Effect of Carbon on the Electrical Resistivity of Ni–Al Intermetallic Alloy Synthesized by an Electrothermal Explosion under Pressure

Abstract

The effect of carbon (3 wt %) on the electrical resistivity of alloys based on aluminum nickelides Ni-Al and Ni-Al-C synthesized by electrothermal explosion in the temperature range of 300-1300 K in a vacuum of 2 × 10 -3 Pa has been studied. At an electrothermal explosion in a powder reaction medium, a Ni-Al-based melt is formed in which carbon dissolves. It is shown that, during the crystallization of the final product, due to its low solubility in Ni-Al, carbon is located at the boundaries of intermetallic grains of Ni-Al in the form of multilayer graphite nanofilms 50-80 nm thick, filling the intergranular space. It is shown that the synthesized alloys have a metallic character of conductivity, and the electrical resistivity in the measured temperature range of 300-1300 K increases monotonically for Ni-Al from 16 to 40 μΩ cm and for the carbon-bearing alloy Ni-Al-C from 22 to 60 μΩ cm. In this case, an increase in the temperature coefficient of resistance (TCR) is also observed from 1.45 × 10 -3 K -1 for Ni-Al to 1.77 × 10 -3 K -1 for Ni-Al-C. The slope of the curves of the dependence of electrical resistance on temperature in the studied temperature range of 300-1300 K remains constant and is well described by a linear function.