Shanghai Autra Precision Surface Treatment Co., Ltd.

LOW PHOSPHORUS / ELECTROLESS NICKEL

Low-phosphorus electroless nickel

Low-temperature / ultra-low-P and low-P: two process groups, selected as needed.

Low-temperature low-P, ultra-low-P and extremely-low-P continuous types are grouped together for easy comparison around lower bath temperature or lower phosphorus content; the 1%–3% low-P option is shown as a separate group. Operating temperature and coating characteristics are listed for each product.

The following are product data and historical reference data, not guarantees for any workpiece; formal specifications are subject to engineer confirmation and the quotation.

Two process groups, each product's parameters compared separately

On mobile, swipe left and right; the first column keeps the comparison items.

Low-P series · coating characteristics & bath operating conditions
Selection parameterLow-temperature low-PUltra-low-PExtremely-low-P continuous typeLow-P
GroupLow-temp / ultra-low-P optionsLow-P option
Coating phosphorus content2±1%0.5%–1%Below 1% (continuous operation)1%–3%
Operating temperature75℃88–94℃83–87℃85–90℃
pH6.80±0.106.00±0.106.00±0.106.40±0.10
Nickel plating rate14±2 μm/h (fresh bath, 75℃)10±2 μm/h (fresh bath, 90℃)11±2 μm/h (at make-up, 85℃)17±2 μm/h (fresh bath, 87℃)
Coating hardnessHV 600 or above achievable (without heat treatment)HV 700 (after electroless plating)—HV 650 (after electroless plating)

Plating rates come from fresh-bath conditions at different temperatures for each version and do not represent a performance ranking under the same conditions. First choose the required process, then check temperature, coating composition and heat treatment state; these values cannot be used directly as acceptance criteria for all workpieces.

01 / Selecting for lower bath temperature or lower phosphorus content

Low-temp / ultra-low-P options

This group contains three independent processes. The low-temperature low-P type operates at 75℃; the ultra-low-P and extremely-low-P continuous types operate at 88–94℃ and 83–87℃ respectively, chosen according to coating composition and production line conditions.

Silver precision frames and stepped sleeves on a dark gray background; visual illustration of the low-temperature low-P product
AI-generated visual illustration of precision metal parts; not an actual product photo or performance test image.

01 / 75℃ low-temperature process, combining low P with wear resistance.

Low-temperature low-P

Lead-free electroless nickel bath

This is a lead-free low-temperature low-P electroless nickel bath that can continuously perform Ni-P electroless plating at 75℃, with a coating phosphorus content of 2±1%. Coating hardness without heat treatment can reach HV 600 or above, along with good wear resistance, low volume resistivity and magnetic coating characteristics. Suited to process selection focused on lower operating temperature and low-P coating performance, and compatible with automatic analysis and replenishment for bath management.

Lower operating temperature

The manual specifies an operating temperature of 75℃, offering an option for processes that care about lower bath temperature.

As-plated hardness & wear resistance

Coating hardness without heat treatment can reach HV 600 or above, with good wear resistance.

Suited to continuous management

Supports automatic analysis and replenishment, helping maintain bath conditions and stable quality.

Process parameters

Coating phosphorus content
2±1%Instructions p.3
Operating temperature
75℃Manual operating conditions
pH
6.80±0.10
Nickel plating rate
14±2 μm/hFresh bath, 75℃
Nickel sulfate concentration
24.0±2 g/Las NiSO₄·6H₂O
Bath load ratio V/A
8–20bath volume mL / workpiece surface area cm²
Coating hardness
HV 600 or above achievablewithout heat treatment

Application directions & confirmation conditions

Selection based on typical uses of low-P coatings combined with a lower bath temperature.

Molds & forming tooling

Molds · plungers · precision tooling

Workpieces that need as-plated hardness and surface wear resistance, and where production at a lower bath temperature is desired, can evaluate this low-temperature process.

Suitability of low-temperature conditions must be confirmed with substrate and pretreatment.

Valves & precision transmission

Valve parts · gearbox components

For wear resistance needs on moving mating surfaces, trial plating selection can combine industry uses of low-P coatings with this product's 75℃ process conditions.

Coating thickness and fit tolerances must be checked at the same time.

Electronic connectors

Connectors · electronic terminals

Connectors requiring low volume resistivity and coating hardness can be included in application evaluation; assembly reliability should be tested with the connection structure.

Verify around contact resistance, connection method and service environment.

The instructions state: without heat treatment, coating hardness can reach HV 600 or above. The continuous test chart on p.9 of the technical data shows about HV 650, a test reference value, not a guaranteed value.

The above directions combine industry uses of low-P coatings with this product's 75℃ process features; specific substrates and workpieces must be evaluated by trial plating.

