Zinc & Zinc Alloys
ALKALINE NON CYANIDE ZINC-IRON PROCESS
FEZINK 206 is an alkaline zinc-iron electroplating process with good metal distribution properties, which adds to the traditional qualities of the FEZINK process the anti-corrosion properties and yellow and black finish requirements demanded by the automotive sector. In excess of 200 hours salt spray after thermal shock (1 hour at 120°C).
- Fill the tank one third full with water, preferably Dl water.
- Add the required amount of sodium hydroxide bit-by-bit with vigorous mixing (the reaction is highly exothermic; ensure the tank lining can withstand the temperature reached).
- Dissolve the zinc metal required.
- Allow solution to cool to 30°C.
- Add FEZINK Purifier 0.5 – 1.0 ml/l
- Give Dummy to the solution for few hours.
- Add FEZINK Brightner at the rate of 8 – 10 ml/l
- Put the solution under continuous filtration.
- Add FEZINK 206 Complex at the rate of 75 ml/l.
- Add FEZINK 206 Iron Additive at the rate of 3.5 ml/l.
- Put the solution under continuous filtration for at least 4 – 6 hours.
|For Rack & Barrel||Range||Optimum|
|110 – 130 g/l||120 g/l|
Zinc Metal (99.99 purity)
|9 – 10 g/l||11 g/l|
|50 – 120 ppm||70 ppm|
FEZINK 206 Complex
|70 – 80 ml/l||75 ml/l|
|FEZINK 206 Purifier||0.5 – 1.0 ml/l|
|FEZINK 206 Brightner||8 – 12 ml/l||10 ml/l|
|24 – 27ºC||24 – 27ºC|
Cathode current density
|0.5 – 1.0 A/dm2||1 – 3 A/dm2|
|10 – 20 Volt||70 ppm|
Current loading A/litr 0.7 maximum
Replenishment per 10000 AHr (both rack and barrel)
FEZINK 206 Purifier – 2 litres FEZINK 206 Purifier per 50 kg of Sodium Hydroxide added
or 0.4 ml/l at each line start-up
FEZINK 206 Brightner – 1 – 2 litres
FEZINK 206 Complex – 6 litres per 8 kg Sodium Hydroxide added
FEZINK 206 Iron Additive – 0.5 – 2 litres
Controls over Bath Constituents
Sodium Hydroxide consumed through drag – out. Control through analysis
Zinc Metal Control through analysis
This concentration of zinc should be controlled by use of an appropriate ratio of soluble anode
(zinc) surface and insoluble anode (mild steel) surface. During period of no production, zinc in
contact with steel baskets dissolves and concentration in the bath increases, this dissolution
rate increases with concentration of sodium hydroxide. It is therefore essential to remove the
soluble anodes from the tank during stoppage period.
In large volume installation, this requirement may be avoided by the following method:
The working tank is equipped only with insoluble steel anodes, the necessary zinc dissolution to maintain electrolyte equilibrium is carried out in an auxiliary tank, connected to the working tank.
FEZINK 206 Brightner
This brings brightness to the deposit. It need not be used if appearance requirements are not critical.
FEZINK 206 Purifier
This precipitates out metallic impurities which are inevitable in any treatment line. An excess is not harmful, but can turn the solution slightly cloudy. In this case, an addition of up to 5 ml/l bleach is required to produce a clear solution. Where the deposit at low cathode current densities is black, an addition of 2 – 4 ml/l FEZINK 206 Purifier will, in the majority of cases, cure this problem.
FEZINK 206 Complex
This maintains iron in solution and prevents its precipitation.
FEZINK 206 Iron Additive
This additive contains iron. An addition of 0.35 ml/l increases the iron content of the bath by 10 ppm.
All equipment must be thoroughly cleaned prior to use.
- Tank: Mild Steel or suitably lined.
- Anodes: It is recommended to use insoluble mild steel anodes of 3 -4 mm thickness to obtain a 1:1 anode / cathode ratio. The metal concentration in solution is maintained through the dissolution of zinc balls, bars, ovals or plate anodes (99.99% pure)
contained in iron baskets. Dissolution is encouraged if the steel surface area in contact with zinc is as large as possible (sand blast or shot blast steel).
- Agitation: Mechanical agitation is recommended. Air agitation is not desirable.
