TABLE 397.— ELECTRICAL CONDUCTIVITY OF ALLOYS 391 



This table shows the conductivity of alloys and the variation of the conductivity with 

 temperature. The conductivity is given as C t = Co (1 — at -+- bt 2 ), and the range of tem^ 

 perature was from 0° to 100° C. 



The table is arranged in three groups to show (1) that certain metals when melted to- 

 gether produce a solution which has a conductivity equal to the mean of the conductivities 

 of the components, (2) the behavior of those metals alloyed with others, and (3) the be- 

 havior of the metals alloyed together. 



Part 1 



Weight % Volume % 



v v ' 



of first named ill 



Alloys , A v 10* o X 10" b X 10" 



Sn,Pb 77.04 83.96 



SruCd 82.41 83.10 



SnZn 78.06 77.71 



PbSn 64.13 53.41 



ZnCd 2 24.76 26.06 



SnCd 23.05 23.50 



CdPbe 7.37 10.57 



Part 2 



Volume % Weight % 



v 



of first named 

 Alloys t A . 



Lead-silver (PkoAg) ... 95.05 94.64 



Lead-silver (PbAg) .... 48.97 46.90 



Lead-silver (PbAg,) ... 32.44 30.64 



Tin-gold (Sn 12 Au) 77.94 90.32 



" " (Sn s Au) 59.54 79.54 



Tin-copper 92.24 93.57 



" 80.58 83.60 



" 12.49 14.91 



" 10.30 12.35 



" 9.67 11.61 



" 4.96 6.02 



" 1.15 1.41 



Tin-silver 91.30 96.52 



"' " -.. 53.85 75.51 



Zinc-copper 36.70 42.06 



" 25.00 29.45 



" 16.53 23.61 



" 8.89 10.88 



" 4.06 5.03 



Note. — Barus has pointed out that the temperature variation of platinum alloys contain- 



n 

 ing less than 10% of the other metal can be nearly expressed by an equation y = — — m, 



x 



where y is the temperature coefficient and x the specific resistance, m and n being constants. 

 If a be the temperature coefficient at 0°C and j the corresponding specific resistance, 

 s(a -\- m) =n 



For platinum alloys Barus's experiments gave m = — .000194 and n = .0378. 



For steel m — —.000303 and n = .0620. 

 Matthiessen's experiments reduced by Barus gave for 



Gold alloys m — —.000045, n = .00721. 



Silver " m = -.000112, n = .00538. 



Copper " m = —.000386, n = .00055. 



(continued) 



SMITHSONIAN PHYSICAL TABLES 



