Silver-Nickel Contact Materials


OVERVIEW

Silver-nickel contact materials are used typically in low and medium power applications. Switches, mini-relays and low power contactors are typical applications for silver-nickel. There is some use of silver-nickel in AC circuit breakers. Contact resistances are relatively low and remain stable over time when compared to silver-copper alloys. As the nickel content increases, the contact resistance increases. The increase in the nickel content also improves the materials resistance to arc erosion. One disadvantage of silver-nickel is its diminishing arc erosion properties over 100 amps.

AVAILABILITY

Silver-nickels are produced through powder metallurgy processes. Compositions for these materials range from 5% nickel to 30% nickel. The lower concentrations of nickel can be manufactured into strip and wire products for further fabrication into contact rivets, clad products and discrete contacts. The materials with the higher nickel concentrations are produced as discrete contacts, through unit compaction processes. The discrete contacts are often supplied with braze alloy flushed to the brazing face. 

MATERIALS

Composition

Hardness

Density

Conductivity

(weight %)

(R'well)

(g/cc)

(IACS %)

Silver-Nickel

WN51 Ag95/Ni5

F 32*

10.3

94

WN101 Ag90/Ni10

F35*

10.2

87

WN151 Ag85/Ni15

F40*

10.1

80

SN15PSR Ag85/Ni15

F50*

10.0

68

SN30PSR Ag70/Ni30

F42*

9.6

55



Note
The asterisk (*) indicates the fully annealed condition. The compositions listed are generally considered the industry standards. The values listed above represent the typical average properties of the materials. Modifications to meet special applications may be possible.