Precisely arranged silver metal pins and micro sleeves on a dark gray background; visual illustration of the ultra-low-P product
AI-generated visual illustration of precision metal parts; not an actual product photo or performance test image.

02 / 0.5%–1% coating phosphorus, for lower-P process needs.

Ultra-low-P

Lead-free electroless nickel bath

This is a lead-free ultra-low-P electroless nickel bath with 0.5%–1% coating phosphorus and HV 700 hardness after plating, combining wear resistance, low volume resistivity and magnetic coating characteristics. Application evaluation can focus on low-P requirements for parts such as precision connectors and moving mating parts, with continuous production managed by automatic analysis and replenishment.

Focus on ultra-low-P coatings

Coating phosphorus content of 0.5%–1%, a dedicated version for lower phosphorus requirements.

HV 700 hardness after plating

Combining wear resistance, low volume resistivity and magnetic characteristics to meet functional surface treatment needs.

Supports continuous production

Compatible with automatic analysis and replenishment, easing bath management per this version's process conditions.

Process parameters

Coating phosphorus content
0.5%–1%Interim instructions p.3
Operating temperature
88–94℃Per the manual's operating conditions table
pH
6.00±0.10
Nickel plating rate
10±2 μm/hFresh bath, 90℃
Nickel sulfate concentration
20.0±1.0 g/Las NiSO₄·6H₂O
Bath load ratio V/A
8–20bath volume mL / workpiece surface area cm²
Coating hardness
HV 700after electroless plating

Application directions & confirmation conditions

An option for lower phosphorus requirements; below are application directions suitable for verification.

Precision electronic connections

Connectors · terminals · electrical contact structures

Where lower coating phosphorus is explicitly required, this product can be evaluated together with low-resistance needs; contact resistance, soldering and assembly performance must be verified.

Refers to industry uses of low-P coatings; does not mean the ultra-low-P version has completed the same verification.

High-hardness moving mating parts

Valve parts · precision transmission components

For parts with requirements on both composition and as-plated hardness, coating options for wear and mating surfaces can be evaluated around the HV 700 hardness after plating.

Confirm suitability by actual load, friction pair and thickness.

New-energy electrical connections

Busbars · battery connectors

Low-P electroless nickel already has industry uses of this kind. If a design specifies 0.5%–1% phosphorus content, this product can be included in process verification.

Electrical connection, thermal cycling and service environment requirements must be verified.

Hardness uses the latest confirmed value of HV 700; other operating conditions refer to the August 2025 rev.0 technical manual.

Application directions refer to industry data on low-P coatings; suitability of the 0.5%–1% ultra-low-P version must be verified on the specific workpiece.

NI-P / Extremely-low-P continuous production

Coating composition & management features

Coating system
Nickel-phosphorus (Ni-P)
Coating phosphorus content
Below 1%Phosphorus content remains essentially stable as turnovers increase
Chemical features
Lead-free
Production management
Automatic analysis · automatic replenishment

03 / Continuous operation, maintaining an extremely-low-P coating.

Extremely-low-P continuous type

Lead-free electroless nickel bath

The extremely-low-P continuous type can continuously form Ni-P coatings with phosphorus below 1%, and coating phosphorus remains essentially stable as turnovers increase. Its lead-free system suits automatic analysis and replenishment, easing bath management in continuous production. Operating temperature is 83–87℃; at make-up at 85℃, the plating rate is 11±2 μm/h.

Extremely low P maintained continuously

The instructions state that coating phosphorus remains essentially stable below 1% as turnovers increase.

Lead-free bath system

Forms extremely-low-P Ni-P coatings with a lead-free electroless nickel bath, suited to process management for continuous production.

Automatic analysis & replenishment

Suitable for automatic analysis and replenishment, helping maintain stable quality in continuous operation.

Process parameters

Coating phosphorus content
Below 1%continuous operation; extremely-low-P continuous type instructions p.1
Operating temperature
83–87℃Raise temperature as turnovers increase to manage plating rate
pH
6.00±0.10
Nickel plating rate
11±2 μm/hat make-up, 85℃
Nickel sulfate concentration
20.0±2.0 g/Las NiSO₄·6H₂O
Bath load ratio V/A
8–12bath volume mL / workpiece surface area cm²

Selection focus & production conditions

Confirm the process per the extremely-low-P continuous type instructions, around the extremely-low-P coating target and continuous production conditions.

Extremely-low-P composition requirement

Ni-P · phosphorus below 1%

For process evaluation aiming to continuously obtain extremely-low-P Ni-P coatings; the instructions explicitly stress phosphorus stability as turnovers increase.

