US 12,064,812 B2
Additive manufacturing of refractory metals with reduced level of contamination
Vera K. Jüchter, Hanau (DE); and Bernd Spaniol, Hammersbach (DE)
Assigned to HERAEUS DEUTSCHLAND GMBH & CO. KG, Hanau (DE)
Filed by Heraeus Deutschland Gmbh & Co. KG, Hanau (DE)
Filed on Apr. 7, 2021, as Appl. No. 17/224,885.
Claims priority of application No. 20168652 (EP), filed on Apr. 8, 2020.
Prior Publication US 2021/0316366 A1, Oct. 14, 2021
Int. Cl. B22F 10/28 (2021.01); B22F 1/05 (2022.01); B22F 5/00 (2006.01); B22F 9/08 (2006.01); B22F 9/16 (2006.01); B33Y 10/00 (2015.01); B33Y 70/00 (2020.01); B33Y 80/00 (2015.01)
CPC B22F 10/28 (2021.01) [B22F 1/05 (2022.01); B22F 5/007 (2013.01); B22F 9/08 (2013.01); B22F 9/16 (2013.01); B33Y 10/00 (2014.12); B33Y 70/00 (2014.12); B33Y 80/00 (2014.12); B22F 2301/20 (2013.01); B22F 2304/10 (2013.01)] 15 Claims
 
1. An additive manufacturing method for producing a molding, the method comprising the steps of:
a) applying a first layer of a refractory metal powder onto a substrate, wherein the refractory metal powder comprises a refractory metal selected from niobium and tungsten,
b) selectively melting at least a portion of the first layer by means of an electron beam, wherein the melting takes place with a volume energy of at least 40 J/mm3,
c) cooling the melt below the solidification temperature to obtain a first material layer,
d) applying a further layer of the refractory metal powder onto the first material layer,
e) selectively melting at least a portion of the further layer by means of an electron beam, wherein the melting takes place with a volume energy of at least 40 J/mm3,
f) cooling the melt below the solidification temperature to obtain a material layer,
g) repeating steps d)-f) until the molding is completely constructed,
wherein
the refractory metal powder has an oxygen content of at least 500 mol ppm,
the constructed molding has an oxygen content which is at least 15% lower than the oxygen content of the refractory metal powder, and
the first and further layer do not contain substances that react with oxygen.