplanes.
Long-life in Service
Cobalt has a key role to play in the longevity of many products due to the hard wearing, wear resistant and oxidation free properties that it confers to applications.
Increasing the life in service of applications is important for sustainability in terms of lowering the consumption of raw materials, and together with recovery and recycling steps, this can help to reduce the amount of waste generated at the end-of-life phase. Furthermore, the energy expenditures during service life, and in recycling and retooling applications, can be much less compared to manufacture of new products.
Cobalt is used in many different alloy applications including, wear-resistant alloys, superalloys, powder metallurgy, and hard metal. Cobalt gives these alloys an increased resistance to wear, corrosion, and heat. These properties give the alloys a longer life in service as well as making them more reliable. A key sector for cobalt containing superalloys for example is aerospace where these properties are vital for reliable and efficient turbines, which helps to ensure the safety for passengers. Other examples include cobalt alloys for dental and medical devices where cobalt confers biocompatibility.
Cobalt in rechargeable batteries
Cobalt is also important for maintaining the life of rechargeable batteries. Previous versions of lithium ion batteries that did not utilise cobalt often overheated, failed and even ignited. These problems arise due to dendrite formations piercing the membrane between the cathode and the anode.
By including cobalt in the cathode, the lithium ions are prevented from forming dendrites by bonding to the cobalt. Preventing the formation of dendrites ultimately leads to the longer-life of the battery.
Cobalt prevents dendrites forming within lithium-ion batteries thereby increasing the life in service.
Cobalt also prolongs the life in service of cylindrical alkaline batteries. During storage, the inner surface of the battery becomes lightly oxidised over time. Due to the battery case being the current conductor, the higher surface resistance caused by the oxidation leads to higher heat generation and less power. Eventually, the battery will then need to be replaced for the application to be powered efficiently. By adding cobalt to the inner surface of the battery, oxidation is reduced pro-longing the life in service of the battery. In this role, the only possible alternatives to cobalt chemically speaking are gold and silver however for economic reasons these are not viable alternatives.