| RONUK
AZ PROCESS - Chloride Base |
|
|
| OPERATING
INSTRUCTIONS |
| RONUK
AZ: is a bright chloride zinc plating process.
This
process is designed to produce bright deposit over wide
current density ranges and with high cathode efficiency.
|
| ADVANTAGES |
Excellent
Brilliance, Tolerance to Iron, Tolerance to higher temperatures,
Accepts Passivation easily, Low cost neutralization &
Waste Disposal, Contains no Cyanide.
|
| MAKE
UP |
| a. |
Perfectly
clean the tank with a solution of Hydrochloric acid
(5%) as also the Filter Unit. |
| b. |
Empty
and rinse out the tank with tap water as also filter
unit. |
| c. |
Fill
the tank at 2/3rd volume with water to 500C. |
| d. |
Add
the required quantity of Salt B (approximately 225 gms/lit)
with vigorous mixing till the salts gets totally dissolved. |
| e. |
Add
the required quantity of Salt A (approximately 100 –
120 ml/lit) shake & mix strongly till it get totally
dissolved. |
| f. |
See
that the solution is continuously filtered after make
up. |
| g. |
Add
40 ml/l of AZ:M
0.4 – 1 ml/l of AZ:R. |
| h. |
Make
up to the final volume with the water and maintain filtration.
Water used should be preferably demineralized. |
| |
|
|
| BATH
MAINTENANCE |
| Parameters |
Barrel
& Rack |
| |
Range
|
Optimum |
| Zinc
Metal |
g/l |
25
– 40 |
30 |
| Total
Chloride |
g/l |
110
– 150 |
135 |
| Boric
Acid |
g/l |
20
- 30 |
35 |
| AZM
|
ml/l
|
30
– 50 |
40 |
| AZR
|
ml/l
|
0.4
– 1.0 |
0.5 |
| CONSUMPTION
UNDER NORMAL OPERATING CONDITIONS/1000 AMP HR |
| AZ:
M |
150
– 200 Ml |
|
|
| AZ:
R |
100
– 150 Ml |
|
|
| Bath
should be preferably used at optimum levels. Additions
of M & R will vary as per plant configurations maintenance
of chemicals, ingression of metallic & organic impurities
etc. |
| |
|
| OPERATING
PARAMETERS: (RACK & BARREL) |
| Parameters |
Range |
Optimum |
| pH
|
4.8
– 5.2 |
4.8 |
| Temperature
|
20
to 45°C |
30°C |
| Cathode
Current Densities |
1
to 5 Amp /dm2 |
|
| Anode
Current Density |
2
to 3 Amp /dm2 |
|
Voltage
|
5
to 9 (Barrel)
2 to 4 (Vat) |
|
| Filtration
|
Continuous |
|
| Agitation
|
Air
Agitation |
|
| Anode
|
Pure
Zinc 99.99% |
|
| Cooling
|
Necessary
for Automatic Plants. |
|
| |
|
|
|
| CONTROL
OF BATH CONSTITUENTS: |
| *
Zinc |
: |
Control
by analysis. |
| *
Total Chloride |
: |
Control
by analysis. |
| *
Boric acid |
: |
Control
by analysis. |
| *
pH |
: |
PH
meter is used as per the preference. PH paper though
calibrated against a ph meter can be used. |
| |
|
|
|
| EQUIPMENT: |
| |
| Tank |
| Polypropylene
or PVC lined. |
| Anodes |
| 99.9%
purity, in slabs or rods, or pellets contained
in titanium
baskets. |
| Anode
Baskets |
| It
is recommended to maintain the titanium anode baskets full
with zinc and not apply greater than 9 volts, otherwise there
is a risk of dissolving the titanium. If required the anodes
or baskets should be protected
by polypropylene bags. |
| Agitation |
| Air
agitation is highly recommended when plating in rack. Otherwise
mechanical agitation must be used, to make necessary renewal
of cathodic film. Solution, which is mechanically agitated,
may easily be converted to air agitation. |
| Filtration |
| The
filtration rate should be atleast one/two bath volume/hour. |
| |
| TROUBLE
SHOOTING: |
| Poor
Throwing Power & lack of coverage. |
-
Zinc content high / Low
Chloride
- High current
- Low boric acid
- pH too high or too
low
- Lack of AZ: M
- Imperfect preparation
of
items
|
Adjust
Zinc, Chloride or increase the anodic surface.
Reduce the current.
Add boric acid
Adjust the pH
Add AZ:M
Correct
the deficiencies of preparation.
|
| Deposition
becomes dull or black when dipped in 0.5% nitric acid
or blue passivation solution. |
-
Strong metallic contamination |
Treat
with 1 to 2 gm/Ronuk Zinc Copper Chrome Remover/ZCCR.
After one hour vigorous agitation, filter to remove
ZCCR. Alternatively plate out the solution at 0.2 to
0.5 Amp / dm2. |
| Rough
deposit |
-
Suspended matter
- pH too high
|
Check
the filter pump/filter the solution.
Reduce the pH to recommended value.
|
| Pitting
or barrel marks |
-
Too high current
- Iron contamination
- Low barrel speed
- Barrel perforation
too small
|
Reduce
current to barrel
Treat the solution
by H2O2 (0.1 to 0.2 ml/l).
Increase the barrel speed to 10 – 12 rpm.
Use barrel with larger performation.
|
| Discoloration
or staining on Passivation |
-
Insufficient swilling between
Plating & Passivation
-
Iron, Copper or Chrome
Contamination
|
Ensure
effective swilling & increase rinse tanks or increase
water inflow/outflow speed.
Treat the solution
by ZCCR treatment.
|
| Poor
LCD/dark at ZCD. |
Metallic/Organic
contamination
Or
High Metal Content
|
Add
CZ515C 2/5 ml/l to improve LCD or also add per shift.
Adjust Metal by dilution followed by addition of C2515B
to correct values. Add brightner M & R as per dilution.
|
| Higher
temperatures than the optimum |
Poor
LCD & breakdown of brighteners. |
Add
CZ TS when temperature reaches 38/400C. |
|
| |
| PRECAUTIONS
TO BE TAKEN |
| 1.
|
Maintain
the closed packing hermetically. |
| 2. |
Store in a cool and dry place. |
| 3. |
Use: glasses, gloves and protective cloths. |
| 4. |
Avoid all the contact with the skin and eyes: wash it
thoroughly in case of any contact. |
| 5. |
Avoid inhalation. |
|
RONUK
AZ PROCESS