Stud/nut ground apparatus with a tin-zinc coating
Method of manufacturing a ground apparatus and ground apparatus comprising an aluminum nut ( 16 ) having an internal thread and adapted to clamp an eyelet ( 28 ) of an electrical conductor on a corresponding contact area of the stud ( 12 ), wherein the nut ( 16 ) has at least one coating ( 30 ) which contains at least zinc, characterized in that the coating further comprises tin, in that the coating consists of an acid tin-zinc electroplating on the aluminum nut ( 16 ) and is such that the tin is between 60 and 80% by weight of the coating and the tin-zinc coating forms a layer with an average thickness of from about 5 to 16 microns.
1. A nut comprising:
a body of aluminum and partially defining a bore with an internal female thread; and
an outer plated coating comprising tin and zinc and having an average thickness of 5 to 16 microns, and wherein the tin is between 60% and 80% by weight of the outer plated coating.
2. The nut according to claim 1 and further comprising a surface passivation coating or a lubricant coating over the outer plated coating.
3. The nut according to claim 1 , wherein the outer plated coating extends over the internal female thread.
4. The nut according to claim 1 , wherein the zinc is between 20% and 40% by weight of the outer plated coating.
5. The nut according to claim 1 and further comprising an inner coating comprising copper or zinc.
6. The nut according to claim 5 wherein the inner coating has a thickness between 200 nm and 3 microns.
7. A method of manufacturing a ground apparatus, the method comprising the steps of:
providing a nut of aluminum including an internal thread;
pre-treating the nut to degrease or remove any impurities;
coating the nut with an outer layer comprising tin and zinc and having an average thickness of 5 to 16 microns, and wherein the tin is between 60% and 80% by weight of the outer layer; and
post-treating the nut.
8. The method according to claim 7 , wherein the step of coating the nut with an outer layer includes electroplating the nut by acid tin-zinc electroplating.
9. The method according to claim 7 , wherein the post-treating step includes coating the nut with a surface passivation layer or a lubricant over the outer layer.
10. The method according to claim 7 and further comprising the steps of:
providing a stud of aluminum comprising a flange and a threaded segment; and
coating the stud with a layer comprising tin and zinc and having an average thickness of 5 to 16 microns, and wherein the tin is between 60 and 80% by weight of the layer.
11. The method according to claim 7 , and further comprises, after the pre-treating step and before the tin-zinc coating step, a step of coating the nut with an inner layer comprising copper or zinc.
12. The method according to claim 11 , wherein the inner layer has a thickness between 200 nm and 3 microns.
13. A grounding assembly for clamping an eyelet of an electrical conductor, the grounding assembly comprising:
a stud of aluminum including a flange, a threaded segment, and a contact surface; and
a nut of aluminum including an internal thread and an outer plated coating comprising tin and zinc, wherein the tin is between 60% and 80% by weight of the outer plated coating and the outer plated coating has an average thickness of from 5 to 16 microns.
14. The grounding assembly according to claim 13 wherein the outer plated coating extends over the internal thread of the nut.
15. The grounding assembly according to claim 13 , and the nut further including an inner coating comprising copper or zinc, the inner coating having a thickness between 200 nm and 3 microns.
16. The grounding assembly according to claim 13 , wherein the zinc of the outer plated coating is between 20% and 40% by weight of the outer plated coating.
17. The grounding assembly according to claim 13 , wherein the stud is a weld stud and includes a weldable segment located on an end of the stud.
18. The grounding assembly according to claim 13 , wherein the stud includes a plated coating comprising tin and zinc, wherein the tin is between 60% and 80% by weight of a plated coating and the plated coating has an average thickness of from 5 to 16 microns.
19. A method of assembling a grounding assembly for clamping an eyelet of an electrical conductor into electrical contact with a workpiece, the method comprising the steps of
providing a stud of aluminum including a flange, a threaded segment, and a contact surface;
providing a nut of aluminum including an internal thread and an outer plated coating comprising tin and zinc, wherein the tin is between 60% and 80% by weight of the outer plated coating and the outer plated coating has an average thickness of from 5 to 16 microns;
threading the nut onto the stud to form a preassembly before welding;
welding the nut and stud preassembly to the workpiece;
unthreading the nut from the stud;
installing the eyelet over the stud; and then
rethreading the nut onto the stud and clamping the eyelet between the nut and the contact surface.