Refractory metal and alloy refining by laser forming and melting
View Patent ↗A process to chemically refine and consolidate tantalum, niobium and their alloys to a fabricated product of net shape or near-net shape with higher throughput, more consistency, and lower manufacturing costs compared to prior art routes or rejuvenate damaged and deteriorated refractory metal parts. Powder metal is loaded into hoppers to be fed into laser forming/melting equipment. A suitable substrate is loaded into a laser forming/melting chamber onto which the powder will be deposited and consolidated in a point-scan process. As the powder is fed onto successive points of the surface of the substrate in linear traces, the laser is used to heat and partially melt the substrate and completely melt the powder. A combined deposition and melt beam traces the substrate surface repeatedly over a selected area to build up a dense coating of controlled microstructure in multiple layers. A fully dense deposit is built up that becomes the desired shape.
1. A process for making a refractory metal part comprising:
(a) loading refractory powder metal particles into a hopper for feeding into a laser additive chamber, wherein the refractory metal particles are selected from the group consisting of tantalum, Re, W, Mo, W alloys, Mo alloys, Re alloys, niobium, tantalum alloys and niobium alloys.
(b) loading a substrate into the laser additive chamber,
(c) feeding the powder metal powders into the additive chamber onto successive points on the substrate in a linear trace,
(d) melting the substrate and the powder with a laser beam and building up multiple coatings of a controlled microstructure,
(e) tracing the substrate over a selected area with a combined deposition and melt beam and building up a coating of a controlled microstructure in multiple layers, and
(f) building up a deposit from the coating and forming a refractory metal part and wherein the refractory metal part is a sputtering target or tube perform or furnace part preform.
2. The process of claim 1 , wherein the deposit built up from the coating is a fully dense deposit.
3. The process of claim 1 , wherein the process is carried out under inert conditions.
4. The process of claim 3 , wherein the conditions include argon, at or near or below atmospheric pressure.
5. The process of claim 1 , wherein the process is carried out under a hard vacuum.
6. The process of claim 1 , wherein the laser beam generates sufficiently high heat to create conditions that purify the powder and the refractory metal part.
7. The process of claim 1 , wherein the refractory metal part is a sputtering target.
8. The process of claim 1 , wherein the refractory metal powder particles are tantalum or tantalum alloys.
9. The process of claim 1 , wherein the substrate is a tantalum plate.
10. The process of claim 1 , wherein the refractory metal part is a sputter plate bonded to a backing plate.
11. The process of claim 1 , wherein the sputter plate is a tantalum sputter plate, and the refractory metal particles are tantalum or tantalum alloys.
12. A process for making a refractory metal part comprising:
(a) loading powder metal particles into a hopper for feeding into a laser additive chamber,
(b) loading a tantalum substrate into the laser additive chamber,
(c) feeding the powder metal powders into the additive chamber onto successive points on the substrate in a linear trace,
(d) melting the substrate and the powder with a laser beam and building up multiple coatings of a controlled microstructure,
(e) tracing the substrate over a selected area with a combined deposition and melt beam and building up a coating of a controlled micro structure in multiple layers, and
(f) building up a deposit from the coating and forming a tantalum sputtering target.
13. The process of claim 12 , wherein the refractory metal particles are selected from the group consisting of tantalum and tantalum alloys.