In the formation of cermets, the ratio of ceramic material to metallic material is usually 80:20. Which of the following is a cermet ?

ANS:D - Tungsten carbide

A cermet is a composite material made up of a combination of ceramic (cer) and metallic (met) materials. The typical ratio of ceramic to metallic material in cermets is around 80:20. Among the options provided:

• Zirconia and alumina are ceramic materials.
• Bakelite is a type of thermosetting plastic (polymer).
• Tungsten carbide is a cermet.

Therefore, the correct answer is Tungsten carbide. It consists of tungsten carbide grains (ceramic) embedded in a metallic binder phase, typically cobalt or nickel. This combination provides tungsten carbide with properties that make it suitable for applications requiring high hardness, wear resistance, and strength.