Compared to thorium tungsten, EWZr electrodes offer what difference?

• A. They emit electrons freely but to a lesser degree
• B. They have better emission and are not easily melted
• C. They are radioactive
• D. They cannot be used with AC

Answer: (A)

Electron emission at the electrode tip drives arc initiation in GTAW. Thorium-containing tungsten has very high emission because thorium lowers the work function, making arc starting easier and maintenance more forgiving at lower amperage. EWZr electrodes don’t include thorium, so their electron emission is still good but not as strong as thorium-tungsten. They’re designed for durability and stable arc, but the emission level is lower compared to thorium-containing electrodes. That’s why the difference is described as emitting electrons freely but to a lesser degree.