The question as it appears in the 01/02 edition of Specs & Techs from GlobalSpec:
Juan and Tomas work in a munitions factory loading explosives into non-sparking, non-ferrous alloy containers. Juan wants to automate the manufacturing process by automatically picking up and moving the containers with an electromagnetic lift system. Vacuum or mechanical pick-and-place systems have failed. The current container alloy is a non-magnetic zinc alloy, but the munitions will function with containers fabricated from other non-sparking copper, aluminum, or zinc alloys. Can Juan and Tomas find or make a non-sparking, non-ferrous and ferromagnetic alloy for container fabrication?
(Update: Jan 8, 8:44 AM EST) And the Answer is...
A manganese-aluminum bronze or copper-manganese-aluminum based Huesler alloy could be used to provide a container material (see http://en.wikipedia.org/wiki/Heusler_alloy ). Heusler alloys are ferromagnetic materials based on non-ferromagnetic metals such as copper, manganesepercentand aluminum. Certain copper-manganese-tin and copper-manganese-aluminum alloys also exhibit ferromagnetism. In 1903, an engineer, Heusler, first observed that a copper-based alloy with 16% Mn, 8% Al and small lead additions exhibited ferromagnetism. The formation of a ferromagnetic intermetallic Heusler phase produces in ferromagnetism. The magnetic domain structure is modified by thermal anti-phase boundaries during cooling. Heusler alloys have recently become important in the emerging field of magnetoelectronics or spintronics
Heusler's Magnetic Alloy of Manganese, Aluminium, and Copper Heusler's Magnetic Alloy of Manganese, Aluminium, and Copper. ANDREW G RAY( Proc. Roy. Soc., 1906, A, 77, 256-259.
Compare Fleming and Hadfield, Abstr., 1905, ii, 799).-A rod containing about 16 percent. of manganese, 8 per cent. of aluminum, a little lead, and the rest copper, was found to be almost nonmagnetic. After heating at 340" for about twenty minutes, its magnetic properties were much more pronounced. The critical temperature being about 350", heating at 400" and immersion in cold water practically destroyed the magnetic quality. When the quenched alloy, however, was tested at the temperature of liquid air, it was found to be more susceptible to magnetism than in its previous best condition, whilst exhibiting 'much less hysteresis and retentiveness.
J. C. P.
http://www.informaworld.com/smpp/content?content=10.1080/00107516908204800
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