Cadmium Substitution - garteur

GARTEUR LIMITED
ANNEX A
Coatings and methods of coating application
A.1 Introduction
With the exception of the aluminium-magnesium coatings prepared by unbalanced
magnetron sputtering, all the coatings investigated were deposited using commercially
available processes. Table A1 identifies the various processes examined and the
companies where the coating was carried out. More detailed information concerning the
coating process schedules and standards is given in the subsequent sections of this
Annex.
A.2 Coating preparation
A.2.1
Electrodeposited zinc-cobalt-iron coatings
The zinc-cobalt -iron coatings were plated from a non-cyanide alkaline solution supplied
by Enthone OMI under the tradename Zincrolyte NCZ CF. The chemical composition of
the bath is given in table A2. Details of the plating schedule are given in table A3.
A.2.2
Electrodeposited zinc-nickel coatings
The electrodeposited zinc-nickel coatings were prepared using the CorroBan ® process.
The process was originally developed by Boeing and produces a coating containing
between 6 and 20% nickel. The composition of the electroplating bath employed is given
in table A4.
The pH of the bath was maintained in the range 6.1 to 6.3 and the bath temperature held
between 18 to 26 o C. The coating deposition rate is approximately 10µm in 30 minutes at
a cathode current density of 54 - 162 amps/m 2 .
Details of the standard process sequence are given in table A5.
a) Test panels
Steel test panels were plated to give a coating thickness of 15 to 20µm. Two sets
of panels were prepared, one set was left as-plated and the second set was
treated using the CorroBan ® passivation process.
b) Fatigue specimens
Fatigue specimens were prepared in accordance with the schedule given in table
A6.
A.2.3
SermeTel CR984/985
The SermeTel coatings were applied by Sermatech International Inc. Details of the
coating procedures employed are given in table A7.
GARTEUR SM/AG17 TP128 Page 39