High-phosphorus electroless nickel plating (ENP 1012)

Maximum anti-corrosion
protection for critical
environments

High-phosphorus
electroless nickel plating

The high-phosphorus electroless nickel plating treatment, indicated as ENP 1012 (compliant with ASTM B733 Type V), is Deltar’s historic specialty: an autocatalytic nickel-phosphorus alloy with a P content ≥ 10.5% by weight.
The ENP process at Deltar has been active since 1974, the year of the first Italian installation carried out in collaboration with IBM and Enthone. The proprietary ENP 1012 formulation, completely non-toxic, was developed in the 1980s and introduced Deltar into the sector of machinery for the food and pharmaceutical industry.
It is the maximum anti-corrosion performance solution: the standard choice when the component must work in aggressive environments (marine, chemical, humid, petroleum) and resist over time without surface degradation.

Characteristics of the
ENP 1012 deposit

The high-phosphorus deposit has an amorphous (non-crystalline)
structure, which is the key to its anti-corrosion performance:

Amorphous structure free of grain boundaries, which eliminates
the micrometric porosity typical of crystalline coatings
Documented corrosion resistance >1,000 hours in salt spray
(ASTM B117 test, thickness 30 µm)
Thickness uniformity guaranteed on all geometries, holes,
cavities and undercuts (absence of the “edge build-up” effect
typical of electrolytic processes)
“As deposited” hardness: 500-600 HV
Hardness that can be increased up to about 1000 HV with
post-deposition heat treatment, values comparable to thick
hard chrome plating
Non-toxic deposit, suitable for contact with food

When to choose high phosphorus

High phosphorus is the correct choice when the component must:

Resist in marine, chemical, petroleum or high-humidity environments
Operate in the presence of acids, saline solutions,
atmospheres with H2S
Guarantee long-term anti-corrosion protection, even on limited thicknesses
Comply with international standards for Oil & Gas applications
Be intended for contact with food (food-grade applications)
Work in subsea, offshore, nuclear components where traceability
and reliability are critical

It is not the first choice when the dominant requirement is pure
mechanical hardness: in that case low-phosphorus ENP 23
“as deposited” offers superior performance.

Typical applications

Oil & Gas: valves, actuators, pump bodies, subsea components, valve trim
Chemical and petrochemical: reactors, exchangers, tanks, fittings
Nuclear: components with uniformity and traceability requirements
Aerospace: structural and precision components
Marine and offshore
Pharmaceutical and food: surfaces in contact with products
Defence

Technical reference data

Phosphorus content: ≥ 10.5% by weight
“As deposited” hardness: 500-600 HV
Hardness after heat treatment: up to about 1000 HV
Deposit structure: amorphous
Salt spray resistance (ASTM B117, 30 µm): >1,000 hours
Non-toxicity: compliant with NSF Standard 51 (food contact)
Reference standards: ASTM B733 (Type V), ASTM B117, ISO 4527,
NSF Standard 51, NACE

Reference standards

The Deltar ENP 1012 process is qualified according to the main international standards:

ASTM B733 – Standard specification for autocatalytic nickel-phosphorus deposits
ASTM B117 – Salt spray corrosion resistance test
ASTM B656 – Surface preparation for autocatalytic deposition
ASTM B571 – Adhesion test
ISO 4527 – Autocatalytic nickel-phosphorus deposits,
specifications and test methods
MIL-C-26074 – Military specification for autocatalytic
nickel coatings
NSF Standard 51 – Materials in contact with food

What is needed for a quick assessment

Technical drawing with areas to be treated and to be protected
Type of base material (steel, stainless, aluminium, duplex, superalloy)
Operating environment (chemical, corrosive, marine, food)
Required thickness
Applicable specifications (ASTM, ISO, NACE, customer)
Any required post-deposition heat treatment

High-phosphorus electroless nickel plating (ENP 1012)

Maximum anti-corrosion protection for critical environments