Heating white cast iron above causes the formation of austenite in crystals of primary cementite. Depending on alloy composition, a layering of ferrite and cementite, called pearlite, may form. The softer core is some combination of ferrite and cementite, such as pearlite. Further heating reduces the martensite even more, transforming the unstable carbides into stable cementite. It is mostly found with cementite or pearlite in a range of cast irons. The cementite which precipitates from the melt forms as relatively large particles. Austenite is formed by diffusion of carbon atoms from cementite into ferrite. This austenisation of white iron occurs in primary cementite at the interphase boundary with ferrite. A fine non-lamellar structure, bainite commonly consists of cementite and dislocation-rich ferrite. It can be wear-resistant because of a strong lamellar network of ferrite and cementite. When given more time, stable microconstituents can form&colon; ferrite and cementite. "White" cast irons contain their carbon in the form of cementite, or iron carbide (FeC). When slowly cooling a hypereutectoid steel, the cementite will begin to crystallize first. No large inclusions of cementite will form at the boundaries in hypoeuctoid steel. The best known is cementite, FeC, which is present in steels.