Why are ceramics hard and brittle?
Ceramics tend to be strong but brittle because of the ionic bonding present between the metal and non-metal components of the material. Ionic bonds are very strong and require a relatively large amount of energy to break. However, once enough energy is applied to break the bonds, they break completely, making the material brittle. Covalently bonded materials like polymers are far less brittle because the covalent bonds can stretch during plastic deformation.
