SILVER PLATING
Silver is a precious metal . Requirement of Silver plating come maximum from electronics industry and jewellary industry . In electronic industry silver plating is more prefereble because silver has highest electrical conductivity compared to all other metals. Silver have excellent solderability.
Silver plating have three types of finish in the terms of appearance :
1. Matt
2. Semi bright and
3. Bright.
For electronic Industry matt and semi bright finish is more suitable because bright finish conductivity can be reduce due to organic brighteners in the plating bath.
For Jewellary industry silver plating is decorative purpose so they need mirror type bright finish.
At Present, Maximum silver plating done by cyanide base process. Slowly Non- cyanide silver plating introducing in the market by some manufacturers like epi .
Silver plating process :
1. Pretreatment process ( Depend on base metal like copper, aluminium, brass etc)
2. Undercoat coating ( optional)
3. Silver strike
4. Silver plating
5. Anti Tarnish coating
Quality Control :
1. Physical appearance Inspection
2. Adhesion Test by Adhesive tape
3. Thickness test by thickness tester
4. Anti Tarnish Test
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ELECTROLESS NICKEL
Silver is a precious metal . Requirement of Silver plating come maximum from electronics industry and jewellary industry . In electronic industry silver plating is more prefereble because silver has highest electrical conductivity compared to all other metals. Silver have excellent solderability.
Silver plating have three types of finish in the terms of appearance :
1. Matt
2. Semi bright and
3. Bright.
For electronic Industry matt and semi bright finish is more suitable because bright finish conductivity can be reduce due to organic brighteners in the plating bath.
For Jewellary industry silver plating is decorative purpose so they need mirror type bright finish.
At Present, Maximum silver plating done by cyanide base process. Slowly Non- cyanide silver plating introducing in the market by some manufacturers like epi .
Silver plating process :
1. Pretreatment process ( Depend on base metal like copper, aluminium, brass etc)
2. Undercoat coating ( optional)
3. Silver strike
4. Silver plating
5. Anti Tarnish coating
Quality Control :
1. Physical appearance Inspection
2. Adhesion Test by Adhesive tape
3. Thickness test by thickness tester
4. Anti Tarnish Test
SILVER ANTI TARNISH TEST PROCEDURE :
Take 1 ml of 20- 24 % by weight ammonium or potassium
sulphide, mix the 1 ml ammonium sulphide solution In 1 litre D M water.
Take the 1 drops solution from above 1 litre solutionand drop
on the silver plated component, upto 5 min surface should not be change to
brown or black.
CONDUCTIVITY OF VARIOUS METALS
Material
|
RESISTIVITY OHM PER METRE at 20 °C
|
CONDUCTIVITY SIEMENS PER METRE at 20 °C
|
|
Silver
|
1.59×10−8
|
6.30×107
|
|
Copper
|
1.68×10−8
|
5.96×107
|
|
Annealed copper
|
1.72×10−8
|
5.80×107
|
|
Gold
|
2.44×10−8
|
4.10×107
|
|
Aluminium
|
2.82×10−8
|
3.5×107
|
|
Tungsten
|
5.60×10−8
|
1.79×107
|
|
Zinc
|
5.90×10−8
|
1.69×107
|
|
Nickel
|
6.99×10−8
|
1.43×107
|
|
Lithium
|
9.28×10−8
|
1.08×107
|
|
Iron
|
1.0×10−7
|
1.00×107
|
|
Platinum
|
1.06×10−7
|
9.43×106
|
|
Tin
|
1.09×10−7
|
9.17×106
|
|
Carbon steel (1010)
|
1.43×10−7
|
6.99×106
|
|
Lead
|
2.2×10−7
|
4.55×106
|
|
Titanium
|
4.20×10−7
|
2.38×106
|
|
Stainless steel
|
6.9×10−7
|
1.45×106
|
|
Mercury
|
9.8×10−7
|
1.02×106
|
|
ELECTROLESS NICKEL
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