ZN-418
Non-Cyanide Alkaline Zinc

DESCRIPTION:

The Triple-s ZN-418 process provides extremely bright zinc deposit, suitable for rack and barrel operation. The process is distinguished by its non-toxicity, stability, economy and ease of operation. ZN-418 process has an unusually good brightness range, comparable to conventional cyanide zinc plating. Deposits can be treated in clear chromate conversion coating dips to give a final blue bright finish, or full color passivity. Deposits meet the salt spray requirements or federal sep. Q-Q-Z 235.

OPERATION INSTRUCTION:

Zinc Oxide (pure) 10- gr/l 1-2 oz./gal.
Sodium Hydroxide 100- gr/l. 10-12 oz./gal.
Ratio NaOH / Zn 10:1 gr/l. 10:1
Zn-418 C Carrier 10- cc/l. 1 %
Zn-418 B Brightener 10- cc/l. 1%
Zn-418 P Purifier 5- cc/l. 0.5%
Temperature 20-35 º C. 70-100º F.
Cathode current density ----- -----
Barrel 0.5 - 2 A./dm2 5-20 ASF.
Rack 0.5 - 4.6 A./dm2 5-20 ASF.
Anode to cathode area 1:1 - 2:1 1:1 - 2:1

Solution Make up Procedure:

  • Fill a properly cleaned tank to 50% of total volume with top water.
  • Add caustic soda and zinc oxide and thoroughly mix.
  • Fill with water to balance of the tank and allow the solution to cool.
  • Add 418-Brightener, carrier and purifier and thoroughly mix.
  • Since most of the zinc oxides are impure, an 8 hour session of dummying is required to purify the solution in order to obtain maximum brightness.
  • The bath is now ready for operation.
----- ----- (OPTIMUM)
Zinc: 1.0 - 1.25 oz./gal.
8 - 1.25 g.p.l.		 12 oz./gal.
10 g.p.l.
Caustic soda: 10 - 15 oz./gal.
75 - 115 g.p.l.		 12 oz./gal.
100 g.p.l.
Temperature: 70 - 90 ºF. 75 º F.

Zinc Metal:

Use 99.9% Zinc ball or zinc ingots steel anode baskets are normally used. Maintain the metal content by increasing or decreasing the zinc anode area. To maintain a 1 to 1 ratio of anode to cathode area it may be necessary to use steel anodes removal of zinc anodes which is advised during the weekend periods.

Caustic Soda:

High purity grade is recommended. Maintain a minimum caustic to zinc ratio of 10:1.

Voltage & Current Density:

For rack up to 8 volt and for barrel up to 15 volt may be employed. A working range of 5-20 amperes per square foot (asf) is recommended.

Maintenance:

  • Zn-418 C Carrier should be added at the rate of 1/2 gal. to 1 gal. per 10.000 a/h.
  • Zn-418 P Purifier should be added at the rate of 1 quart per 10.000 a/h.
  • Zn-418 B Brightener should be added at the rate of 1/2 to 1 gal. per 10.000 a/h.

Cleaning Cycle:

  • Alkaline soak cleaner.
  • Water.
  • Electro cleaner.
  • Water.
  • 50% Muriatic Acid.
  • Water (2 station counter flow).
  • Alkaline zinc plating.
  • Rinse (2 station counter flow).
  • ½ % Nitric Acid dip.
  • Chromate (Blue bright, yellow, olive drab or black).
  • Rinse.
  • Rinse again.
  • Dry.

EQUIPMENT:

All equipment used in cyanide zinc plating systems may be used with Alk2V3 alkaline non-cyanide zinc bath.

Tank: A regular steel tank may be used.
Anodes: Use special high grade (SHG 99.99% pure) zinc balls or slab zinc anodes.
Anode baskets: Steel baskets are recommended. We do not recommend titanium baskets because of their high resistance properties.
Anode bags: Nylon or polypropylene bags are optional.
Anode bars: Use copper anode bars, preferably covered with plastic over all but the contact areas. Submerged steel anode bars can also be used.
Agitation: This is recommended, but not essential. A moving cathode rod agitation method is preferable, but an agitation effect can also be obtained by using filtration or pumping to produce solution movement.
Filtration: This is highly recommended, but is not always essential. Use a 10-25 micron filter cartridge packed with a non-cellulose filter aid (preferred) or activated carbon. Filtration speed should be 1 to 2 tank turnovers per hour.
Rectifier: Barrel: up to 18 volts remote or tap switch.
Rack: up to 9 volts remote control is recommended.
Temperature control: The Zn-418 system is tolerant up to 120 º F. We recommend that the tank be equipped with heating and cooling coils, where necessary, to keep the temperature within prescribed limits.

Analytical Procedures:

ZINC:
Reagents:
  1. 0.1 M Disodium EDTA solution.
  2. Ammonium buffer solution.
  3. 4% formaldehyde solution.
  4. Eriochrome black T indicator.
Procedure:
  1. Pipet a 2 ml. sample into a 400 ml. beaker.
  2. Add 200 ml. Deionized water.
  3. Add 30 ml Ammonia buffer solution.
  4. Add 10 ml. 4% formaldehyde solution.
  5. Add sufficient Eriochrome black T indicator to give a purple color.
  6. Titrate with standard EDTA solution until color changes from a purple to blue.
  7. Calculation: ml of titration X .44=zinc oz./gal. or ml. of titration X 3.3 = gm. of zinc / liter.

(caustic) Sodium Hydroxide:
Reagents:
  1. 10% Sodium Cyanide solution.
  2. (0.95N) Sulfuric Acid.
  3. Indigo Carmine Indicator.
Procedure:
  1. Pipet a 5 ml. sample into a 125 ml. Erlenmeyer flask.
  2. Add 10 ml. of 10 % Sodium Cyanide.
  3. Add 2 drops of Indigo Carmine Indicator.
  4. Titrate with 0.95 N sulfuric acid until color changes from yellow to blue violet.
  5. Calculation: ml of sulfuric acid titration=caustic in oz./gal. or ml. of sulfuric acid titration X 7.5 = Caustic in gms./L.

The information stated herein is based on information and tests we believe to be reliable. The accuracy or completeness thereof is not guaranteed. Since conditions of use are outside our control, user shall, before using, determine the suitability of the product for his intended use and user assumes all risk and liability in connection therewith.
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