Conversion Coatings

KEMSEAL 23 RG

KEMSEAL 23 RG
SEALENT FOR PASSIVATED ZINC & ZINC ALLOY

INTRODUCTION:

The KEMSEAL 23 RG sealant is applied by simple immersion after passivation and forms a thin film on the surface, with good resistance to corrosion. KEMSEAL 23RG films have good tolerance to thermal shock without significant loss of corrosion resistance.

Appearance is transparent when applied over a blue or colorless trivalent passivates.

The process is non-toxic and can easily be installed as the final stage on any plating line.

EQUIPMENT REQUIRED:

Tanks: Steel tanks lined with PVC are suitable. Tanks may also be fabricated from polypropylene or polythene. Stainless steel may also be used.

Coils: Stainless steel.

Agitation: Mild mechanical agitation.

OPERATING CONDITIONS:

  OPTIMUM RANGE

KEMSEAL 23 RG

200 ml/l  120 – 300 ml/l

pH

10.0 9.7-11.0

Temperature

55ºC  50-60ºC

Immersion Time

90 Sec 60-150 Sec
Drying Temperature 80ºC 70-120ºC
Drying Time 10 min  5-20 min 
MAKE UP PROCEDURE:

Fill the tank to three quarters of final volume with water, add required amount of KEMSEAL 23RG and mix well. Top up to the final volume and continue mixing. Heat to operating temperature. Check pH and correct if necessary using dilute sodium hydroxide.

The solution is now ready for use.

OPERATION

KEMSEAL 23 RG solution forms the final stage of the plating sequence and may be added, for example to the final rinse tank. Do not rinses after application of KEMSEAL 23 RG. After treatment. parts should enter the drying stage in the normal manner. Small parts may be spin-dried.

CONTROL PROCEDURE / pH CONTROL:

Maintenance of the process may be accomplished by adjusting the pH of the solution regularly by small additions of KEMSEAL 23RG, diluted sodium hydroxide or diluted acetic acid.

Too low pH results in non-uniform appearance and decreased resistance to neutral salt spray.

ANALYTICAL METHODS:

The analysis is based on the determination of the solids content.

Weigh a clean aluminum dish or watch glass (We). Add 10 ml KEMSEAL 23RG bath solution and re-weigh (Wa). Stove in the oven for two hours at 120°C. Cool and re-weigh (Wb).

Calculate the content of KEMSEAL 23RG:

Wb – We

ml/l of KEMSEAL 23RG     = —————————- x 4650

                                             Wa – We

Correct the bath if necessary with KEMSEAL 23RG

CAUTION:

The KEMSEAL 23RG concentrate is a slight irritant. Avoid contact with skin and eyes. Wear protective clothing and safety goggles. Flush exposed areas immediately with clean cold water. In case of injury or eye contact call a doctor.

HANDLING AND SAFETY INSTRUCTIONS:

For detailed information consult the material safety data sheets for this product. Please read material safety data sheets carefully before using this product.

Note:

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.

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LEHRAL-ZN-2

LEHRAL-ZN-2
BRONZE TO GOLDEN YELLOW

The solution prepared with Lehral-Zn-2 Concentrate can be employed for imparting an attractive bronze film on zinc surface including die castings; High resistance to the formation of white corrosion is obtained.

Concentration:

For Acid Zinc : Lehrul-Zn-2                    -           25 – 45 ml
                                                Water                            -           1 litre

For Cyanide Zinc           :           Lehrul-Zn-2                    -           8- 25 ml
Water                            -           1 litre

Operating Conditions:

Temperature                  -           21ºC – 32ºC                                                                               Treating time                 -            5 – 20 Secs.

Operation:

The periods of immersion and temperature depend upon the shade of colour desired in the film and the corrosion resistance required. A few trials should be carried out to determine the correct concentration and operating conditions for the user’s particular application.

