Selective Electroplating

What is Selective Electroplating?

Selective Electroplating also known as Brush Electroplating, Selective Electroplating or Electro Chemical Metalizing is a metal/alloy deposition method for localised electroplating without using an immersion tank system. (See http://en.wikipedia.org/wiki/Electroplating)

The process utilises an electrical current to deposit a desired material from a solution and bond it to a conductive object. A thin layer of material such as a metal or an alloy can thus be deposited upon the substrate surface. Surfaces liable to be plated may vary from cm² to m². The deposit thickness ranges from a few microns to several tenths of a millimetre.  (See Marlinec – Selective Electroplating.pdf)

Why use Selective Electroplating?

Selective Electroplating is primarily used for depositing a layer to bestow a desired property/characteristic to a surface that otherwise lacks that property.

Unique features of Selective Electroplating

  • It is fast
  • Can deposit hard metals (Rockwell C50 and above) at 25µm/minute.
  • Can deposit soft metals at up to 250µm/minute.
  • It is ideal for dimensional restoration.
  • It is portable which makes it ideal for field repairs or on assemblies.
  • It has excellent bond strength exceeding 97MPa (> 14 000 PSI).
  • A wide variety of metals, alloys and conversion coatings can be applied with the same equipment.

 

Benefits

  • Selective areas can be plated. No need for a tank system.
  • Excellent adhesion. Comply with numerous specifications throughout various industries.
  • No thermal distortion of any kind (cold process).
  • Wear and abrasion resistance.
  • Excellent thickness control.
  • Portability – onsite / in situ
  • Fast turnaround time
  • Cost effective
  • Dimensional restoration of original equipment manufacturer’s dimensions.
  • Practically no dimensional restriction to component size that can be plated.
  • Good corrosion resistance
  • Good lubricity
  • Exceptional hardness
  • Defect repairs
  • Anti-galling properties
  • Aesthetic qualities

 

Selective Electroplating vs Other Repair Methods

Criteria

Selective Electroplating

Welding

Metallizing

Electroplating

Precise Build-up Capability

Excellent

Poor

Poor

Fair to Good

Bond Quality

Excellent

Excellent

Fair to Good

Good

Thermal Distortion or Internal Stresses

None

Frequently

Sometimes

None

Density of Deposit (Porosity)

Very Dense*

Very dense but with blow holes

70-90% theoretical density

Dense

Portability

Yes

Yes

Sometimes

No

Need for Post Repair Machining or Grinding

Not required on deposits up to 0.025mm. on smooth surface

Always required

Most always required

Usually required

Hydrogen Embrittlement

No*

No

No

No

* Deposits are approximately 25% and 790% less porous than electroplated and metallized coatings respectively.

 

Plating Material Surface Hardness

Plating Deposit

Rockwell / Vickers
Hardness

Application

Cobalt Machinable

40Rc

Heavy metal build-up particularly in the repair of over machined parts.

Copper (heavy build alkaline)

21Rc

Fills pits and scores, repairs parts not subject to extreme heat or wear.

Nickel Acid High Build

50Rc

Build-up of over machined parts subject to wear and/or heat.

Nickel High Speed

46Rc

Build-up and resizing, worn or over machined parts.

Nickel Tungsten

63Rc

Hard wear resistant finish over other deposits.

Nickel Cobalt

43Rc

Build-up and resizing of parts subject to wear and above normal heat.

Cadmium

15-20Hv

Used for corrosion protection of aircraft parts on ultra-high strength steel.