What are the common types of tungsten electrodes used in GTAW?

The correct answer highlights the common types of tungsten electrodes used in Gas Tungsten Arc Welding (GTAW). These include pure, thoriated, ceriated, and lanthanated tungsten.

Pure tungsten electrodes are often used for welding applications where a non-consumable electrode is required, providing good arc stability and low contamination. Thoriated tungsten electrodes, which contain small amounts of thorium oxide, enhance arc stability and produce lower work function, allowing for easier starting and better performance in various welding positions. Ceriated tungsten electrodes, with cerium oxide content, offer similar benefits to thoriated electrodes but provide more consistent arc stability at lower amperages, making them suitable for welding thin materials. Lanthanated tungsten electrodes are known for their versatile performance across a wide range of conditions, particularly in DC welding and offer improved arc characteristics.

Other options do not represent common tungsten electrodes used in GTAW. Carbide and aluminum electrodes, as well as nickel and chromium electrodes, are not suitable for this application because they are not designed for the high-temperature and non-consumable nature of GTAW. Thus, the characteristics of the electrodes listed in the correct answer demonstrate their applicability and effectiveness in various GTAW scenarios.