Bright color coatings for electronic devices
An electronic device may include conductive structures such as conductive housing structures. A high-brightness, visible-light-reflecting coating may be formed on the conductive structures. The coating may have adhesion and transition layers and an uppermost coloring layer on the adhesion and transition layers. At least the uppermost coloring layer may be deposited using a high impulse magnetron sputtering (HiPIMS) process. The uppermost coloring layer may include a TiCrN film, a TiCrCN film, a TiCN film, or a metal nitride film that contains Ti, Zr, Hf, or Cr. The coating may exhibit a high-brightness gold color.
1. Apparatus comprising:
a conductive substrate; and
a coating on the conductive substrate and having a color, the coating comprising:
adhesion and transition layers, and
an uppermost layer on the adhesion and transition layers, the uppermost layer comprising a TiCrN film, wherein the coating has an L* value greater than 75 in a CIELAB color space, an a* value between 0 and 5 in the CIELAB color space, and a b* value between 10 and 15 in the CIELAB color space.
2. The apparatus of claim 1 , wherein the TiCrN film is opaque.
3. The apparatus of claim 1 , wherein the TiCrN film has a thickness between 0.1 and 1.0 microns.
4. The apparatus of claim 1 , wherein an atomic percentage of Ti atoms in the TiCrN film is greater than 40% and less than 60%.
5. The apparatus of claim 4 , wherein an atomic percentage of Cr atoms in the TiCrN film is greater than 5% and less than 20%.
6. The apparatus of claim 4 , wherein an atomic percentage of N atoms in the TiCrN film is greater than 25% and less than 40%.
7. The apparatus of claim 1 , wherein an atomic percentage of Cr atoms in the TiCrN film is greater than 5% and less than 20%.
8. The apparatus of claim 7 , wherein an atomic percentage of N atoms in the TiCrN film is greater than 25% and less than 40%.
9. The apparatus of claim 1 , wherein the adhesion and transition layers comprise a Cr seed layer on the conductive substrate and a CrN transition layer on the Cr seed layer, the TiCrN film being layered on the CrN transition layer.
10. The apparatus of claim 1 , wherein the apparatus comprises a wristwatch and the conductive substrate comprises a conductive housing wall of the wristwatch.
11. The apparatus of claim 1 , wherein the TiCrN film is deposited on the adhesion and transition layers using a high impulse magnetron sputtering (HiPIMS) process.
12. The apparatus of claim 11 , wherein the adhesion and transition layers are deposited on the conductive substrate using a non-HiPIMS magnetron sputtering process.
13. An electronic device comprising:
a conductive structure; and
a coating on the conductive structure and having a color, the coating comprising:
adhesion and transition layers, wherein the adhesion and transition layers comprise a chromium (Cr) layer on the conductive structure and a chromium nitride (CrN) layer on the Cr layer, and
a titanium chromium nitride (TiCrN) layer on the adhesion and transition layers, wherein the TiCrN layer is an outermost layer of the coating.
14. The electronic device of claim 13 , wherein the coating has an L* value greater than 75 in a CIELAB color space, an a* value between 0 and 5 in the CIELAB color space, and a b* value between 10 and 15 in the CIELAB color space.
15. The electronic device of claim 13 , wherein the conductive structure comprises a conductive housing wall.
16. The electronic device of claim 13 , wherein the conductive structure comprises a button.
17. A wearable electronic device comprising:
a conductive housing wall; and
a coating on the conductive housing wall and having a color, the coating comprising:
a chromium (Cr) layer on the conductive housing wall,
a chromium nitride (CrN) layer on the Cr layer, and
a titanium chromium nitride (TiCrN) layer on the CrN layer, wherein the TiCrN layer is an outermost layer of the coating.
18. The wearable electronic device of claim 17 , wherein the wearable electronic device comprises a wristwatch.