Chromium (Cr) is a polycrystalline metallic substrate that is commonly used in various applications such as electrical contacts, magnetic storage devices, and as a corrosion-resistant coating. Due to its high melting point, good electrical conductivity, and high reflectivity, it is also used as a substrate in optical systems. However, chromium is also known to be brittle, which can be a drawback in certain applications. To overcome this limitation, it is often alloyed with other metals to enhance its mechanical properties.