Metal fastener

1. A metal fastener comprising an expanded head and a smooth shank extending in an axis of revolution, characterized in that the shank comprises at least one portion treated by anode oxidation and at least one lubricating portion, wherein the at least one portion treated by anode oxidation and at least one lubricating portion are disposed continuously along the axis of revolution (A) of the fastener and wherein the at least one lubricating portion has a side portion disposed continuously along the axis of revolution and anode oxidation extends in a circumferential direction away from the side portion.

2. A metal fastener according to claim 1 , wherein the at least one portion treated by anode oxidation and the lubricating portion are disposed parallel to the axis of revolution (A) of the fastener.

3. A metal fastener according to claim 2 , wherein at least two lubricating portions are disposed in diametrically opposite fashion relative to the axis of revolution (A) of the fastener.

4. A metal fastener according to claim 1 , wherein the lubricating portion is a solid lubricating film or an organic resin coating comprising aluminum pigments.

5. A metal fastener according to claim 1 , where in the shank is cylindrical.

6. A metal fastener according to claim 1 , further including a locking portion comprising a thread.

7. The metal fastener of claim 1 wherein the at least one lubricating portion extends a distance X along the axis of revolution (A) less than a length of the shank.

8. A fixing element for securing components of an assembly, comprising:

a metal rod comprising a cylindrical shaft and an end, the metal rod comprising:

a first region that is at least partially surface-treated by means of anode oxidation; and

a second region coated over at least a portion with a lubricating coating disposed continuously along the axis of revolution (A) of the fastener and wherein the lubricating coating has a side portion disposed continuously along the axis of revolution and anode oxidation extends in a circumferential direction away from the side portion.

9. The fixing element of claim 8 , wherein the cylindrical shaft comprises:

at least a first strip that extends in the length of the cylindrical shaft and which is surface-treated by means of anode oxidation; and

at least a second strip that extends in the length of the cylindrical shaft and which is coated with the lubricating coating.

10. The fixing element of claim 9 , wherein the cylindrical shaft comprises:

a plurality of first strips that are surface-treated by means of anode oxidation; and

a plurality of second strips that are coated with a lubricating coating, the first and second strips extending over angular sectors that are distributed around the periphery of the cylindrical shaft.

11. The fixing element of claim 10 , wherein the first and second strips are distributed in a substantially uniform manner around the periphery of the cylindrical shaft.

12. The fixing element of claim 10 wherein the cylindrical shaft comprises first strips that are surface-treated by means of anode oxidation and each over three angular sectors of a first angle, respectively, and that are separated in pairs by means of a second strip that is covered with the lubricating coating and extends over an angular sector of a second angle.

13. The fixing element of claim 10 , wherein the cylindrical shaft comprises two first strips that are surface-treated by means of anode oxidation and that extend over two angular sectors between substantially 90 and 150°, respectively, and two second strips which are covered with a lubricating coating that extends over two angular sectors between substantially 30 and 90°, respectively.

14. The fixing element of claim 10 , wherein the rod is at least partially surface-treated by means of sulphuric anode oxidation.

15. The fixing element of claim 14 , wherein lubricating coating (R) is a coating comprising phenolic resin.

16. An aircraft assembly, comprising:

a first component;

a second component; and

a metal rod comprising a cylindrical shaft and an end for securing the first and second components, the metal rod comprising:

a first region that is at least partially surface-treated by means of anode oxidation; and

a second region coated over at least a portion thereof with a lubricating coating disposed continuously along the axis of revolution (A) of the fastener and wherein the lubricating coating has a side portion disposed continuously along the axis of revolution and anode oxidation extends in a circumferential direction away from the side portion.

17. Aircraft comprising at least one assembly according to claim 16 .

18. The aircraft assembly of claim 16 , wherein the cylindrical shaft comprises:

at least a first strip that extends in the length of the cylindrical shaft and which is surface-treated by means of anode oxidation; and

at least a second strip that extends in the length of the cylindrical shaft and which is coated with the lubricating coating.

19. The aircraft assembly of claim 18 wherein the cylindrical shaft comprises;

a plurality of first strips that are surface-treated by means of anode oxidation; and

a plurality of second strips that are coated with a lubricating coating, the first and second strips extending over angular sectors that are distributed around the periphery of the cylindrical shaft.

20. The aircraft assembly of claim 19 , wherein the oxidation is a sulfur anode oxidation.

21. The aircraft assembly of claim 20 , wherein the metal rod comprises a cylindrical shaft and an end, and wherein a section between the cylindrical shaft and the end is frustroconical.

22. The aircraft assembly of claim 20 wherein the anode oxidation has a thickness that allows conductivity.

23. The aircraft assembly of claim 20 wherein the lubricant coating is substantially 5 microns thick.

24. The aircraft assembly of claim 20 wherein the metal rod is titanium.