Why are water-cooled copper clamps used in direct-resistance sintering?

In the context of niobium processing, direct-resistance sintering involves heating "green" compacts to extremely high temperatures, typically between 2,100 and 2,300 °C (3,800 and 4,150 °F).1

Water-cooled copper clamps with brazed tungsten facings are used to establish the necessary electrical contact for this process. These clamps are essential because they must conduct the high electrical current required for heating while simultaneously withstanding the intense heat generated during the sintering cycle without melting or degrading. The water-cooling system ensures the clamps remain stable and functional, allowing for the controlled, staged temperature increases needed to facilitate the evaporation of impurities and prevent the sudden, potentially damaging release of gases from the metal.1