The Electrical Resistance of Metals and Alloys in Their Hard and Soft States

It is known that the electrical resistance of annealed metals is usually smaller than that of metals in their cold worked state. The curve showing the relation between electrical resistance and annealing temperature reaches a minimum; continued annealing at higher temperature produces an increase in the electrical resistance. In the case of alloys it has been noted that a second decrease occurs at higher annealing temperature. The following work corroborates the observance of previous investigations. The electrical resistance of cold worked copper, gold, nickel, and iron decreased with annealing and then increased, the minimum being around 300° C. or 400° C. Monel metal showed a minimum resistance followed by an increase which in turn was followed by a second decrease.

The Rate of Precipitation of Copper Aluminide in the Silver Rich Silver-Copper-Aluminum Alloys

In order to determine the best annealing temperature at which to age-harden the alloys, hardness tests on speci­men annealed for different lengths of time at different temperatures were made.

Alloys of Lead and Tellurium

Prior to the last few years little practical use was made of the element tellurium, which is obtained from gold and silver tellurides and from the slimes of electro­lytic copper refineries. Lately, however, more study has been made of its properties when alloyed with other metals. It was the purpose of this thesis to study the effects of the addition of tellurium to lead, particularly in small amounts.

An Investigation of the Properties of some of the White Metal Alloys

Although there is no standardized list of alloys, most investigators have, to avoid confusion, concurred in at least grouping the metals under several general heads. Precious metals: gold, silver and the platinum group; the light metals: aluminum and magnesium; the non-ferrous metals (excluding all steels and iron-base alloys); and the antifriction metals.

The Electrical Conductivity of the Copper-Aluminum Alloys.

Among the many aluminum alloys which have been studied are the binary copper-aluminum alloys. These have proven to be among the most useful of the alumi­num alloys thus far worked upon.

Age Hardening of Silver-Platinum Alloys

The alloy system selected for study was the binary alloy of platinum and silver. An examination of the various silver alloy diagrams revealed that of several possible alloys, the silver platinum was the most suit­able with regard to solubility.

Some Preliminary Investiagtions of the Magnetic Permeabilities of Alloys of the Ferromagnetic Metals

The problem presented for this thesis was an investigation of the magnetic properties of the alloys produced by the methods of powder metallurgy. The question behind this was the correlation of the magnetic properties with the bonding properties and with the diffusion of the constituents.

The Electroformation of Lithium-Lead Alloys from Molten Electrolytes

An attempt was made to make lead-lithium alloys by electrodeposition of lithium using a molten bath and a molten lead cathode.The variables taken into consideration were: composition of the melt, temperature of the melt, and current density. The purpose of changing these factors was to determine what effect each had on the current efficiency.

Some Effects of the Addition of Tellurium to Lead Alloys

From the standpoint of its practical useful­ness, the most important characteristics of metallic lead are its cheapness, resistance to corrosion, plas­ticity, high specific gravity, low melting point, and its ability to form alloys in which some properties are modified by the addition of other elements, while other properties remain the same.

The Electrodeposition of Iron-Manganese Alloys

Various electrolytes were experimented with in an attempt to deposit an iron-manganese alloy. An Alloy was obtained from a solution containing ferrous ammonium sulfate, manganous sulfate, and ammonium sulfate. Further experimentation was done in an effort to determine the optimum conditions of deposition and the highest manganese alloy which could be produced.

The Electrodeposition of Iron-Manganese Alloys

An electrodeposition of an iron-manganese alloy was made from the same conditions determined by previous re­search. Various addition agents were experimented with in an attempt to produce better conditions for electro-deposition. It was found advantageous to add small a­mounts of sodium lauryl sulfate and ammonium sulfite to the electrolyte.

Age Hardening of Copper Antimony Alloys

A large number of alloys of varying percentages of copper and antimony were prepared. These alloys were treated in various ways which might be expected to produce age hardening. The effect of cold working was studied in the range where the alloys were malleable.

The Electrodeposition of Copper-Cobalt Alloys

An attempt was made to deposit a 50:50 copper-cobalt alloy from various sulfate electrolytes. No true 50:50 alloy was obtained but various mixtures of cobalt and copper rich crystals were deposited.

Hydrogen Overvoltage of Cadmium Bismuth and Antimony Bismuth Alloys

A method to measure hydrogen overvoltage was devel­oped and checked with metals of known overvoltage. Alloys of bismuth and antimony and of bismuth and cad­mium were prepared and their overvoltages determined.

Corrosion Testing of Iron-Tin Alloys by the Salt Spray Method

The purpose of this study was to determine the rela­tive rate of corrosion of iron-tin alloys containing low percentages of tin. Since in the world today, a great deal of work is being done to develop large tin deposits and new methods devised to treat these ores, it is possible that the metal will become abundant and will obtain a more important position in the metal industry.