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EMI Shielding, EMI Gaskets


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EMI Shielding Materials

Many variations of shielding materials are available from National Power & Signal, the primary focus however for our products is the enclosure, cabinet or housing that requires an EMI gasket that can also act as an environmental seal. Following is a data sheet outlining the specific properties and technical information of the Nickel Graphite in Silicone elastomer material. Also shown is the technical data on the electrically conductive pressure sensitive adhesive or PSA.

 

Product: Silicone base with Nickel Graphite (Ni/g) conductive filler

 

Electrical Properties

Unit

Tolerance

Value

Volume Resistivity

Ohm-cm

Max.

0.040

Shielding Effectiveness 20MHz - 10GHz (E-Field)

dB

Min.

90

Physical Properties

 

 

 

Durometer (Hardness)

Shore A

+/- 7

75

Specific Gravity

23/23 deg C.

+/- 13%

2.7-3.3

Tensile Strength

PSI

Min.

270

Elongation

%

Min/Max

250

Tear Strength

PPI

Min.

35

Temperature

deg C.

Min/Max

-65/+200


Product: PSA, Conductive

 

Properties

Unit

Peel Adhesion

70 oz/in width (ult.)

19.8N/2.5cm

Shear Strength

2.2 psi indefinite

15.2 kPa

Elongation

N/A

Tensile Strength

N/A

Temperature Range

34 deg C / 107 deg C

Electrical Resistance (*1)

0.005 ohms/sq

Shelf Life (*2)

1 yr

Storage Temperature

23 deg C

R.H.

50%

 

All of the electrically conductive silicone elastomer compounds are available in sheet form ranging from .020” to .125” in thickness and sheet sizes that are


10”X 10” 12”X 12” 12”X 18” and 15”X 20”.

Standard Sheet Sizes
 

Thickness

Sheet Size

.020”

10”X 10”

.032”

10”X 10”

.062”

10”X 10”

Tolerance +/- .006”

.093”

10”X 10”

.125”

10”X 10”

.020”

12”X 12”

.032”

12”X 12”

.062”

12”X 12”

Tolerance +/- .007

.093”

12”X 12”

.125”

12”X 12”

.020”

12”X 18”

.027”

12”X 18”

.030”

12”X 18”

.032”

12”X 18”

.040”

12”X 18”

Tolerance +/- .010

.047”

12”X 18”

.060”

12”X 18”

.062”

12”X 18”

.093”

12”X 18”

.125”

12”X 18”

Standard Sheet Sizes

 

.020”

15”X 20”

.032”

15”X 20”

.062”

15”X 20”

Tolerance +/- .010

.093”

15”X 20”

.125”

15”X 20”

 

The electrically conductive compounds can also be extruded, several standard shapes are available including solid round profiles and hollow profiles.
 

Solid Round Extruded

Dia

Hollow Round

OD

Extruded

ID

.040”

.070”

.025”

.053”

.093”

.035”

.062”

.103”

.040”

.070”

.125”

.045”

.080”

.125”

.062”

.093”

.156”

.050”

.103”

.177”

.079”

.112”

.250”

.125”

.125”

.312”

.192”

.130”

.375”

.250”

.150”

.437”

.250”

.160”

For a listing of additional profile shapes or for information on a custom extrusion profile contact National Power & Signal.

.188”

.216”

.250”

 

 

 

 

 

 

Custom die cut Nickel Graphite in silicone gasket with PSA. Also shown is Nickel Graphite in silicone in rolls and sheets.
 

 

 

 

 

 

 

 

 

 

 

Custom die cut Nickel Graphite in silicone gasket without PSA. Approximate size 2.00”X 1.75” material thickness .062” for small rf transmitter enclosure.
 

 

 

 

 

 

 

 

 

 

 

 

Custom die cut Nickel Graphite in silicone gasket with PSA.

 

 

 

 

 

 

 

 

National Power & Signal also manufactures EMI gaskets using oriented wire in silicone. This type of gasket material provides excellent conductivity from the main body of the enclosure or cabinet to the door or entry system of the design. The silicone elastomer is available in a solid or sponge, provides good environmental protection and is very economical to use in most industrial shielding applications.


This gasket material is also available with a pressure sensitive adhesive. Following is technical data on the oriented wires in silicone.
 

 

SOLID SILICONE

FLUOROSILICONE

Shielding dB 200 KHz

70

70

70

70

70

85

100 MHz

125

100

130

125

100

130

1.0 GHz

125

100

130

125

100

125

Fuel/Chem Resistant

NO

NO

NO

YES

YES

YES

Closing Force (psi)

25-90

25-90

25-90

25-90

25-90

25-90

Compression Set (%)

25

25

25

25

25

25

Temp Range ( C )

-60/200

-60/200

-60/200

-55/200

-55/200

-55/200

Wire Count/ sq-in

900

900

900

900

900

900

Column

1

2

3

1

2

3


Shown are six different material configurations, the first three are in standard solid silicone and the last three are in fluorosilicone for applications requiring resistance to chemicals, fuels and solvents.

 

 

SILICONE SPONGE

Shielding dB 200 KHz

70

70

70

100 MHz

120

85

130

1.0 GHz

125

70

125

Fuel/Chem Resistant

NO

NO

NO

Closing Force (psi)

5-50

5-50

5-50

Temp Range ( C )

-60/200

-60/200

-60/200

Wire Count/ sq-in

650

650

650

Column

1

2

3


Shown are nine separate material specifications for solid silicone, fluorosilicone and silicone sponge. When choosing a material you must include all of the information provided in the specific column that is applicable to your design requirements. The same information can also be used to order samples and to produce a procurement specification.

 


Die cut oriented wire in silicone sponge gasket strips.



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