US 12,448,675 B2
Low temperature titanium hardening
Thomas Lundin Christiansen, Frederikssund (DK); Morten Stendahl Jellesen, Søborg (DK); Marcel A. J. Somers, Billund (DK); and Andreas Frederik Kielsholm Körkel, Græsted (DK)
Assigned to ELOS MEDTECH PINOL A/S, Gørløse (DK)
Appl. No. 17/637,431
Filed by ELOS MEDTECH PINOL A/S, Gørløse (DK)
PCT Filed Aug. 21, 2020, PCT No. PCT/EP2020/073556
§ 371(c)(1), (2) Date Feb. 22, 2022,
PCT Pub. No. WO2021/037757, PCT Pub. Date Mar. 4, 2021.
Claims priority of application No. 19193358 (EP), filed on Aug. 23, 2019.
Prior Publication US 2022/0275495 A1, Sep. 1, 2022
Int. Cl. C23C 8/16 (2006.01)
CPC C23C 8/16 (2013.01) 23 Claims
OG exemplary drawing
 
1. A method of oxygen hardening a Group IV metal, the method comprising the steps of:
providing a workpiece of a Group IV metal in its final shape;
oxidising the Group IV metal over an oxidising duration of at least 10 minutes in an oxidising atmosphere at a first temperature to provide a non-stratified Group IV metal oxide on the surface of the workpiece using a gaseous oxidising species selected from CO2, N2O and combinations of CO2 and N2O, the gaseous oxidising species having an upper temperature limit of up to 800° C. wherein the first temperature is in the range of 500° C. and the upper temperature limit of the gaseous oxidising species;
diffusing oxygen from the non-stratified Group IV metal oxide into the Group IV metal in an inert atmosphere at a second temperature in the range of 500° C. to 800° C. and at a partial pressure of the gaseous oxidising species of up to 10−4 mbar over a diffusive duration of at least 2 hours to provide a superficial diffusion zone comprising oxygen in solid solution.