A tantalum or tantalum alloy which contains pure or substantially pure tantalum and at least one metal element selected from the group consisting of Ru, Rh, Pd, Os, Ir, Pt, Mo, W and Re to form a tantalum alloy that is resistant to aqueous corrosion. The invention also relates to the process of preparing the tantalum alloy.

A vacuum arc remelting system for forming an ingot from an electrode is provided that includes a crucible assembly configured to accommodate the electrode and the ingot, an electromagnetic energy source arranged about the crucible assembly, and a lift mechanism operable to move the electromagnetic energy source along a longitudinal axis of the crucible assembly. A magnetic field generated by the electromagnetic energy source is localized to an arc region during remelting, and in one form, the electromagnetic energy source is a coil assembly having a magnetic core and a plurality of coil pairs wrapped around the core, wherein the coil assembly is operable to generate a magnetic field from the coil based on electric current flowing in the plurality of coil pairs.

A method for producing a metal ingot by using an electron-beam melting furnace including an electron gun and a hearth that accumulates a molten metal of a metal raw material, in which, in a downstream region between an upstream region in which the metal raw material is supplied onto the surface of the molten metal and a first side wall, an irradiation line is disposed so as to block a lip portion and so that two end portions are positioned in the vicinity of the side wall of the hearth. A first electron beam is radiated onto the surface of the molten metal along the irradiation line, such that the surface temperature (T2) of the molten metal along the irradiation line is made higher than the average surface temperature (T0) of the entire surface of the molten metal in the hearth.

A method for producing a metal ingot by using an electron-beam melting furnace including an electron gun and a hearth that accumulates a molten metal of a metal raw material, in which, in a downstream region between an upstream region in which the metal raw material is supplied onto the surface of the molten metal and a first side wall, an irradiation line is disposed so as to block a lip portion and so that two end portions are positioned in the vicinity of the side wall of the hearth. A first electron beam is radiated onto the surface of the molten metal along the irradiation line, such that the surface temperature (T2) of the molten metal along the irradiation line is made higher than the average surface temperature (T0) of the entire surface of the molten metal in the hearth.

A tantalum or tantalum alloy which contains pure or substantially pure tantalum and at least one metal element selected from the group consisting of Ru, Rh, Pd, Os, Ir, Pt, Mo, W and Re to form a tantalum alloy that is resistant to aqueous corrosion. The invention also relates to the process of preparing the tantalum alloy.

A tantalum or tantalum alloy which contains pure or substantially pure tantalum and at least one metal element selected from the group consisting of Ru, Rh, Pd, Os, Ir, Pt, Mo, W and Re to form a tantalum alloy that is resistant to aqueous corrosion. The invention also relates to the process of preparing the tantalum alloy.

An electron beam (EB) gun assembly for an EB furnace is provided. The EB gun assembly includes an EB gun-frame assembly including a skeleton frame and at least one EB gun mounted to the skeleton frame, and the EB gun-frame assembly is configured to rigidly mount onto a first EB chamber lid and melt material in a first EB chamber and be removed and rigidly mount onto a second EB chamber lid and melt material in a second EB chamber. In some forms, the EB gun assembly includes at least one mounting frame and the at least one EB gun is mounted to the at least one mounting frame and the at least one mounting frame is mounted to the skeleton frame.

A tantalum or tantalum alloy which contains pure or substantially pure tantalum and at least one metal element selected from the group consisting of Ru, Rh, Pd, Os, Ir, Pt, Mo, W and Re to form a tantalum alloy that is resistant to aqueous corrosion. The invention also relates to the process of preparing the tantalum alloy.

A tantalum or tantalum alloy which contains pure or substantially pure tantalum and at least one metal element selected from the group consisting of Ru, Rh, Pd, Os, Ir, Pt, Mo, W and Re to form a tantalum alloy that is resistant to aqueous corrosion. The invention also relates to the process of preparing the tantalum alloy.

An apparatus for the gasification and vitrification of waste comprises a plasma arc furnace provided with two movable graphite electrodes. The furnace includes an air-cooled bottom electrode adapted for transferring the current through a slag melt. The furnace is entirely sealed and is also provided with gas tight electrode seals adapted to control reducing conditions inside the furnace. An electrical circuit is further provided, which is adapted for switching from transferred io non-transferred modes of heating, thereby allowing the furnace to be restarted in case of slag freezing.