References cited in this section

2. G.G. Gawrilov, Chemical (Electroless) Nickel Plating, Portcullis Press, Redhill, England, 1979

49. Metals Handbook, 9th ed., Vol 1, American Society for Metals, 1978

50. "Autocatalytic Nickel-Phosphorus Coatings," ISO 4527, International Standards Organization Applications

Electroless nickel is applied for five different applications: corrosion resistance, wear resistance, lubricity, solderability, or buildup of worn or overmachined surfaces. To varying degrees, these properties are used by all segments of industry, either separately or in combination. Applications of these coating are given in Table 11.

Table 11 Applications of electroless nickel plating

Application

Base metal

Coating thickness(a)

Reason for use

fini

mils

Automotive

Heat sinks

Aluminum

10

0.4

Corrosion resistance, solderability, uniformity

Carburetor components

Steel

15

0.6

Corrosion resistance

Fuel injectors

Steel

25

1.0

Corrosion and wear resistance

Ball studs

Steel

25(b)

1.0(b)

Wear resistance

Differential pinion ball shafts

Steel

25(b)

1.0(b)

Wear resistance

Disc brake pistons and pad holders

Steel

25(b)

1.0(b)

Wear resistance

Transmission thrust washers

Steel

25(b)

1.0(b)

Wear resistance

Syncromesh gears

Brass

30

1.2

Wear resistance

Knuckle pins

Steel

38(b)

1.0®

Wear resistance

Exhaust manifolds and pipes and mufflers

Steel

25

1.0

Corrosion resistance

Shock absorbers

Steel

10

0.4

Corrosion resistance and lubricity

Lock components

Steel

10

0.4

Wear and corrosion resistance and lubricity

Hose couplings

Steel

5

0.2

Wear and corrosion resistance

Gears and gear assemblies

Carburized steel

25(c)

1.0(c)

Buildup of worn surfaces and wear resistance

Fuel pump motors

Steel

12

0.5

Corrosion, wear resistance

Aluminum wheels

Aluminum

25

1

Corrosion resistance

Water pump components

Steel

20

0.8

Corrosion resistance

Application

Base metal

Coating thickness(a)

Reason for use

fini

mils

Steering column tilt wheel components

Powdered metal

15

0.6

Ease of movement

Air bag hardware

Steel

10

0.4

Ease of movement

Air conditioning compressor components

Steel

25

1

Low friction

Decorative plastics

Plastics (ABS, etc)

2

0.1

Base coat

Slip yokes

Steel

15

0.6

Aircraft/aerospace

Bearing journals

Aluminum

38(d)

1.5(d)

Wear resistance and uniformity

Servo valves

Steel

18

0.7

Corrosion resistance, uniformity and lubricity

Compressor blades

Alloy steel

25(e)

1.0(e)

Hot zone hardware

Alloy steel

25

1.0

Corrosion and wear resistance

Piston heads

Aluminum

25

1.0

Wear resistance

Engine main shafts and propellers

Steel

>38

>1.5

Buildup of worn surfaces and wear resistance

Hydraulic actuator splines

Steel

25(b)

1.0®

Wear resistance

Seal snaps and spacers

Steel

20(e)

0.8(e)

Wear and corrosion resistance

Landing gear components

Aluminum

>125

>5.0

Buildup of mis-machined surfaces

Struts

Stainless steel

>25

>1.0

Buildup of mis-machined or worn surfaces

Pitot tubes

Brass/stainless steel

12

0.5

Corrosion and wear resistance

Gyro parts

Steel

12

0.5

Wear resistance and lubricity

Application

Base metal

Coating thickness(a)

Reason for use

fini

mils

Engine mounts

4140 Steel

25

1.0

Wear and corrosion resistance

Oil nozzle components

Steel

25

1.0

Corrosion resistance and uniformity

Turbine front bearing cages

Alloy steel

25

1

Corrosion, wear resistance

Engine mount insulator housing

Alloy steel

25

1

Corrosion resistance

Flanges

Alloy steel

20

0.8

Corrosion, wear resistance

Sun gears

Alloy steel

25

1

Wear resistance

Breech caps

Alloy steel

15

0.6

Corrosion, wear resistance

Shear bolts

Alloy steel

50

2

Corrosion resistance

Engine oil feed tubes

Steel, stainless steel

10

0.4

Corrosion resistance

Flexible bearing supports

Steel

25

1

Corrosion resistance

Break attach bolts

Alloy steel

25

1

Corrosion resistance

Antirotational plates

Alloy steel

25

1

Wear resistance

Wing flap universal joints

Alloy steel

20

0.8

Corrosion, low friction

Titanium thruster tracks

Titanium

25

1

Wear and corrosion resistance, low friction

Printing

Printing rolls

Steel/cast iron

38

1.5

Corrosion and wear resistance

Press beds

Steel/cast iron

38

1.5

Corrosion and wear resistance

Textiles

Application

Base metal

Coating thickness(a)