- Filtration: Continuous at the rate of 1-2 tank turn overs per hour. Use Plate or cartridge filter of porosity 10µm optimal filtration is necessary to obtain full brightness; presence of suspended particles will lead to mat deposit and risk of blistering.
- Extraction: Desirable
- Heating and Cooling: Steel or titanium (24 – 40°C).
The quality of deposit obtained depends upon the proposed pre-treatment sequence. Use on non-ionic surfactants is highly recommended throughout preparation sequence.
For steel, following sequence is recommended.
1. Immersion clean
2. Water rinse
4. Water Rinse
5. Electro – clean
6. Water Rinse
8. Water Rinse
9. Static Rinse prior to zinc plate
10. Zinc plate
11. Water rinse
12. TRIBLAK Passivation
13. Water rinse
HEALTH & SAFETY:
Keep containers tightly closed when not in use. Store in dry place and protect from dust. Wear eye/face protection, gloves and protective clothing. Avoid contact with eye and skin, in case of contact, wash with fresh water, and avoid breathing fumes, mist or sprays.
Mix vigorously and reduce the pH to 9.00 with dilute acid. Filter out or clarify and decant off the precipice zinc. Adjust the pH of the filtrate according to local pollution control regulation before discharge.
Our recommendations are made in good faith and are based on our skill and experience. As conditions of use are normally not in our control nor ideal. Ronuk does not give any guarantee or warrantee explicit or implicit and we are not liable to any person or corporate by reason thereof.
ALKALINE NON – CYANIDE ZINC PROCESS
This plating solution is entirely free from cyanide and hence Hazard free. The solution is Easy to treat for Effluents. This is suitable for Barrel Plating and it can also be used for Rack Plating. The rate of Deposition on Zinc is fairly comparable to that of other Zinc solutions. The plated surface takes all types of passivations.
Equipment used for Cyanide Zinc Plating is good enough for this solution. However, the following requirements need to be met.
- Mild air agitation or Cathode movement
- Continuous Filtration through correctly sized filter as per Tank size volume. It is important to remove
floating contaminants by operating the filter in conjunction with a weir.
- Steel or polypropylene tanks are preferred. The auxiliary tank must be constructed
Usual Anodes used for Cyanide Zinc Plating can be used. The Solution being a Zincate type with Extra Caustic, it affects the Dissolution of Anodes at a higher rate. To obviate this, it is necessary to use plain M.S. Plate or expanded mesh as anodes along with Zinc anodes. The Ratio of Zinc Anodes to M.S. Anodes should be as follows:
- For Rack Plating: – 30-40% Zinc Anodes Rest M.S. Plate Anodes.
- For Barrel Plating: – 50% Zinc Anodes Rest Mild Steel Plate Anodes.
The solution needs a Critical control on the maintenance of the Ratio of Zinc and caustic
contents in the plating solution. When this Ratio is disturbed the solution fails to give standard performance.
Normal maintenance standards are as follows: -
|STANDARD||10.0 g/l||100 g/l|
|RANGE||10 – 15 g/l||100 -150 g/l|
Plating solutions for Barrel and Rack have same concentrations.
- Plating solution does not have as great a tolerance to impurities like cyanide solution.
- Plating solutions when made fresh need to add NCZ Purizinc 0.5 – 1.0 ml/l for a longer trouble free performance.
- Few Hours low current dummy treatment.
- After dummy treatment filter the solution.
- Regular analysis of solution to maintain standards, send solutions to our laboratory.
SOLUTION MAKE UP
Method I: Least expensive, more time consuming.
- Provide for ventilating the tank.
- Add cold water to about 50% of the working volume of the tank.
- Add a good grade of sodium hydroxide to the tank. Use about 130 g/l based on the working volume of the tank. The tank will get hot and choking caustic fumes will evolve if ventilation is not provided.
- Place as many steel baskets of zinc balls into the tank as are available. The dissolving process of zinc requires intimate contact with steel to complete a galvanic couple.
- Keep the tank above about 32ºC. The dissolving process is very slow in a cold solution. Allow the solution to work for about 16 to 24 hours or until the zinc concentration (based on the working volume of the tank) is about 11.3 g/l.
