US 11,920,253 B2
Methods of controllable interstitial oxygen doping in niobium
Ari D. Palczewski, Westport, CT (US); Eric M. Lechner, Newport News, VA (US); and Charles E. Reece, Yorktown, VA (US)
Assigned to Jefferson Science Associates, LLC, Newport News, VA (US)
Filed by JEFFERSON SCIENCE ASSOCIATES, LLC, Newport News, VA (US)
Filed on May 3, 2022, as Appl. No. 17/735,172.
Claims priority of provisional application 63/189,530, filed on May 17, 2021.
Prior Publication US 2022/0364254 A1, Nov. 17, 2022
Int. Cl. C25D 11/26 (2006.01); C23C 8/12 (2006.01); C22F 1/02 (2006.01); C22F 1/18 (2006.01)
CPC C25D 11/26 (2013.01) [C22F 1/02 (2013.01); C22F 1/18 (2013.01); C23C 8/12 (2013.01)] 1 Claim
OG exemplary drawing
 
1. A method for increasing the interstitial oxygen as a function of depth into the surface of an article of niobium (Nb), comprising:
preparation of a surface oxide on the surface of the article of niobium;
vacuum heat treating at a constant temperature of 280 to 330° C. for 0.5 to 3 hours to dissociate the surface oxide and diffuse oxygen into the surface niobium matrix;
regrowing a surface oxide by exposing the Nb cavity to room atmosphere; and
regrowing the surface oxide until a secondary ion mass spectrometry (SIMS) depth profile verifies the O concentration of the article of niobium is at least 1000 atomic parts per million.