Inorganic nonmetallic materials that are hard and brittle are called?

• A. Polymers
• B. Composites
• C. Metals
• D. Ceramics

Answer: (D)

Hard, brittle behavior is a hallmark of ceramics. These are inorganic nonmetallic materials—think oxides, nitrides, and carbides—that have strong ionic or covalent bonds and rigid crystal structures. That bond strength and structure give high hardness and a high resistance to denting, but they resist plastic deformation, so cracks propagate easily under stress, causing brittle failure. Ceramics also tend to have high melting points and excellent thermal stability, and they generally act as insulators or insulators with high temperature tolerance.

Polymers are typically organic and more ductile and softer; metals are malleable and ductile rather than brittle; composites are mixtures designed for tailored properties and can vary widely. The combination of inorganic and nonmetallic nature with rigid bonding makes ceramics the best match for hard and brittle materials.