Maintenance:

At the close of a working day, the level of the operational solution is brought up to its working level by adding water. Lehral-Zn-2 concentrate is then added at the same concentration as used for the bath makeup. The pH is adjusted either with nitric acid or with sulphuric acid but preferably with Lehral-Zn-2 pH maintenance concentrate.

SURFACE CONVERSION COATING FOR ZINC AND CADMIUM BY LEHRAL:

From transparent or brilliant through iridescent yellow-red to olive drab and black shades can be imparted to zinc or cadmium surfaces; individual parts may be treated more or more or less manually or continuous lines or wires; strips or plates may be treated in automatic plants. Small components may be treated in dipping baskets or in barrels. Where non reflective surface are required, olive drab or black shades may be given. All the operations are simple but systematic working and care are necessary at every step. It is important to ensure that the carry over from one solution into another does not reduce the working life of the solution. A majority of the troubles in surface conversion Treatments can be traced to incomplete or improper rinsing or swilling. When plated surface are treated, one single factor of importance is the proper maintenance of the plating solution. For example, if the zinc bath is contaminated with copper, the recessed and low current density areas of the components will be darkened. This phenomenon is in fact used for deducting the presence of copper contamination in zinc solutions. The removal of the metal during conversion treatment depends upon the composition and the type of the conversion solution. It is however, advisable to assume that some thing like 0.001 mm (1 micron) of the metal may be removed in about 30 seconds of immersion. It is, therefore, necessary that the minimum thickness of zinc or cadmium plate will be 0.005 mm or 5 microns. Preferably 7.5 microns should be deposited. Same bath should not be used both for zinc and cadmium.

Flow of Operations:

Whereas plated surface after thorough swilling can be transferred directly to a surface conversion solution, zinc based die castings require to be degreased and activated.

Plated Surfaces:

If the colour in the film is acceptable, the sequence of operations will run as follow:

  1. Zinc or Cadmium plate.
  2. Rinse – warm or cold running water.
  3. Neutralization in 0.25% to 2% acid dip preferably made up with the same acid that is used in the makeup of the solution.
  4. Optional cold rinse.
  5. Treatment in Lehral solution.
  6. Rinse – preferably cold running water.
  7. Hot rinse, temperature not exceeding 65ºC
  8. Dry in a centrifugal drier or steam of warm air.

Several rinse operations can be dispensed with by the use of a single spray rinse. It is then necessary to have available a continuous supply of water. Some operations are followed where colourless coatings are obtained in a single step. Where coatings are to be dyed or colourless and transparent coatings are to be obtained in two steps, the following sequence of operation may be followed:

  1. Zinc or Cadmium plate.
  2. Rinse – warm or cold running water.
  3. Neutralization in an acid dip preferably made up with the same acid that is used in the make up of the solution.
  4. Optional cold rinse.
  5. Treatment in Lehral solution.
  6. Rinse – preferably cold running water.
  7. Second step treatment for removal of colour. Alternatively dye the surface.
  8. Rinse – warm or cold running water.
  9. Hot water rinse.
  10. Dry in centrifuge or a warm blast of air.
Zinc based Die-Castings:

If a brilliant surface is desired, the work may be buffed in the manner or may be put through a dry dipping or a polishing solution. For a Superior finish it may even be zinc plated to a minimum thickness of 5 microns to7.5 microns. Where high finish is not required, the work is degreased and the surface activated by an immersion in a 5% formic acid or 1% to 2% sulphuric or phosphoric acid dip. The sequence of operations would flow as follows:

  1. Degrease.
  2. Rinse – in cold or warm water.
  3. Acid dip in 5% formic acid 1 to 2% sulphuric or phosphoric solution. Alternatively – if a brilliant finish is required, the work is put through Ronuk Zinc Chemical Polishing solution. Treatment in the solution also helps in deburring of a component.
  4. Rinse – preferably cold running water.
  5. Treatment in one of the Lehral solutions.
DISCLAIMER:-

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.

