NON-CYANIDE ZINC-IRON PROCESS ZI NF E R S

Transcription

1 NON-CYANIDE ZINC-IRON PROCESS ZI NF E R S PHYSICAL PROPERTIES: ZINFER 591: Brown Liquid ZINFER 595: Yellowish Liquid ZINFER 596: Clear Liquid ZINFER 597: Brown Liquid DESCRIPTION: The ZINFER 590 S process is a non-cyanide zinc-iron plating system for rack and barrel application. ZINFER 590 S produces bright to brilliant zinc-iron deposits over the total current density and temperature ranges up to 30 C. It has an excellent covering and throwing power as well as a very high plating speed. Zinc iron plated parts can easily be passivated or chromated with our UNIFIX FE series resulting in an excellent corrosion resistance. Since the deposits achieved in the ZINFER 590 S process are extremely ductile, this process has special applications for parts which must be later on bent, formed or welded. OPERATING INSTRUCTIONS: Cathode current density: Anode current density: Voltage: up to 6 A/dm² for rack plating with agitation up to 2 A/dm² for barrel plating up to 4 A/dm² with steel anodes 6 12 Volt Temperature: C Efficiency: Anodes: % depending on Zn-content, organic content and current density Steel, nickel plated steel or nickel Anodes must be cleaned once within half a year. Zinc solution: in a separate tank, % zinc DIN 1706 Anode to cathode ratio: 1 : 1 2 : 1 H. Donsbach Rev /5

2 Analysis Value: Rack Barrel Zn Metal 7 10 g/l 7 14 g/l Iron mg/l mg/l NaOH g/l g/l EQUIPMENT: Tanks: Exhaust: Filtration: Agitation: Steel, rubber or PVC lined Is recommended. To avoid roughness of deposits, continuous filtration is recommended. Cathode agitation of 3 5 m/min. Barrel rotation of 4 6 m/min. MAKE-UP FOR 100 LITRE PLATING SOLUTION: Rack Barrel Zinc oxide 1.0 kg 1.2 kg NaOH 12.0 kg 14.0 kg ZINFER l 0.6 l ZINFER l 1.0 l ZINFER l 0.6 l ZINFER l 1.0 l Dissolve caustic soda in one fifth of the required amount of water, if possible de-ionised water. Then add zinc oxide, stir well, and dissolve. Allow to cool down to room temperature and add up with water to 90 %, then add the required amount of ZINFER 590 S additives. Fill the bath up to desired volume with water. It is suggested to electrolyse the solution for several hours at normal current densities before starting regular plating. H. Donsbach Rev /5

3 MAINTENANCE: We recommend to make frequent, small additions of all additives to insure constantly good results. If brightness of the work falls off rapidly, it is recommended to make a chemical analysis of the plating solution and bring the bath back to normal conditions, before making any large additions of additives. The additives cannot compensate improperly balanced plating solutions. Consumption per 10,000 A/h: Iron Solution ZINFER 591: Brightener ZINFER 595: Brightener ZINFER 596: Make-Up ZINFER 597: Rack / Barrel l depending on drag-out l l depending on drag-out GENERAL INFORMATION: Zinc: The zinc has to be dissolved in a separate tank by using zinc anodes % in iron or nickel plated iron baskets.the zinc solution will be added to the bath using a filter pump. Iron: The content of iron in the electrolyte will be adjusted by ZINFER 591. As the percentage of iron in the deposit is approx % per 1 kg zinc, approx. 4 8 g iron will be plated. This amount of iron is dissolved in ml. Iron Solution ZINFER 591: It is recommended to control the iron content in the electrolyte as well as in the deposit (AAS or photometer). For a good chromatability and corrosion resistance it is important to maintain the iron content in the deposit between % (optimum %). H. Donsbach Rev /5

4 The following parameters influence the iron content in the deposit: The ratio Fe : Zn in the electrolyte. It should be 1 : 100. Higher content of iron in the electrolyte increases the content of iron in the deposit. Higher content of zinc in the electrolyte decreases the content of iron in the deposit. All parameters which decrease the current efficiency for the zinc plating increase the percentage of iron in the deposit. These are: Lower zinc content High carbonate content Too low temperature High current density Weak agitation At a current density of 1 A/dm² and 100 % current efficiency 0.29 µm zinc-iron will deposited. The electrolyte will be controlled by analysis and in hull cell. HULL CELL TEST: With magnetic stirrer. Current density rack: 1.5 A Current density barrel: 1.0 A Time: 10 min to check the brightness 60 min to check the adhesion POST TREATMENT: After activation in a 0.1 Vol.% nitric acid parts will be passivated or chromated in specially developed products like our Unifix FE systems and if required with final Sealer treatments. H. Donsbach Rev /5

5 BARREL PLATING: The zinc-iron plating in barrel requires special measures, because in this case additional parameters influence the plating and the chromatability. These are: Barrel movement Barrel filling Exchange of the electrolyte in the barrel The current conditions during plating etc. For that reason an optimum plating has to be adjusted at each plant. The plating data for rack plating cannot be used for barrel plating. SAFETY PRECAUTIONS: See Material Safety Data Sheets GUARANTEE: Above instructions and recommendations are the result of intensive testing and shop experiences. They are for your information, only. Our guarantee extends to the continuous quality of our products as they leave our factory and not to their usage in the field, which is a factor beyond the control of a supplier. H. Donsbach Rev /5