Comparison of Nichrome Ni80Cr20, Nickel and Inconel 718
Comparison of Nichrome Ni80Cr20, Nickel and Inconel 718
The results for Ni80Cr20 are compared to the respective results for pure nickel and Inconel 718[13] and Inconel 718 at melting almost coincide with our respective measurements. The added literature values for chromium clearly display, that the melting point of chromium is by far the highest out of this material selection. Enthalpy values of all considered metals are very similar.
As the trends of thermal conductivity and thermal diffusivity are very similar, depicts thermal conductivity only. It is evident, that the traces calculated according to contain the reciprocal of the electrical resistivity. The strong resistivity increase of chromium with increasing temperature leads to a reversal of the trend in thermal conductivity (decreasing with increasing temperature).
The electrical resistivity as a transport property is much more sensitive to changes in composition. Heat capacities can be assumed similar to the respective pure elements, whereas electrical resistivity undergoes drastic changes. In the case of resistivity and thermal conductivity, Ni80Cr20 falls in the gap between pure nickel and Inconel 718. In the case of volume expansion and enthalpy the differences are alternating and too small to be judged.
Investigations of alloys like Ni80Cr20 are currently in the focus of interest as they bridge the gap between pure elements and highly alloyed materials. The results for Ni80Cr20 are presented in this work and are compared to pure nickel and Inconel 718 measured under the same experimental conditions. They reveal that different types of connections are possible: First, the behaviour of the alloy is different from the average of its main constituents (see electrical resistivity). Regarding the possible applications of this alloy as heating elements, a higher electrical resistivity is wanted. Second, electrical resistivity of Ni80Cr20 is between nickel and Inconel 718 (but closer to Inconel 718). Third, the differences in specific enthalpy and volume expansion are small.