Continuous operation & rate management

83–87℃ · automatic analysis & replenishment

The reference condition for plating rate is 85℃ at make-up. The instructions require raising temperature within the operating range as turnovers increase to manage the nickel plating rate.

Parameters are based on pp.1 and 3 (PDF pp.3 and 5) of the "Extremely-low-P continuous type instructions" (2023.05). Phosphorus content keeps the original wording "below 1%"; the rate is data at make-up at 85℃.

Coating hardness and specific workpiece performance must be confirmed separately according to the actual process of the extremely-low-P continuous type.

02 / Selecting for wear resistance and precision fit

Low-P option

Coating phosphorus content is 1%–3% and operating temperature 85–90℃. Process evaluation centers on as-plated hardness, wear resistance and the fit requirements of specific parts.

Silver gears, precision rollers and sleeves on a dark gray background; visual illustration of the general-purpose low-P product
AI-generated visual illustration of precision metal parts; not an actual product photo or performance test image.

04 / 1%–3% low-P coating, chosen for wear resistance and precision fit.

Low-P

Lead-free electroless nickel bath

This is a lead-free low-P electroless nickel bath with 1%–3% coating phosphorus and HV 650 hardness after plating, combining wear resistance, low volume resistivity and magnetic characteristics. It can be selected for applications such as mold tooling, valves, transmission components and hydraulic/pneumatic parts. Operating temperature is 85–90℃; it supports automatic analysis and replenishment for easy bath management in continuous production.

Supports production takt

At make-up at 87℃, the manual indicates a nickel plating rate of 17±2 μm/h.

HV 650 hardness after plating

Combined with wear resistance and low volume resistivity, a low-P coating option for functional parts.

Continuous bath management

Supports automatic analysis and replenishment, helping maintain bath conditions and stable quality.

Process parameters

Coating phosphorus content
1%–3%coating phosphorus content
Operating temperature
85–90℃manual operating conditions
pH
6.40±0.10
Nickel plating rate
17±2 μm/hfresh bath, 87℃
Nickel sulfate concentration
24.0±2.0 g/Las NiSO₄·6H₂O
Bath load ratio V/A
8–20bath volume mL / workpiece surface area cm²
Coating hardness
HV 650after electroless plating

Application directions & confirmation conditions

Learn the typical application directions of low-P coatings around specific parts and functional needs.

Molds & forming tooling

Molds · plungers · tooling

For areas subject to repeated forming and contact wear, selection focuses on as-plated hardness and wear resistance. Public industry data lists related uses of low-P coatings.

The solution should be confirmed with workpiece shape, thickness and surface precision.

Valves & motion mechanisms

Valve parts · gearbox components · hydraulic/pneumatic parts

For surfaces with frequent motion and precision fit, the hardness and wear performance of low-P coatings can be evaluated while controlling coating thickness.

Confirm by trial plating against load, media and fit tolerances.

Electronic & electrical connections

Connectors · terminals · busbars · battery connectors

For low-resistance and assembly needs of electrical connection parts, a low-P nickel layer and suitable thickness can be selected together with the substrate and subsequent connection method.

Solderability and connection reliability must be confirmed in the actual structure.

Application scenarios refer to low-P electroless nickel industry data; specific thickness, fit dimensions and service conditions must be confirmed with the workpiece.

Ni-P part application data

Starting from actual parts, learn about Ni-P electroless nickel applications in automotive and precision machinery.

The following Ni-P electroless nickel case images help explain part application needs and do not correspond directly to the four chemicals on this page. Specific selection must be confirmed with the substrate, target performance and process conditions.

AUTRA clutch hub case image

Automotive transmission

Clutch hub

Used in manual transmission mechanisms, balancing sliding properties and wear resistance.

See application conditions ↗
AUTRA image of the fuel control device using the roller bracket

Fuel injection control

Roller bracket

Used in engine fuel injection control devices, focusing on wear resistance, rust prevention and dimensional accuracy.

See application conditions ↗
Technical data & application reference notes

Phosphorus content listed refers to coating phosphorus content. Parameters are compiled from product manuals and the latest confirmed information; actual performance depends on substrate, pretreatment, coating thickness and bath management.

Product parameters are compiled from the corresponding instructions and confirmed values; industry applications are selection directions and do not mean this series has been verified on all listed workpieces. Corresponding process data can be requested at the end of the page.

Data for the extremely-low-P continuous type is based on the "Extremely-low-P continuous type instructions" (2023.05): PDF p.3 (text p.1) lists the extremely-low-P, lead-free and automatic analysis/replenishment features, and PDF p.5 (text p.3) lists the operating conditions. Each product's parameters are listed separately for its process.

Confirm a low-P electroless nickel solution with an engineer

For chemical selection, please provide the substrate, target performance and line conditions; for parts plating, also specify quantity and drawing requirements.