Cyanide Free Alkaline Zinc Plating Process

•  Cyanide Free Alkaline Zinc Plating     Process 

            

A. Alkazin 111 Process Economical robust High-Performance Cyanide Free Alkaline Zinc process suitable for both rack & barrel

PROCESS DESCRIPTION ALKAZIN 111 is an alkaline zinc plating process providing bright, fully ductile zinc Deposit over a broad current density range for both rack & barrel operation. It Provides good LCD coverage and excellent metal distribution thereby improving Resistance to corrosion and free from poisonous cyanide, making it easy to Handle. Superior throwing power provides for increased rack population. Excellent cathode efficiency provides rapid plating in low current density areas. This reduces the time to deposit minimum plating thickness in recessed areas, without excessive thickness in the high current density areas and Cyanide –free Economical to operate & it has high tolerance to metallic contamination and achieves a long solution life.

Make-Up and Maintenance of the Operating Solution PERAMETERS RANGE Barrel RACK Zn Metal 7-14 gm/l Sodium hydroxide(NaOH) 120-140 gm/l Temperature C0 20-35 Same Same Cathode Current Density 0.5-2.5A/dm2 (5-25A/ft2) 0.5-1.5A/dm2 (5-15A/ft2) 1.0-2.5A/dm2 (10-25A/ft2) Anode Cathode ratio 1:1 Same Same Voltage 3-15 volts 9-15 volts 3-6 volts Barrel Rotation NA 4-8RPM NA ALKAZIN 111 Carrier A 6-10 ml/l ALKAZIN 111 Brightener B 1-2ml/l ALKAZIN 111 Purifier C 6-10ml/l ALKAZIN 111 Conditioner 10-12ml/l Barrel Rotaion 4-6RPM 5RPM NA These concentrations may be slightly higher in systems utilizing off-line, external zinc generators. Also, if potassium hydroxide (KOH) is used in place of sodium hydroxide (NaOH), increase the concentration by approximately 20%. ** For decorative applications, we recommend 20-28˚C (68-82˚C). *** Use of an external zinc generator is recommended. Note: Air agitation is not recommended because it will increase the rate at which carbonates build in the plating bath Make Up Clean the tank to be used for the new plating solution. When using other materials check the heat resistance. Fill the Tank 1/2 with D M Water .Make-up the base electrolyte (zinc metal and NaOH or KOH) per composition suggested above, You can also bring up required Zinc Metal and Caustic by using basic chemicals. Allow solution to cool to 25˚C (77˚F). Analyze the solution. Add the required amounts of ALKAZIN 111 Purifier C and Conditioner. Mix well. 5. Add the required amounts of ALKAZIN 111 CARRIER and ALKAZIN 111 Brightener. Mix well. Maintenance & replenishment of bath Daily analysis of Zn metal and caustic soda is highly recommended to maintain Optimum conditions. Addition of ALKAZIN maintenance concentrate to maintain Zn and OH in bath is Recommended. Addition of 1 ml / L 111 Brightener B Concentrate increases 0.5 gm / L NaOH in bath. ALKAZIN 111 Carriers A: prevents burning at HCD & blister formation. ALKAZIN 111 Brightener B: improves brightness in deposit. Excess of this can result in streaking. ALKAZIN 111 Purifier C: Helps remove metallic contaminants. ALKAZIN 111 Conditioner: Removes hardness in raw water. These alkaline zinc baths are less tolerant to impurities. Therefore pre-treatments should be perfect and a dip in 50 g / L NaOH to neutralize acid film is recommended prior to plating. Replenishment for 1000 Amp. Hrs.: ALKAZIN 111 Carriers A: - 90 – 200 ml ALKAZIN 111 Brightener B: - 60 – 100 ml ALKAZIN 111 Purifier C: - 20 – 60 ml ALKAZIN 111 Conditioner: - 40 – 100 ml Equipment:- Tank suitably lined mild steel. Anodes: 99.99% pure Zn Anodes and insoluble mild steel anodes to control Zinc Metal concentration. Mild agitation and continuous filtration through 10 μ cartridge filter is recommended. Process Sequence SOAK Clean Acid dip 50% HCl. Cathodic clean. RINSE 2X Pre-dip in 50% NaOH solution. Plate in Alkazyn bath. Rinse. Dip in 0.1% HNO3 prior to Chromating process. Chromate dip. Hot water rinse. Dry. Electroplate zinc. Operation Guide: Rinse water and concentrates Local waste treatment regulations vary considerably from area to area. Consequently, it is not possible to state the proper waste treatment procedure that will meet all requirements. Typically, however, neutralization of the solution, followed by precipitation the zinc metal, is all that is necessary. Standard treatment methods are satisfactory, as are proprietary methods. Safe Handling This process addition agents are safe to handle however, the preparation, maintenance, and disposal of solutions containing them require the handling of highly alkaline materials. Avoid contact with the skin or eyes. Wear proper protective clothing. If solution is splashed in the eyes, flush immediately with large volumes of cold water, and rinse with a 5% boric acid solution, and seek medical assistance as soon as possible.