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OLIVE DRAB

OLIVE DRAB
SSINGLE CHROMATE PASSIVATION

The olive drab chromate passivation coating given maximum corrosion resistance to zinc and cadmium deposits and provides a sound key for subsequent painting. On bright zinc a true olive drab colour is obtained and on cadmium, the colour varies from pale green to dark khaki depending upon the immersion time. The process may be applied directly to zinc base die casting in addition to electrodeposited zinc and cadmium coating.

Equipment:

Moulded polyethene or polypropylene tank.

Solution Composition:

OLIVE DRAB OD SINGLE          :           80 – 100 ml/ litre

Half fill the tank with cold water and add the required volume of Olive Drab OD Single. Make up to volume with cold water and stir thoroughly.

Operating conditions:

Temperature                             :           28 – 32°C
Time                                         :           2 – 20 minutes.
Agitation                                   :           Slight mechanical movement.

Process Sequence

1. Bright zinc or cadmium plate to a minimum thickness of 8 to 10 microns. The percentage loss of zinc or
cadmium is 0.5 to 0.75 microns in 20 minutes immersion.
2. Thoroughly swill in cold running water.
3. Immerse in Olive Drab OD Single
4. Thoroughly swill in cold running water.
5. Dry in warm air or centrifuge, after blowing off excess water with compressed air. Do not dry with hot water as this will dull the passivated film.

DISCLAIMER:-

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.

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TOP SEAL

TOP SEAL
SEALENT FOR PASSIVATED ZINC & ZINC ALLOY

Ronuk Top Seal is a process designed for application to zinc plated and passivated pieces,

to remove their corrosion resistance.

EQUIPMENT:

The olive drab chromate passivation coating given maximum corrosion resistance to zinc and cadmium deposits and provides a sound key for subsequent painting. On bright zinc a true olive drab colour is obtained and on cadmium, the colour varies from pale green to dark khaki depending upon the immersion time. The process may be applied directly to zinc base die casting in addition to electrodeposited zinc and cadmium coating.

Equipment:

Tanks                                     :               Polypropylene or PVC
Heaters                                  :               Electrical heaters should be of glass

OPERATING CONDITIONS:

Parameters
Concentration                      :               10 – 15 %( v/v) made up in warm water
pH                                           :               11.0 – 11.2
Temperature                        :               30-50º C
Time                                       :               15 – 60 secs.
Bath should be filtered using a cartridge filter of 10-30 µm porosity.

pH

Measure the p-H of the working solution using a pH meter or close range pH papers. The pH should be maintained in the range 11.0 – 11.2.

Replenishment

It is recommended to replenish the bath with Ronuk Top Seal at the rate of 20 – 25 ml per square metre.

EFFLUENT

The Ronuk Top Seal bath will come to contain trivalent, Hexavalent and Zinc metal, which must be treated prior to discharge, to conform to all local and national regulations.

HEALTH AND SAFTY

The material is alkaline. Take all normal precautions when handling this type of product (gloves, safety glasses, and boots)

SHELF LIFE

One year from date of manufacture.

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.

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TRI BLUE 556

TRI BLUE 556
Trivalent Bright Blue Passivation for zinc

TRI BLUE 556 is trivalent chromium based process; designed to give a bright, pale blue finish to electroplated zinc surfaces.  The process is suitable for use on zinc deposits from all common
electrolytes.TRI BLUE 556 is supplied as a highly concentrated liquid of density 1.31 +/- 0.020
& is ecofriendly.

IMPORTANT NOTE:

Before using the product, please ensure that this complete document and relevant Health & Safety sheets have been read and understood.

MAKE–UP:

PARAMETER

ALKALINE ZINC/CYANIDE ZINC

ACID ZINC

Concentration 

10 – 15 ml/l

15-25 ml/l

pH

1.6 – 2.0

1.8 – 2.2

Immersion time

30 – 50 seconds

30 – 50 seconds

Agitation

Air Agitation

Air Agitation

Temperature

27oC – 32oC

27oC – 38oC

The precise concentration will be dependent on the desired appearance and individual plant characteristics and shall vary from component to component, type of plating and plant configuration.

