Ceramic materials can exhibit which structural possibilities?

• A. Only crystalline
• B. Only amorphous
• C. Crystalline, partly crystalline, or amorphous
• D. Metallic bonding with ductility

Answer: (C)

Ceramic materials can have a range of atomic arrangements from highly ordered to completely disordered, and even mixtures of the two. They can be fully crystalline, where atoms sit in a long-range repeating pattern; fully amorphous, where there is no long-range order as in glasses; or partially crystalline, where crystalline grains are present within an amorphous or glassy matrix (glass-ceramics produced by controlled crystallization). This versatility is what makes the statement that ceramics can be crystalline, partly crystalline, or amorphous the most accurate. Note that ceramics are typically bonded ionically or covalently rather than by metallic bonds, which is why they are usually hard and brittle rather than ductile.