Advanced materials — what are cermets? Cermets are best classified as which type of engineering materials?

Introduction / Context:
Cermets (ceramic–metal composites) are used where high-temperature strength, wear resistance, and corrosion resistance are needed, e.g., cutting tools, turbine components, and protective parts.

Given Data / Assumptions:

• Cermets combine ceramic phases (e.g., TiC, TiN) with metallic binders (e.g., Co, Ni).
• They must retain integrity at elevated temperatures.

Concept / Approach:
Because ceramics are refractory (high melting points, thermal stability) and the composite maintains these traits, cermets are broadly categorized as refractory materials. They are not fully metallic; though they can be abrasive and sometimes reinforced, their defining engineering role is refractory service.

Step-by-Step Solution:
Identify composition: ceramic + metal = cermet.Connect application: high-temperature, wear/oxidation resistance → refractory classification.Hence, select “Refractory.”

Verification / Alternative check:
Applications in cutting inserts and nozzles confirm high-temperature capability and wear resistance typical of refractory materials.

Why Other Options Are Wrong:

• Reinforced: too generic; many composites are reinforced.
• Abrasive: some cermets are abrasive, but that is not the defining category.
• Fully metallic: incorrect by definition; cermets include ceramics.

Common Pitfalls:

• Equating “composite” with “reinforced” without considering functional classification.

Final Answer:
Refractory