Alkaline zinc electrolyte with optimum coating thickness Distribution
Alkaline zinc-nickel ensures a uniform coating thickness distribution on the surface over a wide current density range and is free of cyanides. Especially for less complex shaped workpieces, which are deformed after coating with zinc electrolyte, a uniform coating thickness throughout is indispensable. Alkaline zinc electrolyte is characterised by better ductility than acidic electroplated zinc-nickel and, as a basic zinc nickel electrolyte, offers the same high corrosion protection as an acidic zinc nickel electrolyte. The very good spreading produces a uniform layer build-up even on profiled workpieces, effectively preventing the coating from flaking. Alkaline zinc electrolyte was developed for the galvanising process using bath electroplating and pin electroplating / tampon electroplating.
Application range of zinc nickel electrolyte
Zinc-nickel alkaline is always used when high corrosion protection and a uniformly thick coating are required. The nickel content of approx. 14% increases the corrosion resistance of workpieces treated with zinc-nickel alkaline fivefold and offers the highest cathodic corrosion protection. This is an argument in favour of zinc-nickel alkaline, especially in corrosion protection. The further treatment of the workpieces after galvanising with zinc-nickel electrolyte is the same as for coating with conventional zinc electrolyte. Another special feature is that the nickel content of approx. 14% remains almost constant over a wide current density range.
Basic zinc electrolyte is suitable for the following metals:
- stainless steel - must be activated with nickel-strike beforehand
- aluminium - pre-treatment with aluminium activator required
Chrome and titanium are unsuitable for the zinc electroplating process.
Application instructions for galvanic zinc-nickel
All metals mentioned can be treated with galvanic zinc-nickel, whereby stainless steel and aluminium require an appropriate pre-treatment. As a basic zinc electrolyte, zinc-nickel alkaline is used both in bath electroplating and in pin electroplating / pad electroplating. In all processes, they achieve excellent results in the form of a uniformly strong and shiny layer thickness, which also remains stable during further processing of the workpiece by deformation.
Alkaline zinc electrolyte is processed at room temperature; however, it can also be heated slightly. The temperature range in which alkaline zinc electrolyte can be used for plating is between 15 - 60°C.
The zinc-nickel electrolyte can be further coated or chromated like any other zinc electrolyte.
Parameters (these may vary, please test):
- tank plating: 2.2-4.5V (approx. 3.5V recommended at 10cm distance)
- brush plating: 2.5-7V (approx. 5V recommended)
- current density: 0.9-8A/dm² (up to 12A/dm² with bath movement)
- working temperature: 15-35°C
- deposition rate: approx. 0.6µm/min at 4A/dm² and 20°C
- ph-value: 14
- tank plating: Graphite or nickel anodes
- brush plating / pen plating: Graphite or nickel anodes, alternatively stainless steel anodes
Anode on positive pole - Workpiece on negative pole
Before treatment, please thoroughly remove rust, oil and grease from the workpiece. Wear disposable gloves when handling to prevent contamination with skin grease.
Use appropriate protective equipment such as safety goggles and gloves when working with zinc electrolyte. Use only in well ventilated areas!
Labelling of the mixture:
Zinc-nickel plating solution
(contains sodium hydroxide, diethylenetriamine, nickel dichloride, nickel sulfate)
Signal word: Danger
H290 May be corrosive to metals.
H314 Causes severe skin burns and eye damage.
H317 May cause an allergic skin reaction.
H332 Harmful if inhaled.
H412 Harmful to aquatic life with long lasting effects.
P102 Keep out of reach of children.
P103 Read carefully and follow all instructions.
P260 Do not breathe dust/vapours/spray.
P280 Wear protective gloves and eye/face protection.
P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
P302+P352 IF ON SKIN: Wash with plenty of water.
P333+P313 If skin irritation or rash occurs: Get medical advice/attention.
P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P310 Immediately call a POISON CENTER/doctor.
P501 Dispose of contents/container according to regional/national regulations. Do not discard with household waste.