US 12,378,664 B2
Metal surface layer treating method, metal assembly and electronic device
Bing Liu, Beijing (CN)
Assigned to Beijing Xiaomi Mobile Software Co., Ltd., Beijing (CN)
Filed by Beijing Xiaomi Mobile Software Co., Ltd., Beijing (CN)
Filed on Mar. 24, 2022, as Appl. No. 17/703,385.
Claims priority of application No. 202111138545.5 (CN), filed on Sep. 27, 2021.
Prior Publication US 2023/0097354 A1, Mar. 30, 2023
Int. Cl. C23C 14/34 (2006.01); C23C 14/06 (2006.01); C23C 14/58 (2006.01); C23C 16/36 (2006.01); C23C 16/50 (2006.01); C23C 16/56 (2006.01); G04B 37/22 (2006.01); G04G 17/08 (2006.01)
CPC C23C 16/36 (2013.01) [C23C 16/50 (2013.01); C23C 16/56 (2013.01); G04B 37/223 (2013.01); G04G 17/08 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A metal assembly comprising:
a metal body; and
a carbon-nitrogen gradient hardening layer covering the metal body, wherein
a hardness of the carbon-nitrogen gradient hardening layer is gradually reduced in a direction from an outside surface to an inside surface thereof,
a thickness of the carbon-nitrogen gradient hardening layer is in the range of 3 μm to 35 μm, and
the carbon-nitrogen gradient hardening layer has a hardness of 896 HV0.01 to 852 HV0.01 at a distance of 0 to 5 μm from a surface thereof.