Which material category is used for GTAW nozzles?

• A. Steel
• B. Glass
• C. Ceramic such as alumina or silicon nitride (opaque)
• D. Plastic

Answer: (C)

In GTAW, the nozzle that directs shielding gas must withstand high heat and keep the welding current from arcing into the nozzle. Ceramic materials like alumina (aluminum oxide) or silicon nitride are ideal because they combine very high melting points and excellent thermal stability with electrical insulation. This means the nozzle can endure the intense heat near the arc while preventing any electrical conduction to the torch body, which helps maintain a safe, stable arc and consistent gas coverage.

Ceramics also hold up under the rapid temperature changes and erosion from gas flow, shaping a precise inner passage for smooth, uniform shielding gas delivery. Glass would crack or deform under heat, steel would conduct electricity and could contaminate the weld area, and plastic would melt. So the ceramic category best fits the requirements for GTAW nozzles.