Super alloys have good creep and oxidation resistance. They can be formed in different shapes, and used in environments with very high temperatures and mechanical stress, and also where high surface stability is required. They consist of a number of elements in a variety of combinations to achieve the desired result. Solid-solution hardening, work hardening, and precipitation hardening are performed to increase their strength. Cobalt-based, nickel-based, and iron-based alloys are three groups of super alloys. They all can be used at temperatures above 540°C (1000°F). Incoloy 903 is a nickel-cobalt alloy added with niobium to increase its oxidation resistance and strength.