STERLING
EP - Bright Silver Plating Process
EU 86253 |
| STERLING
EP is a decorative process for depositing bright silver over
a wide range of current densities. The easy maintenance gives
the advantage of having an economical bath operation. The
deposits are pure silver (not an alloy), have high electrical
conductivity, are very hard (about 110 HV; this means greater
wear resistance) and have an increased tarnish resistance.
|
| COMPOSITION
OF THE SOLUTION: |
| SERISSA
13 SILVER SALT - 250 Gms/l
POTASSIUM HYDROXIDE - 8. 0 Gms/l
EU
86254 STERLING EP Part A - 40-50 ml/l
EU 86255 STERLING EP Part B - 30 ml/l
Fill
a perfectly clean tank with 2/3 of deionized water. Add the
required amount of SERISA 13 SILVER SALT. Dissolve completely.
Filter on activated carbon. Add, while stirring, the STERLING
EP Part B and then the STERLING EP Part A. Allow to stand
for several hours or overnight.
|
| WORKING
CONDITIONS |
| Cathodic
Current Density |
- |
1
- 4 A/dm2 |
| Anodic
Current Density |
- |
1
- 4 A/dm2 |
| Temperature |
- |
20
- 25 °C |
| pH |
- |
11
- 12.5 |
| Anodes |
- |
Pure
Silver |
| Anode
hooks |
- |
Stainless
Steel |
| Anode
Bags |
- |
Nylon |
| Agitation |
- |
Cathodic |
| Filtration
|
-
|
Suggested |
| Tanks
|
-
|
Steel
lined with PVC |
| Cooling/Heating
coils |
- |
Stainless
Steel |
| |
|
|
|
| EFFECTS
OF THE ADDITIVES: |
| The
STERLING EP Part A is responsible for the degree of brightness
of the deposits; a lack of Part A gives hazy deposit at low
current densities. The
STERLING EP Part B acts as an auxiliary, helping and making
more uniform the effect of Agent A. Its concentration can
vary within wide limits.
|
| MAINTENANCE: |
The
consumption of the additives depends on the required degree
of brightness, on the drag-out and on the working current
density.
An average consumption rate for 1000 Amp/hr is:
EU 86254 STERLING EP Part A - 2 litres
EU 86255 STERLING EP Part B - 0.4 litres
|
| PLATING
SPEED: |
The
plating speed is 0.65 per min at 1 A/dm2. The maximum current
density depends on the type of movement, on the shape and
size of the parts to be plated, on the distance between anode
and cathode, on the concentration and temperature of the solution.
|
| CONTAMINANTS:
|
The
copper, with a normal concentration of “free” cyanide,
is not co-deposited in concentrations up to 2-3 g/l; with higher
concentrations it is possible to have dark deposits. The Nickel
is co-deposited with Silver, giving darker deposits. Lead and
Tin give rough and brittle deposits; they can be removed by
dummying the solution.
Organic contaminants give dull and streaked deposits and dark
stains at the low current densities.
These contaminants can be removed treating the solution with
activated carbon. This treatment partly removes the Brighteners
too.
|
| SAFETY
IN HANDLING AND USE |
Refer
to relevant Material Safety Data Sheets.
|
RONUK
AZ PROCESS