ELECTROLESS NICKEL COATING
Electroless Nickel coating is a coating process, which is applied to protect the parts against corrosion, to prevent abrasion, to reduce surface friction coefficient and to increase corrosion resistance.
Main fields of application are:
• In engineering applications and automotive industry,
• Petroleum and gas industries,
• Aerospace industry,
• Chemical industry,
• Hydraulic and Mining industries,
• Plastic industry,
• Electronic and computer industries.
Electroless Nickel is the nickel coating process, which is performed without applying any outside power supply (power current).
In this electroless nickel solution, there are nickel ions, reducing chemicals and additive chemicals, which make pH of the solution stable. Depending on the purpose, electroless-nickel solutions with various amounts of phosphor can be used. Electroless Nickel coating process is applied after the surfaces are specifically activated. Regardless of the surface features of the parts to be coated, the coat thickness is equal on the entire surface of the electro-nickel coated part. This feature is one of the most important advantages of electroless nickel coating.
Figure 1: Differences of electrolitic-nickel coating and electroless-nickel coating part as section.…
1. ENGINEERING APPLICATIONS
Electroless nickel coating process is applied on parts made of iron, steel, stainless steel, aluminum, copper, brass and alloys to protect them against corrosion and to increase their abrasion resistance, to reduce friction resistance on metal parts. It is applied on brakes, injectors, clutch, etc. in automotive industry.
Photo 1: A clutch part which is coated electroless-nickel in automotive industry.
2. PETROLEUM AND GAS INDUSTRIES
It is applied on valve bodies, equipment, retaining rings, gaskets, separator parts, fasteners, bolts, compressor blades, gas turbine absorption equipment, pumps, etc…
3. AEROSPACE INDUSTRY
It is commonly applied on fuel injection pumps, carburetors, ABS systems and clutch systems, defrosting valves, aircraft engines, pump bodies, bolts etc.
4. CHEMİCAL INDUSTRY
Since electroless nickel has a wide range of chemical resistance, it has a wide field of application in chemistry industry. Some examples are mixers, valves, reactor vessels and lids.
5. HYDRAULIC AND MINING INDUSTRIES
30-50 micron electroless nickel coatings applied on hydraulic cylinders and valves perfectly improve the corrosion and abrasion resistance of the equipment and prolong the life of the equipment. Electroless nickel applications to be made on boring equipment and drill bits used in mining industry will increase the lifespan of the equipment by far.
6. PLASTİC INDUSTRY
Electroless nickel has also found excellent fields of application in plastic industry. Electroless nickel coating process is applied to protect the surfaces that contact with cooling water against corrosion, and to protect plastic molds against abrasion, and it is applied on maintenance kits.
7. ELECTRONIC AND COMPUTER INDUSTRIES
Electroless nickel processes with more than 10% of phosphor are applied to increase corrosion resistance and to create a protective layer in order to help welding on diffusion barriers. The process is also used in coating of magnetic memory disks.