Abstract
A fused-quartz dilatometer was used to measure the thermal-expansion coefficient α of nickel between 300 and 1000 K. Measurements on National Bureau of Standards certified copper and tungsten standards with the dilatometer established the uncertainty in the α measurements on nickel as ± 0.8% (±0.10 × 106 K1), except within ± 2 K of the Curie temperature TC where the uncertainty was about ± 1.6%. Results of 38 investigations of the expansion of nickel reported in the literature were analyzed critically, resulting in a compilation of α of nickel from 0 to 1500 K. Theories of thermal expansion were employed to separate α into its paramagnetic αp and magnetic αm components. The calculated values of αm near TC were fitted to the power-law equation, αm=A(ta1)a1+B, that describes critical phenomena near the critical temperature [t=(TTC)TC1]. It was demonstrated that the critical exponents above and below TC, a and a, respectively, are the same as those derived from specific-heat measurements and that a=a=0.093(±0.010) in agreement with scaling laws of critical phenomena.