Characterization of some iron rich nickel-iron alloys

Characterization investigations were carried out for Ni-Fe alloys for three different concentrations of iron. The starting and ending temperatures of the fcc-bcc phase transformation both on heating and on cooling were obtained by measuring the resistance as a function of temperature; the results agree with previous work. We also measured the lattice constants of both structures by using a modified Debye-Scherrer method. For the fcc structure a is 3.5837 A, for the bcc structure a is 2.875 A, and we noticed a decrease of the lattice constant as the iron concentration is increased. Auger electron spectroscopy was carried out for the purpose of studying the surface segregation and a concentration analysis was attempted. The results show that Ni is preferentially sputtered but an annealing process can overcome this segregation. Magnetic measurements show a change of magnetization with temperature though the data is insufficient to obtain the average moment.