Influence of Addition of Nickel on the Thermal Expansion, Rigidity Modulus and Its Temperature Coefficient of the Alloys of Cobalt, Iron and Chromium, Especially of Co-Elinvar. II : Additions of 30 and 40 per cent of Nickel
The influence of additions of 30 and 40 per cent of nickel on the thermal expansion in the range from 10 to 50°, rigidity modulus at 20°and its temperature coefficient in the range from 20 to 50°of the alloys of cobalt, iron and chromium was studied. The relations between those properties and the concentrations of nickel-added alloys were almost similar qualitatively to those in the case of the ternary alloys of cobalt, iron and chromium, that is, there were two groups of alloys, one showing a positive temperature coefficient of rigidity modulus and the other a negative. And it has been found that the content of cobalt at the composition showing the smallest value of the coefficient of thermal expansion and the largest positive maximum of the temperature coefficient of rigidity modulus decreases with the increase of nickel content and finally reaches zero at the composition of invar in the binary system of nickel and iron, while the content of chromium does not change until that of nickel reaches about 15 per cent, then gradually decreases and becomes zero at the composition of about 30 per cent of nickel and the rest of iron. In the case of addition of 30 per cent of nickel, the smallest thermal expansion coefficient was 1.87×10^<-6>, while in the case of addition of 40 per cent, it was 0.54×10^<-6>. The largest positive values of the temperature coefficient of rigidity modulus in the corresponding cases were respectively +76.4×10^<-5> and +81.0×10^<-5>. The largest and smallest values of rigidity modulus in the case of addition of 30 per cent of nickel were 7.84×10^<5>kg/cm^2 and 4.55×10^<5>kg/cm^2, and in the case of 40 per cent of nickel they were respectively 8.96×10^<5>kg/cm^2 and 4.69×10^<5>kg/cm^2.
- Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy
Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy 7 533-540, 1955