Reason for use

fini

mils

Feeds and guides

Steel

50(b)

2.0(b)

Wear resistance

Fabric knives

Steel

12(b)

0.5(b)

Wear resistance

Spinnerettes

Stainless steel

25

1.0

Corrosion and wear resistance

Loom ratchets

Aluminum

25

1.0

Wear resistance

Knitting needles

Steel

12

0.5

Wear resistance

Molds and dies

Zinc die cast dies

Alloy steel

25

1.0

Wear resistance and part release

Glass molds

Steel

50

2.0

Wear resistance and part release

Plastic injection molds

Alloy steel

15

0.6

Corrosion and wear resistance and part release

Plastic extrusion dies

Alloy steel

25

1.0

Corrosion and wear resistance and part release

Military

Fuse assemblies

Steel

12

0.5

Corrosion resistance

Mortar detonators

Steel

10

0.4

Corrosion resistance

Tank turret bearings

Alloy steel

30

1.2

Wear and corrosion resistance

Radar wave guides

Aluminum

25

1.0

Corrosion resistance and uniformity

Mirrors

Aluminum/beryllium

>75

>3.0

Uniformity and reflectivity

Firearms

Commercial and military firearms

Steel

s

0.3

Corrosion and wear resistance and lubricity

Application

Base metal

Coating thickness(a)

Reason for use

fini

mils

Marine

Marine hardware

Brass

25

1.0

Corrosion resistance

Pumps and equipment

Steel/cast iron

50

2.0

Corrosion and wear resistance

Electronics

Heat sinks

Aluminum

10

0.4

Corrosion resistance and solderability

Computer drive mechanisms

Aluminum

18

0.7

Corrosion and wear resistance

Memory drums and discs

Aluminum

25

1.0

Corrosion and wear resistance and uniformity

Terminals and lead wires

Alloy steel

2

0.1

Solderability

Chassis

Aluminum/steel

12

0.5

Corrosion resistance and solderability

Connectors

Steel/aluminum

25

1.0

Corrosion and wear resistance and solderability

Diode and transistor cans

Steel

5

0.2

Corrosion resistance and solderability

Interlocks

Steel/brass

12

0.5

Corrosion and wear resistance

Junction fittings

Aluminum/plastic

10

0.4

Corrosion and wear resistance, solderability and conductivity

Printed circuit boards

Plastic

5

0.2

Solderability and weldability

Railroad

Tank cars

Steel

90(f)

3.5®

Corrosion resistance

Diesel engine shafts

Steel

>25

>1.0

Wear and fretting resistance and buildup of worn surfaces

Car hardware

Powder iron

20

0.8

Corrosion and wear resistance

Application

Base metal

Coating thickness(a)

Reason for use

Hill

mils

Electrical

Motor shafts

Steel

12

0.5

Wear and corrosion resistance

Rotor blades

Steel/aluminum

25(b)

1.0(b)

Wear and corrosion resistance

Stator rings

Steel/aluminum

25

1.0

Wear and corrosion resistance

Chemical and petroleum

Pressure vessels

Steel

50

2.0

Corrosion resistance

Reactors

Steel

100®

4.0®

Corrosion resistance and product purity

Mixer shafts

Steel

38

1.5

Corrosion resistance

Pumps and impellers

Cast iron/steel

75

3.0

Corrosion and erosion resistance

Heat exchangers

Steel

75

3.0

Corrosion resistance

Filters and components

Steel

25

1.0

Corrosion and erosion resistance

Turbine blades and rotor assemblies

Steel

75

3.0

Corrosion and erosion resistance

Compressor blades and impellers

Steel/aluminum

125(d)

5.0(d)

Corrosion and erosion resistance

Spray nozzles

Brass/steel

12

0.5

Corrosion and wear resistance

Ball, gate, plug, check and butterfly valves

Steel

75

3.0

Corrosion resistance and lubricity

Valves

Stainless steel

25(b)

