Cementite, also known as iron carbide (Fe₃C), is a hard, brittle compound formed from iron and carbon. It typically occurs in steel and cast iron, contributing to their mechanical properties. Cementite plays a crucial role in the microstructure of these materials, influencing hardness and wear resistance. In the context of metallurgy, cementite is often found in the iron-carbon phase diagram, which illustrates the different phases and transformations that occur in iron alloys. Its presence can affect the heat treatment processes, making it essential for engineers and metallurgists to understand its behavior in various applications.