Fill the tank approximately three- quarters full with main water and add the required amount of TRI BLUE 556 solution with mixing.  Make up to the operating level and temperature and again remix.

EQUIPMENT:

In existing installations, tanks already in use for blue passivation can be used for TRI BLUE 556.  These tanks should preferably be constructed from reinforced plastic materials.  Mild steel tanks lined with a suitable acid resistant material (for example glass fibre) are also not suitable.

Good solution mixing in rack application requires compressed air agitation.  The tube should be preferably be made from PVC and air throughput control should be fitted with oil free filters.

OPERATING CONDITIONS:
Concentration:

It is advised to operate at the lower end of the concentration band, using extended process times to compensate, where cycle time constraints allow, alternatively for automatic lines concentration can be elevated

Temperature:

At temperature below 15oC, passivation is slow and uneven, with spot formation and a matt
appearance.

pH:

To lower the pH, use additions of nitric acid.
To increase the pH, use additions of sodium hydroxide solution.

Immersion Time:

The immersion times quoted   above include the transfer time to the first rinse, as the solution
carried out on the work continues to operate during such a transfer.

Agitation:

Air agitation should be moderate but, above all, uniform.  Alternatively, agitation may be carried
out with the working solution being circulated by means of a centrifugal pump.  Immersion times
will have to be increased where agitation is insufficient.

CONSUMPTION:

ALKALINE ZINC

ACID ZINC

TRI BLUE 556

5 ml (6.4g) per m2 +

5 ml (6.4 g) per m2 +

Nitric Acid (42o Be)

8 ml (11.2g) per m2 +

5 ml. (7.0 g) per m2 +

These are average values, which will vary depending on the drag-out on the work. The nitric acid
figures are given as starting point values for initial plant dosage.  These should be checked and
altered to suit any given installation.

TESTING AND REPLENISHMENT:
pH:

The pH should be checked frequently, at least every 4 hours during operation.  Should it fall out with the desired range, it should be corrected with either nitric acid or sodium hydroxide solution.

All the above is based on our in-house experiments in totally controlled conditions and no warranty or guarantee covertly or overtly is implied hereon. 

ANALYTICAL CONTROL OF WORKING BATH:

1. Take a 20 ml sample of working solution into a suitable flask and dilute to about 150 ml. with   
   de-ionized water.
2. Add 10 ml of Sodium hydroxide (20 % wt/v) solution and heat to boiling.
3. Add sodium peroxide in increments of 0.5 gm. until the depth of the brown colouration  
    produced is stable. Simmer for 30 minutes.
4. All to thoroughly cool then add 20 ml. concentrated Hydrochloric acid, 10 ml of Potassium
    Iodide (10%) solution and 2 g. Ammonium bifluoride.
5. Titrate using 0.1 N. Sodium Thiosulphate until the appearance of a pale green colour. 

Calculation:

Reading – 1.42 = ml. /l of TRI BLUE 556 

TROUGBLESHOOTING GUIDE 

DEFECT

POSSIBLE CAUSE

SOLUTION

Blue with yellow tingers

- pH too low
- Immersion time too long

- Check and adjust pH
– Reduce immersion time

Yellow spots

- Insufficient rinsing
– Insufficient activation

- Improve rinsing
– Check nitric acid activation

Blue with green tingers

- pH too low
– Concentration too low
– Immersion time too short

- Check and adjust pH
– Add TRI BLUE 556 at 2 ml/l
– Extend immersion time

Process Sequence: Pre & Post – Treatment

  • A pre-rinse in water acidified with Nitric acid is recommended. 
  • After acid any cyanide zinc, use a concentration of 0.2% of 42oBe acid. 
  • After alkali, non-cyanide zinc, use concentration of 1.0% of 42o Be acid

The final water rinse after TRI BLUE 556 is usually run at about 60o C

 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.

