Cobalt based superalloys have been crucial in turbojet and gas turbine aircraft engines mainly because they combine exceptional high temperature strength, creep resistance, and oxidation or corrosion resistance under the intense conditions of the hot section (combustion chamber, turbine nozzles & blades).

More specifically, cobalt alloys retain strength at elevated temperatures up to and often beyond 1000 °C, resist deformation under long‐term load (creep), and form stable protective oxide scales (often chromium‐rich) that protect against oxidation from hot combustion gases. These qualities allow turbine components to work longer without failure, reducing maintenance, improving reliability and enabling higher engine operating temperatures, which in turn improves engine efficiency.

Beyond aircraft engines, cobalt alloys see industrial application wherever similarly harsh conditions prevail. Key areas are:

Power generation or gas turbines: turbines for electricity generation, compressor components, combustion chambers.

Wear resistant & hard facing applications: the Stellite group of Cobalt - Chromium (and with W, Mo, etc.) alloys are used for tools, blades, valve seats, parts exposed to abrasion, and erosion.

Chemical processing & petrochemical equipment: valves, piping, pump parts subject to corrosive media and high temperatures.

Medical implants: certain cobalt-chromium - molybdenum alloys are used for hip or knee prostheses and dental prosthetics, they combine biocompatibility, corrosion resistance, and wear resistance.

Overall, cobalt alloys while heavier than some alternatives, excel in the hottest, most demanding parts of turbomachinery and in any industrial setting requiring material stability under high thermal, mechanical, and chemical stress.