Where the
world gathers for metal finishing
Q&As since 1989


-----

Nickel-Chromium Plating Thickness Issue on Non-Alloy Steel Rod

Hello,

We are making products from wire. We are using non-alloy steel wire with diameter 10,83 ± 0,03 mm. For Ni-Cr coating we have next demands: minimum 25 µm of Ni and minimum 0,4 µm of Cr. After Ni-Cr coating must wire have diameter 11 -0,5/-0,15. Now we have some problems: on ends of wire we can't get diameter 11 -0,5/-0,15 (diameter is bigger), we can't appropriately reduce coating thickness round entire surface (rim) of wire (on the part of surface which is closer to anode we have bigger thickness of coating) and we would like to know which measurement device can measure coating thicknesses bigger than 25 µm (now we have X-ray device which can measure 20 ± 5 um).

Thanks for your answers and best regards.

Janez Hocevar
product designer - Novo mesto, Slovenia
October 1, 2008

Assuming that the wire is very nearly round and is uniform in dimension (you need to prove this) the solution to your problem is to use either shields or robbers to reduce the plating thickness on the ends. If you are getting too much plating on the side of the rod, increase your agitation and move the parts further away from the anode. Also take a look at what affect temperature has on distribution.

James Watts
- Navarre, Florida
October 2, 2008