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TRIVALENT BLAK PASSIVATE

TRIVALENT BLAK PASSIVATE
FOR HIGH CORROSION RESISTANCE ON ZINC/IRON

TRIBLAK is a passivate process on Zn/Fe totally free of hexavalent chromium designed to give a black aspect combined with high corrosion resistance properties even after thermal shock until 120ºC. It is a two step process consisting in trivalent chromium based passivate combined with an organo-mineral top coat.

After the passivate step, the resulting parts show a dark but slight iridescent aspect. The second step will result in a homogenous black colour.

The process should be applied on alkaline Zn/Fe bath.

It may be plated either on rack or barrel.

The iron content in the zinc-iron deposit should be comprised between 0.5 and 0.8%.

MAKE UP

The make up of the bath will be conducted with B and C, the maintenance will be conducted with A and B.

TRIBLAK PASSIVATE FOR 100 Ltr BATH:

1.     Fill the tank approximately one third full with DI water.
2.     Slowly add 4.0 L of TRIBLAK C.
3.    Add one third of DI water
4.    Add 25 L of TRIBLAK B

Make up the operating level, check the pH and eventually adjust it at 2.5 with sodium Hydroxide solution at 50% or with A. Let the bath stabilize for approximately 24 hours before operating. As pH may derive, it is necessary to check it before operating the bath. Once the bath is operating, avoid sodium hydroxide additions leading to destabilization of the solution. In case of pH decrease (due to an excess of acid part addition, it is advised to wait 2 to 4 hours before working again in the bath).

OPERATING CONDITIONS
  Optimum Range

TRIBLAK C 

 40 ml/l    30 – 50 ml/l

TRIBLAK B

250 ml/l   230 – 270 ml/

pH

2.5  2.4 – 2.7

Temperature

25ºC 22 – 30ºC
Immersion time  75 sec 45 – 120 sec.
Agitation Barrel or basket rotation  
Rack

Air agitation

 

Operating parameters will be optimized in order to achieve a layer weight comprised between 0.5 and 1 mg Cr/dm². The upper zinc content should be maintained under 15 g/l.

pH:

pH correction must be moderate and above all uniform for rack application. As an alternative, mechanical agitation with the help of a centrifugal pump may be used. Immersion times will perforce be longer if the agitation is insufficient or absent. For barrel application, it is necessary to adapt the barrel or basket rotation speed in order to minimize the shocks on the parts.

TOP COAT

The performance of the layer will strongly depend on the quality of the rinses (absence of Hexavalent Chromium). Two specific rinses are required before top coat application. Concerning the application mode of the top coat, please refer to the corresponding technical data sheets.

SOLUTION MAINTENANCE AND CONTROL
TRIBLAK PASSIVATE

Frequently Check the pH, at least every 4 hours of operation. Regular replenishment of the TRIBLAK bath is advised. The following theoretical data will usually maintain good results.

CONSUMPTION PER 1m2 OF PLATED SURFACE:

TRIBLAK 627 PART A – 8 – 20 ml
TRIBLAK PART B – 40 – 120 ml
These are average consumption values that will vary depending on the dragout on the treated parts. The pH has to be adjusted with PART A.

OPERATING SEQUENCE:

After Zn/Fe Plating
HNO3 0.5% Activation
Rinse
TRIBLAK passivate
Specific Rinses

For RACK
Draining for 60 cm diameter baskets
Drying – 15 min, 80ºC on parts, 250 rpm for 60 cm diameter baskets

For BARREL
Cold Spinning – 2 to 5 min max at 250 rpm
Dry spinning – 15 min80ºC on parts, 250 rpm for 60 cm diameter baskets

EQUIPMENT

Tanks for trivalent chromium passivate solutions can be used for TRIBLAK in existing lines. The tanks should preferably be made from or lined with a suitable plastic material, resistant to strong acid. It may be necessary to heat the solution where this is the case, use thermostatically controlled immersion heaters sheathed in graphite or Teflon (Silica must not be used). Even mixing of the solution when used by rack application requires air agitation. The tube bank should be made of PVC and fitted with a throughput control valve. For the finish tank equipment, [please refer to the Corresponding technical data sheet.

