Pump Technology for Autocatalytic Nickel-Phosphorus Baths
Two robust solutions
Pump Technology for NiP Baths
Electroless nickel, also known as nickel-phosphorus or NiP, is an autocatalytic process. Deposition takes place without an external plating current as soon as a catalytically active surface comes into contact with the bath. For pumps, the tendency to plate out, clearances and cleanability are therefore just as important as chemical resistance.
Deposits on Plastic Surfaces
PVDF and PP are not initially catalytically active. However, contamination or unstable bath conditions can create NiP nuclei. Once a NiP layer has formed, further nickel-phosphorus deposits on it; impeller, bearing and containment-shell clearances can consequently narrow or become blocked.
Stainless steel with anodic protection
With stainless-steel pumps, controlled anodic protection can maintain the wetted surfaces within a passive potential range and reduce plate-out. Pump geometry, reference electrode and potential control are engineered jointly with the plant manufacturer and bath supplier. The suitability of 1.4571 stainless steel must still be assessed for the specific bath chemistry, temperature and additives. Suitable series are UP, UP-DO and, on request, TE.
PVDF with cleaning strategy
PVDF is chemically well suited to many mildly acidic, hypophosphite-based NiP baths. Plate-out is managed through filtration, bath management, sufficient clearances and defined inspection and cleaning intervals. The MPN in PVDF is a suitable hermetically sealed solution; depending on the installation, U or T may also be used. A stainless-steel pump without properly engineered anodic protection is not automatically the better solution.
Advantages of SCHMITT solutions
Stainless steel with anodic protection or PVDF with a defined cleaning strategy.
Magnetic drive as well as single or double-acting mechanical seal.
Clearances, inspection access and cleaning intervals are matched to bath condition and plate-out.
Solutions for external installation, tank-top mounting and immersed operation.
Pump selection in collaboration with the bath supplier, plant manufacturer and operator.
Cleaning access and disassembly are already taken into account during the design phase.
Recommended Pumps for Electroless Nickel
- Robust and durable design made from thick-walled, solid stainless steel components
- Compact close-coupled design
- Easy installation
- Suitable for high temperatures
- Hermetically sealed, magnetic drive, PP or PVDF
- Up to 95 °C, flow rate up to 35 m³/h, head up to 32 m
- Extremely proven pump, used in more than 10,000 applications
- Insensitive to insufficient lubrication and partial dry running due to generously dimensioned plain bearings – no plug-in shaft
- Virtually maintenance-free in normal operation due to generously dimensioned plain bearings
SCHMITT Pumps
Horizontal plastic pumps
Horizontal Stainless-Steel Pumps
