Method of inspecting a metal coating and a method for analytical control of a deposition electrolyte serving to deposit said metal coating
View Patent ↗For fast and secure determination of the quality of a metal coating as well as of an electrolyte for depositing a metal, in particular for electrolytic deposition of nickel such as of semi-gloss nickel and bright nickel and for analytical control of the deposition electrolyte, a method of inspecting a metal coating is provided, which involves the following method steps: a) depositing the metal coating from a deposition electrolyte onto a working electrode; b) electrolytically dissolving the metal coating through anodic polarization of the working electrode with respect to a counter electrode, which is in electrolytic contact with the working electrode; c) recording an electrical dissolution potential at the working electrode over time, said potential occurring during a dissolution of the metal coating; and d) determining a time-averaged vale of the dissolution potential.
1. A method of analytically monitoring a deposition electrolyte serving for depositing a metal coating, comprising the steps of:
a) depositing the metal coating from the deposition electrolyte onto a working electrode;
b) electrolytically dissolving the metal coating through anodic polarisation of the working electrode with respect to a counter electrode, which is in electrolytic contact with the working electrode;
c) recording an electrical dissolution potential at the working electrode over time, said potential occurring during dissolution of the metal coating;
d) determining a time-averaged value of the dissolution potential;
e) determining a difference between the time-averaged value of the dissolution potential and a reference value; and
f) allocating said difference to a difference between the concentration of a component of the deposition electrolyte determining the dissolution potential and a reference concentration.
2. The method of analytically monitoring a deposition electrolyte as set forth in claim 1 , wherein the metal coating is a constituent part of a multilayered metal coating system.
3. The method of analytically monitoring a deposition electrolyte as set forth in any one of the previous claims 1 - 2 , wherein, prior to performing method step b), the method further comprises:
b1) transferring the working electrode provided with the metal coating into an electrolysis cell containing a dissolution electrolyte and comprising the counter electrode.
4. The method of analytically monitoring a deposition electrolyte as set forth in claim 3 , wherein the dissolution electrolyte contains ions of the metal to be deposited as well as at least one acid.
5. The method of analytically monitoring a deposition electrolyte as set forth in any one of the previous claims 1 - 2 , wherein the electrolytic dissolution of the metal coating takes place under galvanostatic conditions.
6. The method of analytically monitoring a deposition electrolyte as set forth in any one of the previous claims 1 - 2 , wherein the working electrode is a rotating platinum electrode.
7. The method of analytically monitoring a deposition electrolyte as set forth in any one of the previous claims 1 - 2 , wherein the metal coating is an electrolytically deposited nickel coating.
8. The method of analytically monitoring a deposition electrolyte as set forth in any one of the previous claims 1 - 2 , wherein the metal coating is an electrolytically deposited semi-gloss nickel coating or an electrolytically deposited bright nickel coating.
9. The method of analytically monitoring a deposition electrolyte as set forth in any one of the previous claims 1 - 2 , wherein values of the dissolution potential at the working electrode are determined within an imposed time interval and that the values obtained are averaged in order to determine the time-averaged value of the dissolution potential.
10. The method of analytically monitoring a deposition electrolyte as set forth in any one of the previous claims 1 - 2 , wherein the deposition electrolyte originates from a coating tank and is transferred continuously to the working electrode.