HEALTH & SAFTY:

TRIBLAK PASSIVATE: The supplied concentrates and the working bath are acidic solutions containing fluoride. Handling precautions must take (wear gloves, safety glasses/goggles and boots). The user should pay strict attention to the advice given on the labels and health and safety sheets.

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.

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ULTRA PASS III

ULTRA PASS III
Trivalent blue passivate for alkaline and acid zinc

Ronuk ULTRA PASS III is trivalent chromium based process and provides a blue passivate film on zinc deposits, particularly on sulfate-based coatings. The appearance is a bright blue protective film. ULTRA PASS III is suitable for rack, barrel, and strip or reel-to-reel plating installations.

ULTRA PASS III is compatible with aqueous Kemseal 23 RG sealants, which may be applied over the passivate to enhance corrosion performance.

ULTRA PASS III provides an excellent hexavalent chromium free base for polyvinyl fluoride coatings, commonly used in reel-to-reel production. Adhesion is maintained even after post-forming.

MATERIALS REQUIRED

ULTRA PASS III Nitric Acid Density – 1.32g/cm3

EQUIPMENT REQUIRED

Tanks should be of acid resistant material. Tanks may be of steel lined with Koroseal or other approved liners such as polypropylene. Heaters must be Teflon coated or of Titanium.

MAKE-UP

For 100 liters 5 to 10 liters ULTRA PASS III
0.1 to 0.4 liters Nitric acid, Density. 1.32 g/cm3 Balance Water

OPERATING CONDITIONS

The appearance and the anticorrosion effect of the passivation layer depend to a large extent on the pH value, the exposure time, temperature and concentration of the passivating solution. The following process conditions are recommended:

                 

Rack

Barrel

Strip or Reel-to-Reel

ULTRA PASS III

5 to 10%

7 to 10%

          7%

pH

1.8 to 2.0

1.5 to 1.7

1.4 to 1.7

Immersion Time

50 – 90 Secs

20 – 40 Secs

20 Secs

Temperature

20 to 30 ºC

20 to 30 ºC

20 to 25 ºC

Drying temperature

70 to 100ºC

70 to 100 ºC

70 to 100 ºC recommended

Note: With rack systems air agitation at 10 to 20 cubic meters per square meter of surface area is recommended.

MAKE-UP
  1. Fill the passivate tank ¾ full with water.
  2. Add the required volume of ULTRA PASS III
  3.  Adjust to final volume with water.
  4. Adjust pH with nitric acid. (Adjust pH upward with dilute sodium hydroxide).
  5. Adjust solution temperature to proper range.
SOLUTION MAINTENANCE

The following analytical procedure is used to maintain the concentration of ULTRA PASS III in the operating solution.pH adjustments are carried out with nitric acid to lower the pH or dilute sodium hydroxide to raise the pH.

CONTROL

Use only analytical reagent grade chemicals and deionized or distilled water in the following analytical procedures.

ANALYTICAL PROCEDURE:

Pipette out 10 ml of the working solution into a 300 ml Erlenmeyer flask. Add 100 ml of D.I. water, 2 ml of 20 %(v/v) Sulphuric Acid , 4-5 ml of Silver nitrate solution, 1to2 grams of ammonium Per sulfate, and a boiling bead. Place the flask on the hot plate and boil the solution gently for 15 to 20 minutes. Keep the volume above 75 ml by adding D.I. water if necessary.  Remove the flask from the hot plate and cool to room temperature. Add 10 ml of potassium iodide solution; titrate with 0.1 N Sodium Thiosulfate solution until the solution being titrated turns a light yellow. Add 1 ml of starch indicator and continue titrating to a clear light blue-green endpoint.