- When all the additions have been made the solution should be well agitated and then electrolysed for up to 24 hours at 2 A.S. D. before use.
- In the following order add the required quantities of sodium carbonate, NCZ purizinc, NCZ B 555 brightner, NCZ Booster.
Method II: More costly, easier, safer and faster.
- Fill up the tank to half its volume with cold water.
- Add requisite quantity of NCZ B 555 Salt (L).
- mixed it properly.
- Add the rest of water to make up to almost the tank volume (A little less than required)
- Add NCZ Purizinc – 0.5 – 1.0 ml/l before adding Brighteners Re-adjust the plating solution level to its correct volume with Demineralized soft water.
- Continuous Filtration is recommended.
For Barrel & Rack
NCZ B 555 Salt (L) – dilution 1 litre to 3 litre.
- Zinc : 10 – 15 g/l
- Caustic Soda : 100 – 150 g/l
However Zinc to Caustic Ratio MUST be maintained at Zinc: Caustic – 1: 10.
Current Densities: -
For Barrel : 10 to 20 amp/sq ft.
For Racks : 20 to 40 amp/sq. ft
Both these solution at higher concentrations are capable of giving deposition rates comparable to Cyanide Solution.
RONUK NCZ B 555 BRIGHTNER & NCZ BOOSTER to be added to as hereunder.
- Barrel Solution is: – 12/15 ml/l of NCZ B 555 Brightner
- Rack Solution is: – 15/20 ml/l of NCZ B 555 Brightner.
- NCZ Booster - 1- 2 ml/l for both Barrel & Rack.
This solution is run at Room Temperature i.e. 24-28ºC. However it can run safely up to 35/40º C.
For Barrel: 200-300 ml Brightner per 1000 amp hours.
For Rack: 275-375 ml Brightner per 1000 amp hours.
NCZ Booster: 50 – 100 ml per 1000 amp hours for both barrel & rack.
The plating procedure would be as follows:
- Hot soak cleaning at 80/85º C for 5 minutes.
- Anodic cleaning at 70/75ºC, 10/12 Volts for 3-4 min. (This step is absolutely essential for good plating performance)
- 50% (v/v) Hydrochloric Acid Dip
- 1-2% (w/v) Caustic Soda dip
- NCZ B 555 Process
- 0.5% – 1%(v/v) Nitric Acid Dip
- Air Drying
- Give carbon treatment to remove trace of Brightener and Filter
- Add Dilute Hydrochloric Acid to adjust pH to 8.0 to precipitation Zinc Metal & Filter.
- Re-adjust the pH.
Our recommendations are made in good faith and are based on our skill and experience. As conditions of use are normally not in our control nor ideal. Ronuk does not give any guarantee or warrantee explicit or implicit and we are not liable to any person or corporate by reason thereof
ACID ZINC PROCESS
CLZ:219 Acid Zinc Process is a 2 pack /two component Chloride Zinc Process and can be used to plate on Carbo-Nitrided, Carburised case hardened steel of cast and malleable iron and mild steel.
ADVANTAGES OF THE PROCESS:
- Excellent Brilliance
- Fast Brightening Action
- Excellent Ductility
- Contains No Cyanide
- Excellent Throwing Power
- Plates directly on all bases metals
- Tolerance to Iron
- Increased production rates operating with 98/100 % efficiency
- Accepts passivation easily.
- Low cost Neutralization and waste disposal.
- Low or no Boric Baths for certain application. May be used with Ronuk Liquid Acid
- Zinc salts.
SOLUTION COMPOSITION FOR VAT (make up)
- CZ: 515 A : 120-150 ml/l
- CZ: 515 B : 250-300 gm/l
- CLZ: 219 A : 30 -40 ml/l
- CLZ: 219 B : 0.5 – 0.8 ml/l
FOR BARREL (make up)
- CZ: 515 A : 100 – 110 m/litre
- CZ: 515 B : 200 – 225 gm/l
- CLZ: 219 A : 30 – 40 ml/l
- CLZ: 219 B : 0.5 – 0.8 ml/l
- Continuous Filtration
- High grade pure Zinc Anodes in Polypropylene Bags.
- Mild Air Agitation or Cathodes Rod movement
- PVC lined Tank
- Temp. between 25 and 40 degree C.
- Current Density for Rack, Max 40 amp/sq ft. at 3 volts.
