Electroless Nickel Plating (Nadcap accredited)
Uniform thickness...excellent corrosion protection...solderability...can replace stainless steel...eliminate the need for liquid LubricantsElectroless Nickel Plating is the deposition of a nickel-phophorous alloy onto a metal substrate without the use of an electrical current. The electroless nickel plating process utilizes an autocatalytic chemical reaction to deposit a reliable, repeatable coating of uniform thickness. This uniformity of deposit can, in some cases, eliminate the need for post-plate grinding. Electroless nickel demonstrates excellent corrosion protection, with similar lubricity properties to plated chromium. Electroless nickel effectively coats parts with sharp edges, deep recesses, seams, threads, and complex geometries. Chem Processing offers varying alloys of nickel and phosphorous, including:
- High Phosphorus (10% to 13%): superior corrosion protection; most resistant to acidic environments; greater than 65 Rc hardness with post-plate thermal treatment; amorphous deposit structure (the higher the amorphous nature of the electroless nickel coating, the better the corrosion protection)
- Medium Phosphorus (5% to 9%): best appearance; mixed amorphous/crystalline deposit structure
- Low Phosphorus (<5%): highest as-plated surface hardness (up to 60 Rc); most resistant to alkaline environments; best solderabilaty; lowest electrical resistance; crystalline deposit structure
- Nickel-Teflon®: increased lubricity; low reflectivity; can reduce or eliminate the need for liquid lubricants in some applications (see nickel-PTFE page for more information)
Chem Processing Inc. Electroless Nickel Plating Capabilities:
- AS 9100 certified and Nadcap accredited
- Boeing, GE Aviation, Honeywell, Eaton and Rockwell approved
- Plating thicknesses from 0.0001 to 0.0050 inches
- Precision masking for selective plating
- Salt spray corrosion testing per ASTM B117
- Post-plate hydrogen embrittlement relief
- Hardnesses up to 70Rc (high phosphorous with post-plate bake)
- XRF thickness analysis
- MIL-F-14072 (M265)
- SAE AMS 2404 & 2405
- MIL-STD-171 (1.4.3)
- ASTM B733
- ISO 4527
- ASTM B656
- HS 201 (UTC Aerospace Systems/Hamilton Sundstrand)
- PN 13.12 (UTC Aerospace Systems/Hamilton Sundstrand)
- 580-0766 (Rockwell Collins)
- 580-5296 (Rockwell Collins)
- SP 1046 (Woodward)
- The electroless nickel plating process is aqueous and takes place at a temperature of 200F.
- While the process applies a uniform coating on all geometries, adequate solution flow is required. Blind holes or obstructed areas may receive less coating.
- Stainless steels and non-ferrous substrates may require post-plate thermal treatment to improve deposit adhesion.
- High-phosphorous electroless nickel will often discolor when given post-plate thermal treatment for maximum surface hardness.
Common Applications of Electroless Nickel Coatings:
- Aerospace Components: For wear resistance, corrosion protection, chemical resistivity and lubricity on valves, pistons, engine shafts, engine mounts, compressor blades and other flight-critical components.
- Electrical Equipment: Due to solderability and conductivity properties.
- Packaging & Handling Machinery: Due to wear resistance, cleanliness and attractive finish.
- Chemical Manufacturing and Transport Equipment: Due to chemical resistance.
- Molds & Dies: Corrosion protection minimizes erosion and abrasion. Low coefficient of friction improves release.
- Food Service Equipment: For superior corrosion and wear resistance, attractive finish and cleanliness.
- Plastics Manufacturing Equipment: For durability and release properties on injection molds and extrusion dies.
- Oil & Gas Components: For corrosion protection in harsh undersea and underground environments for parts such as valves, pumps, pipe fittings and others.
- Printing Industry Equipment: For abrasion resistance on conveyance and chemical resistance on printer cylinders.
- Automotive Components: For wear protection and corrosion resistance on pistons, cylinders, gears, differential pinon ball shafts, fuel injectors, ball studs, transmission thrust washers, knuckle pins, hose couplings, heat sinks and others.
- Salvage: For restoration of parts to their original dimensions or to bring mis-machined parts into tolerance.
- Stainless Steel Replacement: Electroless nickel can serve as a cost effective replacement for 300 and 400 series stainless steel in some applications (see case study from firearms industry in this Products Finishing article).
FREQUENTLY ASKED QUESTIONS (FAQs)
- Which electroless nickel-phosphorous alloy gives the highest surface hardness? Low phosphorous (<5%P) electroless nickel gives the highest as-plated hardness. High phosphorous (10-13%P) gives the highest surface hardness when thermally treated.
- Which electroless nickel-phosphorous alloy gives the best corrosion protection? High phosphorous (10-13%P) provides the best corrosion protection because of the amorphous microstructure of the deposit. Thermal treatment to increase hardness will lower the corrosion protection of the deposit.
- Which electroless nickel-phosphorous alloy looks the best? Mid phosphorous (5-9%P) electroless nickel yields the brightest deposit. If the substrate surface finish is sufficiently smooth an almost mirrorlike finish can be achieved. High phosphorous (10-13%P) electroless nickel is also an attractive finish although slightly more matte.
- Which electroless nickel-phosphorous alloy deposit is most ductile? Low phosphorous (<5%P) electroless nickel is the least ductile. High phosphorous (10-13%P) deposits are the most ductile.
- Does electroless nickel decrease surface finish? Yes. Generally it decreases surface finish by about half, so if you are aiming for a final surface finish of 16rms, the pre-plate surface finish should be 8rms.
- Why are the thickness requirements so high for severe service conditions in electroless nickel specifications such as SAE AMS 2404? Electroless nickel protects the base material by a method called "encapsulation" as opposed to other plated metals which protect sacrificially due to their relative location in the galvanic series. The passive nickel serves as a barrier layer between the base material and the outside environment. The thicker the deposit, the less the likelihood of porosity allowing corrosion to initiate.
- Does electroless nickel require surface grinding after plating to meet dimensional requirements? Typically, no. Unlike hard chrome which builds on corners and points, electroless nickel builds evenly on all surfaces. It is also a controlled process that allows deposits to be controlled within a few microns.
- Can electroless nickel be substituted for hard chrome? Possibly, depending on the application. The hardness of thermally treated, high phosphorous electroless nickel plating approaches that of hard chrome. The lubricity of electroless nickel is not as high, but this is where electroless nickel Teflon can serve as substitute. High-build salvage is also better suited for hard chrome plating, which can be applied up to 0.020" where the upper limit of electroless nickel is around 0.006".
Chem Processing Inc. offers electroless nickel plating services to manufacturers across the United States. CPI is strategically located in the center of the country, with immediate highway access and minutes from Rockford Chicago International Airport, a major international air freight hub.