Electroless Nickel Plating (ENP) is an autocatalytic chemical reduction process that deposits a completely uniform nickel-phosphorus alloy coating across all internal bores, blind holes, and threads.
Engineering Specifications & Parameters
Hardness (As Plated)
48 - 52 Rockwell C (HRC)
Standard Specification
MIL-C-26074 / ASTM B733
Coating Thickness Uniformity
+/-0.001 mm across all internal/external features
Hardness (Heat Treated 400C)
68 - 70 Rockwell C (HRC)
Corrosion Resistance (High-P)
> 1000 hours Salt Spray (ASTM B117)
The Electroless Plating Advantage
Unlike electrolytic electroplating which concentrates excessive plating on exterior sharp corners while starving deep internal bores, ENP deposits with 100% geometric uniformity across all surfaces in contact with the chemical bath.
Phosphorus Content Classes
Low Phosphorus (1-4% P): Maximum as-plated hardness (up to 60 HRC).
Medium Phosphorus (6-9% P): Standard industrial balance of wear and corrosion resistance.
High Phosphorus (10-13% P): Superior resistance to harsh acids, saltwater, and chemical attack.
Post-Plate Baking for 68 HRC Hardness
Baking ENP-coated parts at 400 C (752 F) for 1 hour induces nickel phosphide precipitation, increasing hardness from 50 HRC to 68-70 HRC (harder than hard chrome).
Frequently Asked Questions
Why is Electroless Nickel superior to Electroplated Chrome for complex manifold blocks?
Electroless plating requires no electrical anodes; every internal cross-drilled fluid channel receives the exact same coating thickness.
Does Electroless Nickel Plating cause hydrogen embrittlement in high-strength steels?
High-strength steels (>1000 MPa) require a post-plate hydrogen relief bake at 190 C within 4 hours of plating to prevent catastrophic embrittlement.
