website created and maintained by joris kraak           

 

 

 

 

       Coatings - elektrical conductivity or resistivity

 

 

Thermally sprayed coatings with a low electrical conductivity are used to restore electrical contact pads or as a conductor on a surface which doesn't have the electrical properties needed.

Applications like these have certain basic rules:

  1. Generally the electrical conductivity will decrease when temperature increases
  2. The electrical conductivity of a metal is expressed in electrical resistance (table.1)
  3. Thermally sprayed coatings have, because of their typical lamellar structure, a lower electrical conductivity than the same metal forged
  4. Thermally sprayed coatings with a low level of oxide inclusions and porosity possess the highest electrical conductivity.
  5. Stress relieve can improve the electrical conductivity of a thermally sprayed coating.
 
Resistance Ohm.m (10-8)
 Point of fusion °C Density g/cc Heat conduction Cal/cm/°C/sec.
         
Silver 1.6 960 10.4 0.97
Copper 1.7 1083 8.9 0.92
Aluminium 2.7 660 2.7 0.5
Zinc 6 420 7.1 0.27
Tin 11 232 7.3 0.16
Chromium 13 1860 7.2 0.17
Lead 21 327 11.4 0.08
Wolframcarbide 53 2600 15.5 0.07
Nickel 7 1460 8.5 0.15
Aluminiumoxide 1020 2050 3.9 0.1

 

 

 

 

 

 

 

 

 

 

 

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