I. The Ferromagnetic Alloy System Copper-Manganese-Indium. II. A Volumetric Method for the Determination of Indium

A phase-equilibria study of the copper-rich portion of the copper-magnase-indium system has been made, using thermal, microscopic, and magnetic measurements. The thermal data was obtained from cooling curves in the region of solidification, and melting-point contours are given. Microscopic data on the high- tempera.tu.re solid phases was obtained by annealing the alloys at temperatures just below the solidus, then quenching and observing them under the microscope. The magnetic work consisted of Curie point measurements on the alloys as originally prepared, after quenching, and after reannealing at 100°C. On the basis of these results, approximate locations of the [Formula. See abstract in scanned thesis for details] phase boundaries are given. Ferromagnetism has been found to exist over mo.st of the composition diagram. An attempt has been made to apply a known method for the volumetric determination of zinc to the determination of indium. The procedure consists of adding an excess of potassium iodide and potassium ferricyanide to a buffered solution of indium, and titrating the liberated iodine with sodium thiosulfate. Within very restricted ranges of concentration, results accurate to ±1% were obtained, but the method is not considered usable at present.