Electroless Nickel Plating (ASTM B733)

Electroless nickel is an autocatalytic nickel-phosphorus deposit — no rectifier, no current-density gradient — so it plates uniform thickness on every wetted surface, including bores, threads, and complex geometry. Hardness is tunable by phosphorus level and heat treatment. Gleco plates electroless nickel to ASTM B733, MIL-C-26074, and AMS 2404 at our AS9100D and ISO 9001:2015 certified, ITAR Registered Texas plants.

AS9100D

ISO 9001:2015

ITAR Registered

Rowlett & McAllen, TX

📍 Available at: Rowlett, TX (Dallas–Fort Worth) & McAllen, TX (Rio Grande Valley)

Electroless Nickel Specifications

Governing specs	ASTM B733; MIL-C-26074 / AMS-C-26074; AMS 2404
Phosphorus types (B733)	Type I (no P req); Type II 1–3% (low P); Type III 2–4%; Type IV 5–9% (mid P); Type V over 10% (high P)
Service condition / thickness	SC0 0.1 µm; SC1 5 µm; SC2 13 µm; SC3 25 µm; SC4 75 µm
Heat-treat classes	Class 1 as-deposited; Class 2 heat-treated to harden (850 HK100 min); Classes 3–6 adhesion bakes for aluminum/beryllium
Hardness	~550–650 HV as-plated; 850–1,000+ HV heat treated
Corrosion	High-P (Type V) gives the best barrier corrosion resistance
Typical uses	Valves, molds, firearms, hydraulics, aluminum housings; wear + corrosion in one coating

See also: nickel plating overview, bright nickel, sulfamate nickel, electroless nickel.

Electroless nickel plating line at Gleco Plating — The electroless nickel line. Because deposition is chemical rather than electrical, thickness is uniform across recesses, blind holes and internal surfaces.

Electroless Nickel FAQ

What is the difference between electroless and electrolytic nickel?

Electroless nickel is autocatalytic — deposited by chemistry, not electrical current — so it plates with near-perfect uniformity on every wetted surface, including bores, threads, and internal features that electrolytic nickel cannot reach evenly.

What phosphorus level should I specify?

Low-phosphorus deposits are hardest as-plated; mid-phosphorus balances hardness and corrosion; high-phosphorus (over 10% P) gives the best barrier corrosion resistance. Tell us the environment and wear requirement and we will recommend the type per ASTM B733.

How hard is electroless nickel, and can you heat treat it?

As-plated hardness is roughly 550–650 HV. Heat treatment (typically to ASTM B733 Class 2) raises it to about 850–1,000+ HV, comparable to hard chrome, for wear applications.

How is corrosion resistance determined?

Corrosion performance is driven by phosphorus content, thickness, and porosity — high-phosphorus electroless nickel gives the best barrier protection. It protects as a barrier rather than sacrificially.

Can you hold thickness on bores and threads?

Yes. Because electroless nickel deposits uniformly regardless of geometry, we routinely hold tight thickness on bores, threads, and internal features where electrolytic processes build unevenly.

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Electroless Nickel Plating (ASTM B733)

Electroless Nickel Specifications

Electroless Nickel FAQ

What is the difference between electroless and electrolytic nickel?

What phosphorus level should I specify?

How hard is electroless nickel, and can you heat treat it?

How is corrosion resistance determined?

Can you hold thickness on bores and threads?

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