German surplus ammo question

[Delkal]

Could someone explain how CuNi would be magnetic?

What? You don't have all of the back issues to Physical Reviews Journal from the American Physical Society?

Abstract

The magnetic susceptibility of alloys of copper and nickel in proportions ranging from 0.1 to 70 percent nickel have been studied. X-ray photographs of the alloys show that they are a homogeneous mixture of the copper and nickel crystals. Although copper is only weakly diamagnetic it requires 0.8 or 0.9 percent nickel to neutralize this diamagnetic effect and 56 percent nickel is required before the alloy shows ferromagnetic properties at ordinary temperatures. For amounts of nickel from one percent up to 30 percent the alloy, while paramagnetic in most respects, does not obey any known law of paramagnetism with regard to temperature. As the temperature is increased the susceptibility first increases and then decreases, the maximum occurring in the neighborhood of the Curie point for nickel. In the case of alloys containing more than 30 percent nickel the susceptibility decreases with increase of temperature for temperatures above 20°C.

Received 27 June 1931

DOI:https://doi.org/10.1103/PhysRev.38.828

©1931 American Physical Society