Calculation:

% Volume ULTRA PASS III = B.R. X Normality of Sodium Thiosulphate x 6.67

Container Information:

Keep containers tightly closed. Loosen closure cautiously when opening. Wash thoroughly after handling. Do not reuse containers, wash before disposal. Improper disposal or reuse of container maybe dangerous and illegal.

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.

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ZINCOBLACK

ZINCOBLACK
PROCESS

Black Chromatization on Zinc:

A process to develop ‘Black’ film on Zinc Deposits and on Zinc based Die-Casting. The reflectivity i.e. brightness of this is highly corrosion resistant and can stand almost 100 Hrs. salt spray test. The black film is a good base for lacquering and or painting. Freshly plated articles can be directly processed in this solution while stored articles need to be activated by passing through a mild alkaline cleaner. However, a dip 4-5 g/l Chromic Acid solution is absolutely essential.

Warning:

pH plays a very critical role in colour development i.e. intense ‘Black’ is obtained at lower pH.

Equipment:
  • Arrangement for mild air agitation or article movement.
  • Stainless steel container or PVC or PP tank
Preparation of Solution:
  • Fill the tank with distilled or de-ionized water (75% of required volume).
  • Add the required quantities of ZINCOBLACK BL- A and ZINCOBLACK BL- B while stirring.
  • Make up to volume by adding required quantity distilled and/or de-ionized water.
  • Stir to mix well
Operating Conditions:
  • ZINCOBLACK BL- A     :           100 ml/l
  • ZINCOBLACK BL-B      :             80 ml/l
  • Temperature                :           Room
  • pH (between)               :           1.3 & 2.0
  • Time (between)            :           1.0 & 2.5 minutes depending upon the use of the

                                    solution. (i.e. fresh solution needs less time).

Post Operation Treatment:
  • Treated articles to be cleaned under running water.
  • Allow to dry in air.
  • Do not touch fresh film.
Maintenance:

This could be done by analysis only.  Analysis methods available on your request.

Note

All solution are acidic and need all the relevant working precautions.

DISCLAIMER:-

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.

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ZINCOBLACK

ZINCOBLACK
PROCESS

Black Chromatization on Zinc:

A process to develop ‘Black’ film on Zinc Deposits and on Zinc based Die-Casting. The reflectivity i.e. brightness of this is highly corrosion resistant and can stand almost 100 Hrs. salt spray test. The black film is a good base for lacquering and or painting. Freshly plated articles can be directly processed in this solution while stored articles need to be activated by passing through a mild alkaline cleaner. However, a dip 4-5 g/l Chromic Acid solution is absolutely essential.

Warning:

pH plays a very critical role in colour development i.e. intense ‘Black’ is obtained at lower pH.

Equipment:
  • Arrangement for mild air agitation or article movement.
  • Stainless steel container or PVC or PP tank
Preparation of Solution:
  • Fill the tank with distilled or de-ionized water (75% of required volume).
  • Add the required quantities of ZINCOBLACK BL- A and ZINCOBLACK BL- B while stirring.
  • Make up to volume by adding required quantity distilled and/or de-ionized water.
  • Stir to mix well
Operating Conditions:
  • ZINCOBLACK BL- A     :           100 ml/l
  • ZINCOBLACK BL-B      :             80 ml/l
  • Temperature                :           Room
  • pH (between)               :           1.3 & 2.0
  • Time (between)            :           1.0 & 2.5 minutes depending upon the use of the

                                    solution. (i.e. fresh solution needs less time).

Post Operation Treatment:
  • Treated articles to be cleaned under running water.
  • Allow to dry in air.
  • Do not touch fresh film.
Maintenance:

This could be done by analysis only.  Analysis methods available on your request.

Note

All solution are acidic and need all the relevant working precautions.

DISCLAIMER:-

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.

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