Effect of Annealing on Temperature Coefficient of Resistance of Cu-Ni Foil as Strain Gauge Material

Near zero Temperature Coefficient of Resistance (TCR) is an increasing concern in the strain gauge manufacturing industry. The purpose of this study is to investigate the connection between the TCR of the Strain Gauge (SG) and the annealing temperature of the foil used to manufacture the strain gauge. Constantan foils were heat treated, under a nonoxidizing annealing environment. The TCR of the manufactured foil-strain gauges were calculated in the range of -$10^{\circ}\mathrm{C}$ to $40^{\circ}\mathrm{C}$. The TCR values were shifted from negative to positive with annealing temperature. This study provides a conclusive response to the question concerning the effect of annealing temperature of Constantan foil for the manufacturing of strain gauges with near zero TCR.