- For Barrels 8/15 amp/sq ft. at 6/8 volts.
- For small Barrels 8/10 amp/sq ft. at 4/6 volts.
- pH between 4.8-5.4. For adjustment either LR Grade Hydrochloric Acid LR Grade
- Potassium Hydroxide to be used. Preferably use Laboratory Grade or Ronuk materials
- for adjustment
Both CLZ: 219 A & B are used for both make up and maintenance.
- CLZ: 219 A : For 1000 amp hrs – 150-250 ml/1000 amp hrs.
- CLZ: 219 B : For 1000 amp hrs – 100-150 ml /1000 amp hrs.
All maintenance additions are based on approximations and will depend on plants configurations, chemical constituents of bath, impurities, drag out and other factors beyond our control.
Ronuk has both Hexavalent & Trivalent passivations for yellow and blue. Ronuk sealers for higher corrosion resistance may be also considered. Zinc iron plating can be considered with trivalent black passivated.
- RECOMMENED PROCESS CYCLE
- Hot Soak Clean
- Water Rinse
- Anodic Clean (50/100 amps/sq ft.)
- Water Rinse
- 50% HCL Dip
- Water Rinse
- Second Water Rinse
- Zinc Plating
- Water Rinse
- Second Water Rinse
- Water Rinse
- Warm Water Rinse and Dry
RATE OF DEPOSITION- AVERAGE:
For 10 Microns
For 0.001 Inch
2 A/dm2 : 18.5 mins
20 A/sq. ft : 43.6 mins
3 A/dm2 : 12.3 mins
30 A/sq.ft. : 29.1 mins
4 A/dm2 : 9.3 mins
40 A/sq. ft. : 21.2 mins
For 5 Microns
For 0.00025 Inch
0.2A/ dm2 : 93 mins
2 A/sq. ft. : 108 mins
0.5A/dm2 : 38 mins
5 A/sq. ft. : 44 mins
FOR SPECIAL ANALYTICAL CONTROL:
- FOR VAT
1) Zinc Metal : 35-45 gm/ltr
2) Total Chloride (as Chloride ion) : 130 – 160 gm/ltr
3) Boric Acid : 30-35 gm/ltr
- FOR BARREL
1) Zinc Metal : 30 – 35 gm/ltr
2) Total Chloride (as Chloride ion) : 100 – 130 gm/ltr
3) Boric Acid : 20 – 25 gm/ltr
- Ronuk Zinc Copper Chrome Remover, 3 gm Per ltr of CZ 515 A is to be added as hereunder.
- First take Zinc Copper Chrome Remover Powder 3 gm in 300 ml of water and add there to
- Hydrochloric Acid – 0.5 ml.
- Shake well; allow the power to settle at the bottom.
- Decant the solution and again second time put water, shakes well, allow the powder to settle
- and decant the solution.
- Repeat the washing process further three times and i.e. a total of 5/6 times only then use this
- activated powder for 1 ltr. Of CZ 515 A solution. Give agitation to the solution.
- This CZ 515 A solution is now ready to use for the Acid Zinc Bath.
1. CZ: 515 A 100 ml/l 150 ml/l
2. CZ: 515 B 225 gm/l 250 gm/l
Mix well and make up to volume
1) CLZ: 219 A – 30 – 35 ml/l
2) CLZ: 219 B – 0.5 – 1.0 ml/l
Run the Barrel/Vat by plating Junk items for first 2/3 lot. Then check solution is clear impurities at low current density.
Add requisite quantities of A & B every 1000 amp/hrs.
- Solution to be allowed to cool during filtration.
- Attach Dummy to check whether any deposition of metallic impurities.
- Clear filter Unit on or obtaining clear Dummy and wash filter cloth.
- Put new papers in the Filter Unit.
- Make additions of the requisite quantity of CLZ 219 A additive
- Check purity of Anodes they should be 99.9% pure
- Do not plate at too high a voltage
- Cathodes to Anodes ratio should be 1: 2
- Anode area should be twice the Cathode area
Our recommendations are made in good faith and are based on our skill and experience. As conditions of use are normally not in our control nor ideal, Ronuk does not give any guarantee or warrantee explit or implicit and we are not liable to any person or corporate by reason thereof.