1.0®

Wear and galling resistance and protection against stress-corrosion cracking

Chokes and control valves

Steel/stainless steel

75

3.0

Corrosion and wear resistance and protection against stress-corrosion cracking

Application

Base metal

Coating thickness(a)

Reason for use

Hill

mils

Oil field tools

Steel

75

3.0

Corrosion and wear resistance

Oil well packers and equipment

Alloy steel

75

3.0

Corrosion and erosion resistance

Oil well tubing and pumps

Steel

50

2.0

Corrosion and wear resistance

Drilling mud pumps

Alloy steel

75

3.0

Corrosion resistance and protection against stress-corrosion cracking

Hydraulic systems and actuators

Steel

75

3.0

Corrosion and wear resistance and lubricity

Blowout preventers

Alloy steel

75

3.0

Corrosion and wear resistance

Medical and pharmaceutical®

Disposable surgical instruments and equipment

Steel/aluminum

12

0.5

Corrosion resistance and ease of operation

Sizing screens

Steel

20

0.8

Corrosion resistance and cleanliness

Pill sorters

Steel

20

0.8

Corrosion resistance and cleanliness

Feed screws and extruders

Steel

25

1.0

Corrosion and wear resistance and cleanliness

Food(g)

Pneumatic canning machinery

Steel

25

1.0

Corrosion and wear resistance and cleanliness

Baking pans

Steel

25

1.0

High temperature resistance, cleanliness, and ease of release

Molds

Steel

12

0.5

Cleanliness, corrosion resistance and ease of release

Grills and fryers

Steel

12

0.5

Cleanliness, corrosion resistance and ease of release

Mixing bowls

Steel

25

1.0

Cleanliness and corrosion and wear resistance

Application

Base metal

Coating thickness(a)

Reason for use

Hill

mils

Bun warmers

Steel

12

0.5

Cleanliness and ease of release

Feed screws and extruders

Steel

25

1.0

Cleanliness and corrosion and wear resistance

Material handling

Hydraulic cylinders and shafts

Steel

25

1.0

Corrosion and wear resistance and lubricity

Extruders

Alloy steel

75(b)

3.0(b)

Wear and corrosion resistance

Link drive belts

Steel

12

0.5

Wear and corrosion resistance and lubricity

Gears and clutches

Steel

>25

>1.0

Wear resistance and buildup of worn surfaces

Mining

Hydraulic systems

Steel

60

2.4

Corrosion and abrasion resistance

Jetting pump heads

Steel

60

2.4

Corrosion and erosion resistance

Mine engine components

Steel/cast iron

30

1.2

Corrosion and wear resistance

Piping connections

Steel

60

2.4

Corrosion resistance

Framing hardware

Steel

30

1.2

Corrosion resistance

Wood and paper

Knife holder corer plates

Steel

30

1.2

Corrosion and abrasion resistance

Abrading plates

Steel

30

1.2

Corrosion and abrasion resistance

Chopping machine parts

Steel

30

1.2

Corrosion and abrasion resistance

Miscellaneous

Application

Base metal

Coating thickness(a)

Reason for use

fim

mils

Chain saw engines

Aluminum

25

1.0

Wear and corrosion resistance

Drill and taps

Alloy steel

12(b)

0.5(b)

Wear resistance and ease of use

Precision tools

Alloy steel

12

0.5

Wear resistance and cleanliness

Shaver blades and heads

Steel

S

0.3

Wear resistance and smoothness

Pen tips

Brass

5

0.2

Corrosion resistance

(a) Many components are heat treated at 190 to 210 °C (375 to 410 °F) for 1 to 3 h to improve adhesion or to relieve hydrogen embrittlement.

(b) Heat treated for 1 h at 400 °C (750 °F) for maximum hardness.

(c) Heat treated for 6 h at 135 °C (275 °F) for hydrogen embrittlement relief.

(d) Heat treated for 10 h at 290 °C (550 °F) for maximum hardness.

(e) Cadmium plated after electroless nickel and then heat treated for 2 h at 340 °C (640 °F) to diffuse cadmium into the nickel.

(f) Heat treated for 1 h at 620 °C (1150 °F) to diffuse coating into basis metal.

(g) For medical, pharmaceutical, and food applications, coatings must be free of toxic heavy metals such as lead, cadmium, mercury, or thallium.

Applications for electroless nickel-boron deposits in the electronics industry include wire bonding for IC chips, soldering, brazing, laser welding, low electrical resistivity, and as a diffusion barrier.

0 0

Post a comment